• Youth admitted to the inpatient unit at either site for a recent suicide attempt or significant suicidal ideation with a plan or intent.
• The youth and parent are able to complete assessments in English, and the youth is able to complete therapy.
• The youth currently exhibits psychosis.
• The youth currently exhibits mania.
• The youth is currently <85% of their ideal body weight.
• The youth is intellectually incapable of completing the study, e.g. has an intelligence quotient (IQ) < 70.

• Age 50 and older
• Native English speakers
• 12 years of education or higher
• Active diagnosis of aMCI
• History of TBI based on VA/DOD criteria
• TBI within the past 2 years
• Lifetime history of stroke, transient ischemic attack, heart attack, or congestive heart failure
• Lifetime history of epilepsy
• Major psychiatric disorders (i.e., posttraumatic stress disorder, bipolar disorder, schizophrenia)
• Substance use disorder
• Has metal fragments in head
• Taking medications that may interact with the HD-tDCS effect (i.e., amphetamines, L-dopa, carbamazepine, sulpiride, pergolide, lorazepam, dextromethorphan, D-cycloserine, flunarizine, or ropinirole)

Inclusion Criteria Study participants must: 1. Be adolescents (aged 13-18 years); 2. Have had a recent suicidal event (suicide attempt or significant suicidal ideation with a plan or intent warranting emergency evaluation or inpatient hospitalization within the past 30 days); 3. Receiving standard of care treatment that includes clinically indicated psychosocial and/or psychopharmacological treatment; 4. Have a current primary diagnosis of a depressive disorder based on the MINI-KID (other psychiatric disorders are acceptable, but must not be primary); 5. Both participants and their designated caregiver must be able to complete assessments in English, as the rating scales vital to study efficacy and safety evaluations have not been validated in Spanish. (NOTE: Most potential participants ages 13 to 18 years old, as well as most of their parents, have a good working knowledge of English); 6. Use effective method of contraception during and for 90 days following the end of treatment for female and male participants. Recommended methods of birth control are namely, consistent use of an approved hormonal birth control (pill/patches, rings), an intrauterine device (IUD), contraceptive injection, double barrier methods, sexual abstinence, or sterilization; Exclusion Criteria Study participants must not: 1. Have lifetime schizophrenia, psychotic disorder, pervasive developmental disorder, or mental retardation; 2. Have current mania, hypomania, mixed episode, or obsessive-compulsive disorder; 3. Have a primary diagnosis other than a depressive disorder; 4. Have moderate to severe alcohol or substance use disorder within the past six months (based on MINI-KID); If there is a positive urine drug screen at screening, the urine drug screen will be repeated at each infusion visit. Positive urine drug screen will be reviewed by study physician and infusion will proceed as long as no safety risk was identified; 5. If female, be pregnant, lactating, or nursing; Women of childbearing potential must have a negative urine pregnancy test prior to all infusions; 6. Have unstable medical conditions (stable for less than 3 months) or with clinically significant laboratory values or an electrocardiogram (ECG) that would pose significant risk; 7. Be at serious suicidal risk that cannot be managed in the outpatient setting; 8. Have prior treatment for depression with or contraindications to ketamine, esketamine, or, midazolam; 9. Treatment with medications that may alter pharmacokinetics of ketamine, including moderate-to-strong inhibitors or inducers of CYP3A4 and CYP2B6, is exclusionary. Regarding pharmacodynamic interactions, medications that may increase heart rate or blood pressure such as the ADHD stimulant medications will be permitted with last dose at least 24 hours prior to infusion. All concomitant medications will be evaluated by the study physician to determine if the type and dose of concomitant medication requires discontinuation and will be excluded if the concomitant medication could substantially increase the risk of study infusion. A complete list of medications that are Not Allowed is available in Appendix D of the protocol. The study team will not ask the participant to discontinue any treatment (except for not taking ADHD medications for 24 hours before study treatment) just for the sake of taking part in this study; 10. Weigh >120 kilograms at baseline. If participants are enrolled but exceed 120 kilograms at any time during the treatment period, they will be removed from the treatment portion of the study.

• Younger than 2 years (chronological age)
• Scheduled for anaesthesia that is expected to last at least 2 hours (and/or total operating room time is scheduled to be at least 2.5 hours)
• Has a legally acceptable representative capable of understanding the informed consent document and providing consent on the participant's behalf.
• Known neurologic, chromosomal or congenital anomaly which is likely to be associated with poor neurobehavioural outcome
• Existing diagnosis of behavioural or neurodevelopmental disability
• Prematurity (defined as < 36 weeks gestational age at birth)
• Birth weight less than 2 kg.
• Congenital cardiac disease requiring surgery
• Intracranial neurosurgery and intracranial craniofacial surgery (isolated cleft lip is not an exclusion)
• Previous cumulative exposure to general anaesthesia exceeding 2 hours
• Planned future cumulative exposure to anaesthesia exceeding 2 hours before the age of 3 years.
• Any specific contra-indication to any aspect of the protocol
• Previous adverse reaction to any anaesthetic
• Circumstances likely to make long term follow-up impossible
• Living in a household where the primary language spoken at home is not a language in which we can administer the Wechsler Preschool and Primary School Intelligence Scale
• Planned postoperative sedation with any agent except opioids (e.g. benzodiazepines, dexmedetomidine, ketamine, barbiturates, propofol, clonidine, chloral hydrate, and other non-opioid sedatives). For example if such sedation is planned for post-operative ventilation

• Outpatient men and women age 18-65 years old with bipolar I, II, Not Otherwise Specified (NOS) disorder, or Schizoaffective Bipolar Type
• If diagnosed with Bipolar I, Bipolar NOS w/history of mania or Schizoaffective Disorder Bipolar Type, current mood stabilizer therapy (lithium, valproic acid, lamotrigine, gabapentin) with stable dose for > 28 days prior to randomization.
• Baseline Barrett Impulsiveness Scale-11 Score of > 62 (above average impulsivity)
• Systolic BP > 100 and < 165 and Diastolic BP > 60 and < 105 with no evidence of orthostatic hypotension
• Current Diagnosis of Alcohol Use Disorder with at least moderate severity
• Alcohol use of an average of 15 drinks per 7 days in the past 28 days prior to intake for men, and an average of 8 drinks per 7 day period in the past 28 days prior to intake for women
• Current mood stabilizer therapy with stable dose for > 28 days
• Fluent in English or Spanish
• Baseline Hamilton Rating Scale for Depression (HRSD) or Young Mania Rating Scale (YMRS) scores > 35
• Mood disorders other than bipolar I, II, NOS or schizoaffective disorder bipolar type (e.g. cyclothymic disorders, schizophrenia, schizoaffective disorder depressive type, or unipolar depression based on the SCID), other disorders, e.g. anxiety disorders, will be allowed.
• Current diagnosis of amphetamine or cocaine use disorder or a cocaine or amphetamine positive baseline urine sample.
• Evidence of clinically significant alcohol withdrawal symptoms
• Current treatment with an atypical antipsychotic
• Current treatment with naltrexone, acamprosate, disulfiram, or topiramate in the last 28 days
• Prior treatment with Aripiprazole within the last year or lifetime history of intolerable side effects to Aripiprazole
• Vulnerable populations (e.g. pregnant, nursing, cognitively impaired, incarcerated.)
• Evidence of clinically significant alcohol withdrawal symptoms defined as a CIWA-Ar score of ≥ 10.
• High risk for suicide
• Aspartate Amino Transferase (AST) or Alanine Amino Transferase (ALT) > 3 times upper limit of normal
• Current use of Cytochrome P450 3A4 inducing medication (e.g. carbamazepine, rifabutin, rifampin, ritonavir).
• Use of other substances (besides cocaine/amphetamine) is allowed if the use disorder is no greater than moderate severity and alcohol is the self-identified substance of choice.
• History of neuroleptic malignant syndrome or tardive dyskinesia. More specific inclusion and exclusion criteria will be discussed with participant at baseline assessment.

• Participant must meet the Diagnostic and Statistical Manual of Mental Disorders (5th edition) (DSM-5) diagnostic criteria for single-episode MDD or recurrent MDD, without psychotic features, based upon clinical assessment and confirmed by the MINI. Participants 65 years of age or older must have had the first onset of depression prior to 55 years of age
• Participant must have had nonresponse (<=25% improvement) to >=2 oral antidepressant treatments in the current episode of depression, assessed using the MGH-ATRQ, and confirmed by documented records (example, medical/pharmacy/prescription records or a letter from a treating physician)
• Participant must have an Inventory of Depressive Symptomatology-Clinician rated, 30-item (IDS-C30) total score of >=34
• The participant's current major depressive episode, depression symptom severity, and antidepressant treatment response in the current depressive episode, must be confirmed by the State vs. Trait, Assessibility, Face Validity, Ecological Validity, Rule of Three P's (SAFER) Interview
• Participant must be medically stable on the basis of physical examination, medical history, vital signs (including blood pressure), and 12-lead electrocardiogram (ECG) performed in the screening phase. If there are any abnormalities that are not specified in the inclusion and exclusion criteria, the determination of their clinical significance must be determined by the investigator and recorded in the participant's source documents and initiated by the investigator
• Participant must be medically stable on the basis of clinical laboratory tests performed in the screening phase. If the results of the serum chemistry panel, hematology, or urinalysis are outside the normal reference ranges, the participant may be included only if the investigator judges the abnormalities or deviations from normal to be not clinically significant or to be appropriate and reasonable for the population under study. This determination must be recorded in the participant's source documents and initialed by the investigator: (a) Participants with a pre-existing history of thyroid disease/disorder who are treated with thyroid hormones must be on a stable dosage for 3 months prior to the start of the screening phase; (b) For any participant (regardless of thyroid history), if the thyroid-stimulating hormone (TSH) value is out of range, a free thyroxine (FT4) will be conducted. If the FT4 value is abnormal and considered to be clinically significant (after discussion with the medical monitor), the participant is not eligible
• Participant must be comfortable with self-administration of nasal spray medication and be able to follow the nasal spray administration instructions provided
• The participant has used ketamine/esketamine (lifetime)
• The participant's depressive symptoms have previously demonstrated nonresponse to an adequate course of treatment with electroconvulsive therapy (ECT) in the current major depressive episode, defined as at least 7 treatments with unilateral/bilateral ECT
• Participant has received vagal nerve stimulation (VNS) or has received deep brain stimulation (DBS) in the current episode of depression
• Participant has a current or history of seizures (uncomplicated childhood febrile seizures with no sequelae are not exclusionary)
• Participant has any anatomical or medical condition that, per the investigator's clinical judgment based on assessment, may impede delivery or absorption of nasal spray study drug

Subjects must meet all of these criteria for inclusion in the study: 1. The subject has completed written informed consent. 2. At the time of signing the informed consent, subject must be 18 to 65 years of age, inclusive. 3. The subject has a primary diagnosis of Major Depressive Disorder (MDD), without psychotic features, meeting the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) criteria. 4. Subject must have had inadequate response to antidepressant treatment. 5. Subject is currently on stable pharmacological treatment for depression. 6. Subject must have a total Hamilton Depression Rating Scale-17 Item (HAMD17) score ≥ 22 at screening. 7. Subjects must have been taking current antidepressant medication(s) for ≥ 8 weeks. 8. Subjects must be willing to comply with all study procedures and restrictions. Subjects will be excluded from the study if they meet any of the following criteria: 1. Subject is pregnant or breastfeeding. 2. Subject has an unstable medical condition or chronic disease. 3. Subject has a history of neurological abnormalities. 4. Subject is currently diagnosed with or prior diagnoses of psychiatric disorder which was the primary focus of treatment other than MDD. 5. The subject's depressive symptoms have previously demonstrated nonresponse to an adequate course of treatment with electroconvulsive therapy (ECT). 6. The subject has an alcohol or substance use disorder. 7. In the Investigator's opinion, the subject is not capable of adhering to the protocol requirements.

1. Male or females age 14-18 inclusive 2. Diagnosed with concussion due to sports-related injury. Concussion is defined as: 1. Direct blow to the head, face, neck or a blow elsewhere on the body with an "impulsive" force transmitted to the head. 2. Rapid onset of short-lived impairment of neurologic function in one or more of the following clinical domains that resolves spontaneously: i. Symptoms: somatic (eg, headache), cognitive (eg, feeling like in a fog and/or emotional symptoms (eg, lability). ii. Physical signs (eg, loss of consciousness, amnesia). iii. Behavioral changes (eg, irritability). iv. Cognitive impairment (eg, slowed reaction times). v. Sleep disturbance (eg, drowsiness). c) No abnormality on standard structural neuroimaging studies, if such neuroimaging studies are completed for a clinically-indicated reason. Note: neuroimaging is not a part of this study protocol. Study participants will not undergo neuroimaging as part of this study. 3. Concussion within 4 days of enrollment 4. Presenting for treatment to the Sports Medicine Center at Children's Medical Center 1. Subjects not actively participating in an organized sport at time of enrollment 2. Subjects who received a concussion from an event other than playing a sport (motor vehicle accident, fall, etc.) 3. Subjects who participate in or received a concussion during participation in motorized sports (i.e., motorcross, dirt biking, jet skiing, etc.) 4. Subjects with radiographic evidence of traumatic brain injury (i.e., skull fracture, intracranial hemorrhage, cerebral contusion, etc). 5. Subjects with a prior diagnosed concussion in the previous 6 months. 6. Pregnant women. 7. Subjects sensitive to aspirin 8. Subjects diagnosed with high blood pressure and currently being treated with blood pressure medications 9. Subjects allergic to soy bean oil or corn oil. 10. Subjects currently taking fish oil or DHA supplements.

Inclusion Criteria Patients will be included if they: 1. are inpatients or outpatients; 2. are voluntary and competent to consent to treatment and research procedures according to ECT/MST attending psychiatrist; 3. have a MINI International Neuropsychiatric Interview diagnosis, Version 6 (MINI-6.0) diagnosis of non-psychotic MDD 4. are 18 years of age or older 5. have a baseline HRSD-24 score > or = 21; 6. are considered to be appropriate to receive convulsive therapy as assessed by an ECT attending psychiatrist and a consultant anaesthesiologist 7. are agreeable to keeping their current antidepressant treatment constant during the intervention; 8. are likely able to adhere to the intervention schedule; 9. meet the MST safety criteria [75]; 10. If a woman of child-bearing potential: is willing to provide a negative pregnancy test and agrees not to become pregnant during trial participation. Exclusion Criteria Patients will be excluded if they: 1. have a history of MINI diagnosis of substance dependence or abuse within the past three months; 2. have a concomitant major unstable medical illness; 3. are pregnant or intend to get pregnant during the study; 4. have a MINI diagnosis of any primary psychotic disorder 5. have a MINI diagnosis of obsessive compulsive disorder, or post-traumatic stress disorder deemed to be primary and causing more functional impairment than the depressive disorder 6. have probable dementia based on study investigator assessment; 7. have any significant neurological disorder or condition likely to be associated with increased intracranial pressure or a space occupying brain lesion, e.g., cerebral aneurysm; 8. present with a medical condition, a medication, or a laboratory abnormality that could cause a major depressive episode or significant cognitive impairment in the opinion of the investigator (e.g., hypothyroidism with low TSH, rheumatoid arthritis requiring high dose prednisone, or Cushing's disease); 9. have an intracranial implant (e.g., aneurysm clips, shunts, stimulators, cochlear implants, or electrodes) or any other metal object within or near the head, excluding the mouth, that cannot be safely removed; 10. require a benzodiazepine with a dose > lorazepam 2 mg/day or equivalent or any anticonvulsant due to the potential of these medications to limit the efficacy of both MST and ECT; 11. are unable to communicate in English fluently enough to complete the neuropsychological tests; 12. have a non-correctable clinically significant sensory impairment (i.e., cannot hear or see well enough to complete the neuropsychological tests).

•Male or female, age greater than or equal to 45 years at the time of signing informed consent
•Body mass index (BMI) greater than or equal to 27 kg/m^2
•Have established cardiovascular (CV) disease as evidenced by at least one of the following: prior myocardial infarction; prior stroke (ischemic or haemorrhagic stroke); or symptomatic peripheral arterial disease (PAD), as evidenced by intermittent claudication with ankle-brachial index (ABI) less than 0.85 (at rest), or peripheral arterial revascularization procedure, or amputation due to atherosclerotic disease Exclusion Criteria:
•Any of the following: myocardial infarction, stroke, hospitalisation for unstable angina pectoris or transient ischaemic attack within the past 60 days prior to the day of screening
•HbA1c greater than or equal to 48 mmol/mol (6.5 %) as measured by the central laboratory at screening
•History of type 1 or type 2 diabetes (history of gestational diabetes is allowed)

• Men and women (non-pregnant) between ages 21 and 70;
• DSM-5 diagnosis a current major depressive episode (MDE) for 10 years of less, recurrent or single episode with first episode after adulthood and did not start during childhood or adolescence, secondary to nonpsychotic unipolar major depressive disorder;
• Current index MDE ≥24 months duration and/or recurrent illness with at least a total of 2 lifetime episodes (including current episode >12 months);
• Treatment resistance (defined by criteria on the Antidepressant Treatment History Form (ATHF)28): Failure to respond to a minimum of four adequate depression treatments from different categories;
• Symptom severity for Screening: Hamilton Depression Rating Scale-17 item (HDRS17) ≥20;
• Symptom severity for Outcome: Montgomery Asberg Rating Scale (MADRS) ≥27 to be met at assessment one week pre-op;
• Normal brain MRI within 3 months of surgery;
• Antidepressant medication regimen has been held stable for ≥ 30 days prior to the study screening MADRS;
• Remain on stable antidepressant medication throughout the study, unless there are safety concerns;
• Montreal Cognitive Assessment (MoCA) >25;
• Able and willing to give informed consent and agree to attend regular clinic visits for at least 12 months.
• DSM-5 Axis I Disorders: any lifetime history of psychotic disorder or bipolar disorder;
• Alcohol or substance use disorder within 6 months, excluding nicotine;
• History of childhood abuse (physical or sexual) 18
• Personality disorders;
• Seeking disability during the trial;
• Current substantial suicidal risk as defined by a plan or clear immediate intent for self-harm, or made any suicide attempt within the last year; (MADRS ≥ 5 including the day of surgery);
• No stable work history;
• Neurological/Medical condition that makes the patient, in the opinion of the surgeon, a poor candidate; 1. Pregnant or has plans to become pregnant in the next 36 months; 2. Unable/unable to practice birth control through the period of randomization and withdrawal of therapy;
• Subjects who have a history of a seizure disorder;
• Subjects who will be exposed to diathermy;
• Subjects who have any medical contraindications to undergoing DBS surgery (e.g. infection, coagulopathy, or significant cardiac or other medical risk factors for surgery);
• Subjects with another implanted device such as a cardiac pacemaker, defibrillator or neurostimulator;
• Subjects who have a history of hemorrhagic stroke;
• Subjects who are unable to undergo MRI;
• Subjects who are at increased risk of hemorrhage due to underlying medical conditions or medication.

• Women and men of reproductive potential should agree to use an appropriate method of birth control throughout their participation in this study due to the teratogenic potential of the therapy utilized in this trial. Appropriate methods of birth control include abstinence, oral contraceptives, implantable hormonal contraceptives or double barrier method (diaphragm plus condom)
• Diagnosis of advanced cancer
• Patient-reported 2-month weight loss of at least 5 pounds (2.3 kilograms) and/or physician-estimated caloric intake of less than 20 calories/kilogram of body weight per day
• The patient must perceive loss of appetite and/or weight as a problem; and have an appetite score of 4 or worse on the "Please rate your appetite…." question that requires a patient response on a 0-10 numeric rating scale
• Not receiving ongoing tube feedings or parenteral nutrition at the time of registration
• Not currently using systemic adrenal steroids (with the exception of short-term dexamethasone within 3 days of chemotherapy for control of chemotherapy side effects)
• No use of androgens, progesterone analogs, or other appetite stimulants within the past month
• Patient should not have poorly controlled hypertension or congestive heart failure at registration
• Patient should not have an obstruction of the alimentary canal, malabsorption, or intractable vomiting (defined as vomiting more than 3 times per day over the preceding week)
• Not currently using olanzapine for another medical condition or had previously used olanzapine for chronic nausea or for any pre-existing psychotic disorder
• Patient should not have had a previous blood clot at any time in the past
• No history of poorly controlled diabetes
• No symptomatic leptomeningeal disease or known brain metastases as these patients may have difficulty taking oral medications
• No history of hypersensitivity to olanzapine or megestrol acetate
• No COVID-19 infection in the past that, in the opinion of the treating physician, had left patients with compromised taste, which has not resolved at the time of registration
• Not pregnant and not nursing, because this study involves an investigational agent whose genotoxic, mutagenic and teratogenic effects on the developing fetus and newborn are unknown. Therefore, for women of childbearing potential only, a negative urine or serum pregnancy test done =< 14 days prior to registration is required
• Age >= 18 years
• Eastern Cooperative Oncology Group (ECOG) performance status 0, 1 or 2
• Estimated life expectancy of 3 months or longer
• Serum creatinine =< 2.0 mg/dL
• Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) =< 3 x upper limit of normal (ULN)
• Fasting glucose > 1410 mg/dl
• Granulocytes > 1000/hpf
• No treatment with another antipsychotic agent, such as risperidone, quetiapine, clozapine, butyrophenone within 30 days of enrollment
• In order to complete the mandatory patient-completed measures, participants must be able to speak and/or read English or Spanish. Sites seeking to enroll Spanish-speaking patients should have access to Spanish speaking staff on site or through the use of a translation service to be able to conduct the informed consent discussion in Spanish, and to conduct the weekly phone calls
• Psychiatric illness which would prevent the patient from giving informed consent
• Medical condition such as uncontrolled infection (including human immunodeficiency virus [HIV]), uncontrolled diabetes mellitus or cardiac disease which, in the opinion of the treating physician, would make this protocol unreasonably hazardous for the patient
• Patients who cannot swallow oral formulations of the agents
• Patients with impaired decision-making capacity (such as with a diagnosis of dementia or memory loss) are not eligible for this study
• No presence of a hormone-sensitive tumor, such as breast, endometrial, or prostate cancer (this exclusion criterion is intended to circumvent any confounding antineoplastic effects of megestrol acetate)

• Adolescents ages 13 through 18 years, and
• Adolescents must be experiencing an elevated level of depressive symptoms (PHQ-9 = 5-18), and
• Adolescents will be included if they have had past depressive episode/s, but not if they are in a current depressive episode. 1. Outside age range: 1. 12 or younger 2. 19 or older 2. Adolescent is a non-English speaker/reader 3. On the PHQ-9 screening, depression symptom level is: 1. PHQ-9 = 4 or lower 2. PHQ-9 =19 or higher 4. As assessed by the MINI Kid, a current depressive episode 5. As assessed by the MINI Kid, adolescent meets DSM-5 criteria for a psychotic or bipolar disorder. 6. Currently using medication therapy for depression, anxiety, or other internalizing disorders. 7. Currently engaged in individual treatment for a mood disorder (assessed by BCC during phone screen) 8. Currently engaged in a cognitive-behavioral group or therapy (assessed by BCC during phone screen) 9. Any past psychiatric hospitalizations 10. Any past suicide attempt or incident of self-harm with moderate or greater lethality 11. Extreme, current drug/alcohol abuse (determined by clinician follow up following a score of 3 or greater on the CRAFFT) 12. Current suicidal thoughts 1. Eligibility will be determined on a case-by-case basis during the baseline PhQ-9 and MINI Kid assessment process and after a consultation with a licensed mental health clinician has taken place. If adolescent report suicidal ideation on the baseline PhQ-9, and found ineligible, the MINI Kid assessment may not be required. 2. Adolescents with current (within the past 6 months), active suicidal feelings will be excluded. 3. Adolescents with passive thoughts of death or suicide but report to the mental health clinician that they would never act on these thoughts may be admitted, depending on the severity of the risk. 4. Adolescents with past (greater than 6 months ago) ideation who are determined to be low risk will be admitted into the study if there has never been an attempt of moderate or greater lethality. 13. Significant reading impairment (a minimum sixth-grade reading level based on parental report) and/or significant intellectual or developmental disabilities 14. Not willing to comply with the study protocol 15. Did not complete phone assessment with MINI Kid by BCC 16. Not affiliated with any of the sites listed in Appendix A. 17. Parent/guardian does not speak English or Spanish 18. Parent/guardian has a cognitive or intellectual impairment 19. Participant Declined/Changed Mind/Uninterested in participating

1. Male or female subjects, 18-65 years of age and body weight less than or equal to 120 kg on baseline visit. 2. Participants must have a level of understanding of the English language sufficient to agree to all tests and examinations required by the study and must be able to participate fully in the informed consent process. 3. For Healthy Controls: Subjects must be free of any lifetime psychiatric condition based on the Mini-International Neuropsychiatric Interview (MINI). For MDD: Subjects must meet Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for current unipolar depression [major depressive disorder (MDD) or persistent depressive disorder (PDD) in a current major depressive episode (MDE)] based on MINI. 4. A woman of childbearing potential who is sexually active with a male must agree to use an acceptable method of contraception [defined as either one highly effective (permanent sterilization, intrauterine device or hormonal implant) or two other forms of contraception (such as oral contraceptive pill and condom)] to avoid pregnancy throughout the study. Throughout the study and for 90 days (one spermatogenesis cycle) after receiving the last dose of study drug (ketamine/midazolam) man who is sexually active with a woman of childbearing potential must use an acceptable method of contraception (described above) with his female partner and must agree not to donate sperm. 5. Subjects must either be free of psychotropic medications (including antidepressants, antipsychotics, benzodiazepines, mood stabilizers, sedative/hypnotics, dopamine agonists, stimulants, buspirone, and triptans) and certain anticonvulsants (topiramate and levetiracetam) or be stable on these medications for four weeks prior to the baseline visit [first magnetic resonance imaging (MRI) scan]. 6. Subjects with MDD should be willing to participate in neuroimaging scans before and after infusions, and be willing to undergo infusions with study drug. 1. Lifetime diagnosis of schizophrenia or any psychotic disorder, bipolar disorder, pervasive developmental disorder or intellectual development disorder. 2. Current diagnosis of obsessive-compulsive disorder, anorexia nervosa or bulimia. Comorbid anxiety, stress and trauma-related disorders are permitted as long as unipolar depression is the primary diagnosis. 3. Diagnosis of a moderate or severe substance use disorder within the past 6 months per MINI; all subjects must have a negative urine toxicology test on the day of the MRI, prior to the scan. 4. Female subjects who are pregnant, nursing, for may become pregnant. Women of childbearing potential must have a negative urine pregnancy test on the day of the fMRI, prior to scan, and on days of study drug infusion, prior to infusion. 5. Any unstable medical illnesses including hepatic, renal, gastroenterologic, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, immunologic, or hematologic disease. 6. Inadequately treated obstructive sleep apnea (STOP-Bang score of 5-8 if untreated, if using positive airway pressure device then past-month apnea hypopnea index ≥ 15 per hour representing moderate or higher severity). 7. Presence of a significant neurological disease such as Parkinson's disease, primary or secondary seizure disorders, intracranial tumors, or severe head trauma. 8. Presence of neurocognitive or dementing disorders. 9. Clinically significant abnormalities of laboratories, physical examination (including unstable hypertension
•systolic blood pressure >170, diastolic blood pressure >100), or electrocardiogram at screening visit. 10. Subjects judged to be at serious and imminent suicidal or homicidal risk by the PI or another study-affiliated psychiatrist. 11. Any contraindications to MRI, including pacemakers or metallic objects in the body. 12. Any claustrophobia or other conditions which may result in inability to lie still in the MRI scanner for 1 hour or more. 13. Allergy to ketamine or midazolam in subjects with MDD. 14. Must not be on any prohibited concomitant medication.

• Male or female, age above or equal to 18 years at the time of signing informed consent.
• Body mass index (BMI) greater than or equal to 30.0 kg/m^2
• New York Heart Association (NYHA) Class II-IV
• Left ventricular ejection fraction (LVEF) greater than or equal to 45 percentage at screening
• A self-reported change in body weight greater than 5 kg (11 lbs) within 90 days before screening irrespective of medical records
• Haemoglobin A1c (HbA1c) greater than or equal to 6.5 percentage (48 mmol/mol) based on latest available value from medical records, no older than 3 months or if unavailable a local measurement at screening

• Male or female
• Age above or equal to 18 years at the time of signing informed consent
• Body mass index (BMI) greater than or equal to 30.0 kilograms per square meter (kg/m^2) or b) BMI greater than or equal to 27.0 kg/m^2 with the presence of at least one weight-related comorbidity including, but not limited to hypertension, dyslipidaemia, obstructive sleep apnoea or cardiovascular disease
•Glycaemia related: a) Glycated Haemoglobin (HbA1c) greater than or equal to 6.5 percent (48 millimoles per mole [mmol/mol]) as measured by the central laboratory at screening b) History of type 1 or type 2 diabetes mellitus

• Outpatient men and women age 18-70 years old with bipolar I or II disorder or schizoaffective disorder (bipolar type)
• English or Spanish speaking
• Current diagnosis of alcohol use disorder with at least moderate severity (DSM-5 terminology)
• Alcohol use of at least an average of 28 drinks a week if male or an average of 21 drinks per week if female and an average of 3 drinking days a week in the 28 days prior to intake
• Current mood stabilizer therapy (defined as lithium, lamotrigine, carbamazepine, oxcarbazepine or an atypical antipsychotic) with stable dose for ≥ 28 days prior to randomization or valproate/divalproex at a stable dose for ≥ 90 days (longer period due to data suggesting valproate may decrease alcohol use in BPD)
• Diagnosis of substance use disorder other than alcohol, caffeine or nicotine is allowed if 1) alcohol is the self-identified substance of choice and 2) severity of other substance use disorder is ≤ moderate
• Mood disorders other than bipolar I or II disorders or schizoaffective disorder bipolar type (e.g. bipolar NOS, cyclothymic disorders, schizophrenia, schizoaffective disorder depressive type, or unipolar depression based on the SCID); other disorders (e.g. anxiety, will be allowed)
• Baseline HRSD17 or YMRS scores ≥ 35 to exclude those with very severe mood symptoms at baseline
• Evidence of clinically significant alcohol withdrawal symptoms defined as a CIWA-Ar score of ≥ 10
• Current (last 28 days) treatment with naltrexone, acamprosate, disulfiram, or topiramate as these may also decrease alcohol use
• Oral contraceptives and hormone replacement therapy. This exclusion is due to a possible interaction with pregnenolone.
• Women with hormone sensitive conditions such as breast cancer, uterine cancer, ovarian cancer, endometriosis, uterine fibroids. These persons are excluded because pregnenolone is converted to estrogens.
• Vulnerable populations (e.g. pregnant, nursing, cognitively impaired, incarcerated)
• High risk for suicide defined as > 1 attempt in past 12 months that required medical attention, any attempt in the past 3 months or current suicidal ideation with plan and intent such that outpatient care is precluded
• Intensive outpatient treatment (defined as ≥3 visits each week) for substance abuse (AA, NA meetings, or less intensive counseling at baseline will be allowed)
• Severe/unstable condition (e.g. cirrhosis, poorly controlled hypertension) or laboratory/physical exam findings consistent with serious illness (e.g. abnormal electrolytes) or AST or ALT >3 times normal

The participants must meet the following criteria:
• Women aged 40-62 years who are perimenopausal or early postmenopausal (within 5 years of the last menstrual period if not surgically postmenopausal), including:
• Women who have experienced changes in menstrual cycle frequency or duration, and/or physical symptoms indicative of menopausal transition, as determined by clinician
• Women who are using hormonal IUDs (i.e. brands Mirena and Skyla), with FSH level > 20 mIU/m (as menstrual periods are irregular with IUDs that utilize hormones, making irregular/absent periods difficult to assess as related to the menopausal transition).
• Women with significant menopause-related physical symptoms, indicated by any of the following criteria:
• Greene Climacteric Scale total scores > 20
• Greene Climacteric Scale sub-score for vasomotor symptoms >3
• 5 or more bothersome hot flashes per week (self-reported)
• Women meeting DSM-5 criteria for current major depressive disorder (assessed by the SCID)
• Baseline HRSD score of ≥ 18
• Subject agrees to abstain from disallowed medications for the duration of the trial The participants must not meet any of the following criteria:
• Vulnerable populations (e.g. pregnant/nursing, severe cognitive or intellectual impairment, incarcerated)
• Pregnancy (determined by urine pregnancy test), intending pregnancy or breast feeding
• Psychiatric disorder other than MDD that is acute and the primary focus of symptom burden or treatment.
• History of bipolar disorder or psychotic disorder
• Current substance use disorder
• Positive baseline urine drug screen of an illicit substance (in this study: opioids and cocaine,) with the exception of a medication used with a prescription (use of a detected substance that is used with a prescription, such as an opioid pain medication, is not necessarily exclusionary and will be based upon judgment of the PI, particularly in the cases of chronic opioid use). Participants who screen positive for marijuana will be offered a rescreen for eligibility at a later date.
• Current eating disorder
• Treatment resistant depression (failure of 2 adequate antidepressant trials or electroconvulsive therapy (ECT) during current episode; adequate antidepressant trials are defined as within the US FDA approved dosage for the medication and used for at least 6 weeks, with failure described by the patient as <50% improvement based on her subjective experience).
• High risk for suicidal acts including active suicidal ideation with plan and intent or > 2 suicide attempts in lifetime or any attempt in the past 6 months
• Use of selective estrogen-receptor modulators (SERMs), hormone replacement therapy, hormonal contraceptives (hormonal IUDs allowed), episodic sleep medications (chronic, regular, stable-dose benzodiazepines and hypnotics such as zolpidem, Sonata (Zaleplon), and Lunesta (Eszopiclone) OR sleep-seating antihistamines such as Unisom (Doxylamine succinate) or diphenhydramine allowed) within 2 weeks of the baseline visit and randomization. Antidepressants will be allowed for those participants who have been taking the antidepressant for 6 weeks with a stable dose for at least 4 weeks.
• Use of natural menopause and depression supplements, phytoestrogens, soy-based medications, steroids within 2 weeks of baseline visit and randomization.
• Use of any disallowed medications (specified in the Excluded Concomitant Medication section below).
• Women who have received a gonadal hormonal intervention within 1 month prior to study entry (stable thyroid medications are allowed).
• Not using a medically approved method of birth control, if sexually active and not 12 or more months since last menstrual period IUDs, condoms, abstinence are acceptable forms of contraception in this study; due to the possible interactions with the study medication, oral contraceptive pills will be prohibited.
• Uncontrolled hypertension (>160/95mmHg)
• Active coronary artery disease, atrial fibrillation, stroke, deep vein thrombosis, pulmonary embolism or blood clotting disorder
• Any severe, life threatening or unstable medical condition that, based on clinician-judgment, would make participation in the study unsafe or inappropriate
• Personal or first degree family history of known hormone sensitive tumors
• History of allergic reaction or side effects with prior pregnenolone use
• Clinically significant laboratory or physical examination findings
• Concurrent enrollment in another clinical trial Exclusion of Concomitant Medications:
• Selective estrogen-receptor modulators (SERMs)
• Hormone replacement therapy
• Hormonal contraceptives, excluding Mirena IUD or other IUD with localized progesterone
• Natural menopause or antidepressant supplements
• Episodic sleep medications (chronic, regular, stable-dose benzodiazepines and hypnotics such as zolpidem, Sonata (Zaleplon), and Lunesta (Eszopiclone) OR sleep-sedating antihistamines such as Unisom (Doxylamine succinate) or diphenhydramine allowed)
• Sub-therapeutic dosages of antidepressants used for other indications will be permissible with the exclusion of SSRIs, SNRIs, and Wellbutrin.
• Phytoestrogens
• Soy-based medications or supplements

• Men and women age 18-40 years with vision corrected to at least 20-40 (needed for fMRI tasks)
• Education of ≥ 12 years
• Baseline RAVLT total words recalled T-score ≥ 40 (normal range)
• BMI between 18.5-35.0 (neither underweight nor severely obese)
• Baseline QIDS-C ≤ 5 (virtual absence of depressive symptoms) for "healthy controls" and for the "depressed" group a QIDS-C between 11-20 (≥ moderate depressive symptoms but < very severe depressive symptoms)
• History of major psychiatric illness other than MDD for the depressed group, defined as bipolar disorder, posttraumatic stress disorder, schizoaffective disorder, schizophrenia, eating disorders, or MDD with psychotic features. For the control group, a past episode of MDD (per SCID) is also exclusionary
• History of drug or alcohol use disorder
• History of neurological disorders including seizures, brain surgery, multiple sclerosis, Parkinson's disease
• Taking CNS-acting medications (e.g., antidepressants, antipsychotics, lithium, anticonvulsants, sedative/hypnotic/anxiolytics). Thus, the depressed group will be medication free.
• History of allergic reaction or medical contraindication to hydrocortisone
• Metal implants, claustrophobia, or other contraindications to MRI
• Significant medical conditions (e.g., cancer, heart disease, diabetes)
• Vulnerable population including pregnant or nursing women, prisoners, and people with intellectual disability, history of special education classes, dementia, or other severe cognitive disorders
• Current suicidal ideation, a suicide attempt in the past 12 months or more than one lifetime attempt
• History of systemic CS use in the past 12 months, lifetime cumulative use of more than 12 weeks, or recent (defined as past 28 days) inhaled CS use
• Women who are using estrogen containing oral contraceptive agents (other contraceptives are acceptable, see Protection of Human Subjects section for a list of acceptable birth control methods) or who are post- or peri-menopausal or with irregular menstrual cycles (i.e., inconsistent menstruation patterns)

1. Male or female adults aged 18 years or greater. There will be no upper age limit. 2. Presence of CKD stages 3b, 4 or non-dialysis stage 5, with an estimated glomerular filtration rate (GFR) of <45 mL/min/1.73 m2 for a period of at least 3 months, as defined by the National Kidney Foundation and determined using the four-variable Modification of Diet for Renal Diseases Study formula. 3. Presence of a current Major Depressive Disorder (MDD) based on MINI DSM IV-based criteria 4. Quick Inventory of Depressive Symptomatology-Self-report (QIDS-SR) score of ≥11 at enrollment and ≥11 on QIDS-Clinician Rated (QIDS-C) at randomization. 5. Able to understand and sign informed consent after the nature of the study has been fully explained 1. Unable to understand or give informed consent. 2. Unwilling or unable to participate in the protocol or comply with any of its components 3. Receiving chronic dialysis 4. Kidney transplant recipient 5. Significant hepatic dysfunction or liver enzyme abnormalities 3 times or greater than the upper limit of normal 6. Terminal chronic obstructive pulmonary disease or cancer 7. Presence of seizure disorder 8. Current use of class I anti-arrhythmic medications (such as 1C propafenone and flecanide), pimozide, MAO inhibitors, reserpine, guanethidine, cimetidine, or methyldopa; tri-cyclic anti-depressants, neuroleptics, or anti-convulsants 9. Use of serotonergic drugs or supplements such as triptans, tramadol, linezolid, tryptophan, and St. John's Wort. 10. Use of medications known to cause QT prolongation on EKG 11. Ongoing use of antidepressant medications for depression treatment 12. Past treatment failure on bupropion 13. Initiation of depression-focused psychotherapy in the 3 months prior to study entry 14. Active alcohol or substance abuse or dependence that requires acute detoxification at study entry 15. Present or past psychosis or Bipolar I or II disorder 16. Dementia or a Mini-Mental State Examination score <23 17. Active suicidal intent 18. Pregnancy, lactation, or women of childbearing potential not willing to use adequate contraception

• 18-50y/o; males and females; all races and ethnicities; able to provide written informed consent; able to read, speak, and understand English; medically stable; meeting DSM-IV (SCID-based) criteria for schizophrenia, schizoaffective disorder, or bipolar I disorder with psychotic features (we will use DSM-IV to be consistent with prior B-SNIP samples); PANSS total score of ≥70 and at least one item scored ≥5 or two items scored ≥4 on PANSS Positive Subscale; normal baseline values for absolute neutrophil count (ANC above 1500/mm3)
• premorbid intellectual ability estimate below 70 (WRAT-4, Word Reading subtest, age-corrected standardized score); comorbid DSM-IV diagnosis of alcohol or substance abuse in prior 1 month or substance dependence in prior 3 months; neurological (e.g., seizure disorder, stroke, traumatic brain injury with a loss of consciousness ≥ 30min) or severe medical condition (e.g., decompensated cardiovascular disorder, AIDS) that may affect central nervous system function; concomitant medications known to affect EEG properties (i.e., lithium, anticonvulsants, benzodiazepines) or strong CYP 1A2 inhibitors (e.g., ciprofloxacin, enoxacin) or strong CYP 3A4 inducers (e.g., phenytoin, carbamazepine, phenobarbital, rifampin) which cannot be safely discontinued; vulnerable populations (e.g., pregnant, nursing, incarcerated); unwilling to use reliable means of contraception; history of neuroleptic malignant syndrome; prior treatment with clozapine, prior treatment with long-acting injectable antipsychotics that are 1-month formulations within the past 3 months and for 3-month formulations within the past 6 months; intolerable side effects to either clozapine or risperidone in lifetime, or a previously failed trial of either clozapine or risperidone at adequate doses in lifetime; history of drug reaction with eosinophilia and systemic symptoms syndrome (DRESS), also known as drug-induced hypersensitivity syndrome (DIHS); high risk for suicide defined as more than 1 attempt in past 12 months that required medical attention, any attempt in the past 3 months or current suicidal ideation with plan and intent such that outpatient care is precluded; current homicidal ideation with plan and intent such that outpatient care is precluded.

• Age 60-80, all races/ethnicities, and both sexes are eligible;
• a) A positive family history of dementia defined as having at least one first-degree relative with a history of AD or other type of dementia or
• b) having subjective memory complaints defined as a positive answer to BOTH of the following questions: 1. "Are you worried about your memory or thinking abilities? a) Not at all, b) A little bit, c) A lot"; B and C
•includes 2. "Do you feel you have difficulty with your memory or thinking that is worse than in the past?" b) Yes or No; Yes
•includes
• Mini-Mental State Exam (MMSE) ≥ 26 to exclude gross dementia; based on clinical judgment, may be rescreened in ≥ 7 days;
• Individuals with SBP ≥ 130 and SBP ≤ 180; Those on antihypertensives are eligible. If an individual, not treated for HTN, has a SBP ≥ 125 mmHg, consider rescreening after 24 hours;
• Willingness to be randomized into the treatment groups and ability to return to clinic for follow-up visits over 24 months;
• Fluency in English or Spanish or both, adequate visual and auditory acuity to allow neuropsychological testing;
• Participants must have a regular healthcare provider.
• Clinically documented history of stroke, focal neurological signs or other major cerebrovascular diseases based on clinical judgment or MRI/CT scans such as evidence of infection, infarction, or other brain lesions;
• Diagnosis of AD or other type of dementia, or significant neurologic diseases such as Parkinson's disease, seizure disorder, multiple sclerosis, history of severe head trauma or normal pressure hydrocephalus;
• Evidence of severe major depression (GDS ≥ 12, may be rescreened after 12 weeks or longer if evidence of reactive depression or temporary mood disturbances) or clinically significant psychopathology, (e.g., psychosis and schizophrenia); if hospitalized in past year, can be rescreened in 6 months; or presence of a major psychiatric disorder that in the investigator's opinion, could interfere with adherence to research assessments or procedures.
• Unstable heart disease based on clinical judgment (e.g., heart attack/cardiac arrest, cardiac bypass procedures within previous 6 months and congestive heart failure), or other severe medical conditions;
• History of atrial fibrillation and evidence on ECG with any of the following: active symptoms of persistent palpitation, dizziness, history of syncope, chest pain, dyspnea, orthopnea, shortness of breath at rest, or paroxysmal nocturnal dyspnea within the past 6 months; resting heart rate of < 30 or > 110 bpm; taking class I or III antiarrhythmic drugs including flecainide, propafenone, dronedarone, sotalol, dofetilide, and amiodarone; or clinical concerns for safely participating in lowering blood pressure.
• Systolic BP equal or greater than 180 mmHg and/or diastolic BP equal or greater than 110 mmHg, may be rescreened in 1 week.
• Orthostatic hypotension, defined as the third standing SBP < 100mmHg, may be rescreened after 2 weeks;
• History of significant autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis or polymyalgia rheumatica;
• Significant history of alcoholism or drug abuse within the last five years;
• Uncontrolled diabetes mellitus, defined as hemoglobin A1C > 6.5%, or requiring insulin treatment;
• Clinically diagnosed and untreated sleep apnea;
• Regularly smoking cigarettes within the past year;
• Pacemaker or other medical device of metal that precludes performing MRI;
• Women with a potential for pregnancy, lactation/childbearing (2 year post-menopausal or surgically sterile to be considered not childbearing potential);
• Participant enrolled in another investigational drug or device study, either currently or within the past 2 months;
• Severe obesity with BMI > 40 ; clinical judgment should be applied in all cases to assess patient safety and anticipated compliance;
• Allergy to angiotensin receptor blockers (ARBs), i.e., drugs that have a suffix "-sartan"; allergy to amlodipine;
• Abnormal screening laboratory tests (e.g., liver ALT and AST > 3 x ULN, GFR < 30 or Hct < 28%); may be rescreened after 2 weeks or longer;
• A medical condition likely to limit survival to less than 3 years;
• Participant has any condition(s) judged by the study investigator to be medically inappropriate, risky or likely to cause poor study compliance. For example: 1. Plans to move outside the clinic catchment area in the next 2 years; 2. Significant concerns about participation in the study from spouse, significant other, or family members; 3. Lack of support from primary health care provider; 4. Residence too far from the study clinic site such that transportation is a barrier including persons who require transportation assistance provided by the study clinic funds for screening or randomization visits; 5. Residence in a nursing home; persons residing in an assisted living or retirement community are eligible if they meet the other criteria; 6. Other medical, psychiatric, or behavioral factors that, in the judgment of the site PI or clinician, may interfere with study participation or the ability to follow the study Protocol. 7. Couples or significant partners who live together cannot be enrolled or participate simultaneously in the study.

Key Subjects must meet all of the following key inclusion criteria: 1. Completed written informed consent. 2. Aged 18 to 65 years, inclusive, at the time of informed consent. 3. Diagnosis of MDD meeting the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) and International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10). 4. Subject is currently on stable pharmacological treatment for depression, defined as ≤50% change in dose during the 6 weeks prior to randomization to ≥1 of the oral antidepressant medications listed in the MGH ATRQ. 5. Snaith Hamilton Pleasure Scale (SHAPS) score is ≥30 at screening and Day 1. Key Subjects will be excluded from the study if they meet any of the following key criteria: 1. Any psychiatric disorder disallowed per protocol and electroconvulsive therapy (ECT) within 6 months prior to screening. Comorbid anxiety disorders are not exclusionary. 2. Have a significant risk of suicidal or violent behavior. Subjects with any suicidal ideation of type 4 (active suicidal ideation with some intent to act, without specific plan) or type 5 (active suicidal ideation with specific plan and intent) in the past 12 months before screening based on the C-SSRS or according to the investigator's clinical judgment should be excluded. 3. A history of seizure disorder, stroke, Alzheimer disease, Parkinson disease, multiple sclerosis, head injury associated with loss of consciousness for more than 15 minutes, or other neurodegenerative disorder.

The patient must be in a major depressive disorder (MDD) episode for ≥ two years or have had at least four episodes of MDD, including the current episode. The patient's depressive illness meets a minimum criterion of four prior failed treatments of adequate dose and duration as measured by a tool designed for this purpose. The patient is experiencing a major depressive episode (MDE) as measured by a guideline recommended depression scale assessment tool on two visits, within a 45-day span prior to implantation of the VNS device. Patients must maintain a stable medication regimen for at least four weeks before device implantation. Current or lifetime history of psychotic features in any MDE; Current or lifetime history of schizophrenia or schizoaffective disorder; Current or lifetime history of any other psychotic disorder; Current or lifetime history of rapid cycling bipolar disorder; Current secondary diagnosis of delirium, dementia, amnesia, or other cognitive disorder; Current suicidal intent; or Treatment with another investigational device or investigational drugs.

• Informed consent obtained before any study-related activities. Study-related activities are any procedures that are carried out as part of the study, including activities to determine suitability for the study
• Male or female, age greater than or equal to 18 years at the time of signing informed consent
• Body mass index (BMI) of
• Greater than or equal to 27.0 kg/m^2 with the presence of at least one of the following weight-related complications (treated or untreated): hypertension, dyslipidaemia, obstructive sleep apnoea or cardiovascular (CV) disease OR
• Greater than or equal to 30.0 kg/m^2
• History of at least one self-reported unsuccessful dietary effort to lose body weight
• A self-reported change in body weight greater than 5 kg (11 pound [lbs]) within 90 days before screening irrespective of medical records
• HbA1c greater than or equal to 6.5 percent (48 mmol/mol) as measured by the central laboratory at screening

Criteria for Inclusion of participants: A potential participant will be eligible for participation in this study if the following criteria are met: 1. Male and female adult or youth aged 10 and older of any race or ethnicity. 2. Ability to speak, read, and understand English. However, the parent(s) or legal guardians of minors may either speak English or Spanish as the consenting process can be conducted bilingually. 3. A lifetime or a current diagnosis of a mood disorder based upon a semi-structured diagnostic interview. 4. Adults age 18 and older must be able to provide written informed consent; for youth younger than age 18, a parent or legal guardian must provide written informed consent, and the child or teen must provide written informed assent. Eligibility for Healthy Controls For comparison purposes, potential health control participants who do NOT have a psychiatric diagnosis will be enrolled as part of the healthy control arm of this study. 1. Male and female adult or youth aged 10 and older of any race or ethnicity. 2. Ability to speak, read, and understand English. However, the parent(s) or legal guardians of minors may either speak English or Spanish as the consenting process can be conducted bilingually. 3. Adults age 18 and older must be able to provide written informed consent; for youth younger than age 18, a parent or legal guardian must provide written informed consent, and the child or teen must provide written informed assent. Criteria for Exclusion of Participants A potential participant will NOT be eligible for participation in this study if any of the following criteria are met: 1. History of schizophrenia, schizoaffective disorders or chronic psychotic disorders based upon a semi-structured diagnostic interview. 2. Diagnosis of human immunodeficiency virus (HIV) or hepatitis B or C (human immunodeficiency virus (HIV) testing is not required for this study). 3. Unable to provide a stable home address and contact information. 4. Has any condition for which, in the opinion of the investigator or designee, study participation would not be in their best interest (including but not limited to cognitive impairment, unstable general medical condition, intoxication, active psychosis) or that could prevent, limit, or confound the protocol-specified assessments. 5. Requires immediate hospitalization for psychiatric disorder or suicidal risk as assessed by a licensed study clinician. Eligibility for Healthy Controls A potential Healthy Control participant will NOT be eligible for participation in this study if any of the following criteria are met: 1. A lifetime or a current history of a mood disorder based upon a semi-structured diagnostic interview. 2. Meets any exclusion criteria as part of the main D2K study interview.

• Participant is 22 years of age and older at the time of enrollment
• Participant has been diagnosed with pathogenic deletions or mutations of the SHANK3 gene
• Participant is proficient in English
• Participant provided consent

• Female ASA physical status 1-3 scheduled for open abdominal hysterectomy
• Age 18-80 years old
• Able to participate personally or by legal representative in informed consent in English or Spanish
• History of relevant drug allergy
• Age less than 18 or greater than 80 years
• Chronic opioid use or drug abuse
• Active use of anticoagulant medication
• Significant psychiatric disturbance
• Inability to understand the study protocol
• Refusal to provide written consent

Inclusion Criteria Study participants must: 1. Be adolescents (aged 12-18 years); 2. Have the ability to speak, read, and understand English. The parent(s) or legal guardians of minors must also speak, read and understand English; 3. Be willing to provide consent/assent. Consent will be provided by parents/LAR/guardian for youth under age 18 or by young adult participant, aged 18. Youth, aged 8-17, must be willing to provide assent; 4. Have the ability to complete clinical evaluations and self-report measures; 5. Meet criteria for one of these three groups: 1. Adolescent with suicidal behaviors, defined as having a recent (within 3 months) suicide attempt or suicidal ideation warranting urgent evaluation; 2. Adolescents at risk for mood disorders, defined by either personal history of anxiety disorder or substance use disorder or a history of trauma, or a first degree relative with a history of a mood disorder or suicidal history; 3. Healthy adolescents with no lifetime history of any psychiatric or substance use disorders or a history of trauma. Additionally, no first-degree family member with a history of a mood disorder or suicidal history.. Exclusion Criteria Study participants must not: 1. Have current poorly controlled asthma, acute/chronic infection or other medical condition(s) that may affect immune marker levels; 2. Have a current medication (e.g., corticosteroids) that may affect immune marker levels of reactivity; 3. Have any condition for which, in the opinion of the investigator or designee, study participation would not be in their best interest (including but not limited to cognitive impairment, unstable general medical condition, intoxication, active psychosis) or that could prevent, limit, or confound the protocol-specified assessments; 4. Be unable to provide a stable home address and contact information

• Adolescents and young adults aged 10-24, male and female of all races and ethnicity.
• Participants must be English-speaking (because several study assessments are only available in the English language), however the parent(s) or legal guardian may either speak English or Spanish as the consenting process can be conducted bilingually.
• Adults age 18 and older must be able to provide written informed consent; for youth younger than age 18, a parent or legal guardian must provide written informed consent, and the child or teen must provide written informed assent.
• Ability to complete clinical evaluations and neuropsychological testing.
• Individuals who are unable to provide informed consent.
• Participants who are non-English speaking.
• Individuals with any of the following psychotic features: MDD with psychotic features, schizophrenia, schizoaffective disorder, or other Axis I psychotic disorder.
• Individuals with a depression diagnosis or a history of depression diagnosis at the initial visit (participants who develop depression during the longitudinal follow-up will continue in the study).
• A PHQ-9 score of 10 or greater.
• Individuals who are unable to provide a permanent home address and contact information.
• Individuals with any condition for which, in the opinion of the investigator, study participation would not be in their best interest (e.g., compromise their well-being) or that could prevent, limit, or confound the protocol-specified assessments.