Psychiatry — depression, anxiety, psychotic disorders, SUDs
**Major depressive disorder (DSM-5 SIGECAPS):** Sleep changes, Interest loss (anhedonia), Guilt, Energy, Concentration, Appetite, Psychomotor, Suicidality — ≥5 symptoms ≥2 weeks with at least anhedonia or depressed mood. Tx: SSRI (first-line), SNRI, bupropion, mirtazapine. CBT/IPT equally effective in mild-mod. ECT for severe/catatonic/psychotic; ketamine/esketamine for treatment-resistant.
**Bipolar:** I (≥1 manic), II (hypomania + MDE). Mood stabilizers — lithium (check thyroid, renal, level), valproate, lamotrigine (depressive). Atypical antipsychotics — quetiapine, lurasidone, cariprazine. Antidepressant monotherapy can induce mania.
**Anxiety disorders:** GAD, panic, social, specific phobias. SSRI/SNRI first-line; CBT effective. Benzos short-term only (tolerance, dependence, falls in elderly).
**PTSD:** DSM-5 Criterion A event + intrusion + avoidance + negative cognitions + hyperarousal ≥1 month. Trauma-focused CBT, prolonged exposure, EMDR. SSRI/SNRI. Prazosin for nightmares.
**Schizophrenia:** ≥6 months with ≥1 month active (≥2 of: delusions, hallucinations, disorganized speech/behavior, negative symptoms). Atypicals (risperidone, olanzapine, aripiprazole, clozapine for refractory — ANC monitoring for agranulocytosis). Typicals — EPS, tardive dyskinesia, NMS.
**Substance use disorders (DSM-5):** ≥2 of 11 criteria in 12 months. • **Alcohol** — CIWA-guided taper; naltrexone, acamprosate, disulfiram; thiamine before glucose. • **Opioid** — buprenorphine, methadone, naltrexone; naloxone rescue. • **Tobacco** — varenicline, bupropion, NRT.
**Suicide risk** — SAD PERSONS; mean plan/intent > ideation. Restrict means (firearms, medications). Safety planning intervention and follow-up calls reduce short-term risk.