Adult Psychiatric Disorders

Mood Disorders

Major Depressive Disorder (MDD)

Prevalence ~8% adultsF > M 2:1

DSM-5 Criteria

≥5 symptoms for ≥2 weeks, one of which is depressed mood OR anhedonia. Remember SIG-E-CAPS:

Sleep disturbance (insomnia or hypersomnia)
Interest / pleasure loss (anhedonia)
Guilt / worthlessness
Energy loss / fatigue
Concentration impaired
Appetite / weight change
Psychomotor agitation or retardation
Suicidal ideation

Specifiers

With melancholic features — severe anhedonia, diurnal variation (worse AM), early awakening, psychomotor changes, weight loss, guilt
With atypical features — mood reactivity, hypersomnia, hyperphagia, leaden paralysis, rejection sensitivity (responds best to MAOIs historically)
With psychotic features — mood-congruent delusions (guilt, poverty, nihilism); needs antipsychotic + antidepressant or ECT
With peripartum onset — during pregnancy or within 4 weeks postpartum
With seasonal pattern — light therapy 10,000 lux first-line

Workup (rule out medical causes)

CBC, CMP, TSH, B12/folate, vitamin D
Urine drug screen, RPR if risk factors
PHQ-9 (≥10 moderate, ≥15 severe, ≥20 very severe)
Always screen suicidality (C-SSRS)

Bipolar Disorder

Type I vs II

Type	Mania	Hypomania	Depression
Bipolar I	≥1 manic episode (≥7 days or hospitalized)	—	Usually present, not required
Bipolar II	Never	≥1 hypomanic (≥4 days)	≥1 major depressive episode required
Cyclothymic	Subthreshold up & down for ≥2 yr	—	—

Mania Criteria — DIG FAST

Distractibility
Impulsivity / Indiscretion
Grandiosity
Flight of ideas
Activity increased (goal-directed)
Sleep ↓ (without fatigue)
Talkativeness / pressured speech

🏥 Clinical ActionNEVER start an antidepressant alone in bipolar — risk of precipitating mania ("switch"). Always pair with mood stabilizer. Screen every depressed patient for past manic/hypomanic episodes with MDQ before prescribing SSRI.

Persistent Depressive Disorder (Dysthymia)

Depressed mood most days for ≥2 years (≥1 yr in children), with ≥2 other symptoms. Chronic, lower-grade — but high comorbidity with MDD ("double depression").

Anxiety Disorders

Generalized Anxiety Disorder (GAD)

Excessive worry about multiple events, difficult to control, ≥6 months, with ≥3 somatic symptoms (in adults): restlessness, fatigue, ↓ concentration, irritability, muscle tension, sleep disturbance.

Tx: CBT + SSRI or SNRI (duloxetine, venlafaxine). Buspirone is adjunct. Benzos short-term only.

Panic Disorder

Recurrent unexpected panic attacks + ≥1 month of worry about future attacks or behavioral change (avoidance).

Panic Attack Criteria

Abrupt surge of intense fear peaking within minutes, with ≥4 of: palpitations, sweating, trembling, SOB, choking sensation, chest pain, nausea, dizziness, chills/heat, paresthesias, derealization, fear of losing control, fear of dying.

Tx: CBT (panic-focused) + SSRI/SNRI. Benzo bridge during SSRI titration for severe.

🎯 Board PearlFirst panic attack — rule out MI, PE, hyperthyroidism, pheochromocytoma, substance use (cocaine, caffeine), withdrawal. ECG + basic labs + TSH at minimum.

Specific Phobia

Marked fear of a specific object/situation (animals, heights, blood-injection-injury, situational). Exposure therapy is definitive treatment.

OCD & Related Disorders

Disorder	Hallmark
OCD	Obsessions + compulsions, ≥1 hr/day
Body Dysmorphic Disorder	Preoccupation with perceived physical defect
Hoarding Disorder	Persistent difficulty discarding possessions
Trichotillomania	Recurrent hair-pulling
Excoriation	Skin-picking disorder

Tx: CBT with Exposure & Response Prevention (ERP) is first-line. SSRIs (often high-dose — fluoxetine 60–80 mg, sertraline 200 mg) or clomipramine second-line. N-acetylcysteine has evidence for trichotillomania.

Trauma- and Stressor-Related Disorders

PTSD Criteria (DSM-5, ≥1 month)

Exposure to actual/threatened death, serious injury, or sexual violence
Intrusion — flashbacks, nightmares, intrusive memories
Avoidance — of trauma-related stimuli
Negative cognition / mood — shame, estrangement, anhedonia
Hyperarousal — hypervigilance, startle, irritability, sleep disturbance

Duration	Diagnosis
< 3 days	Acute stress reaction (normal)
3 days – 1 month	Acute Stress Disorder
> 1 month	PTSD
After stressor, < 3 months onset, doesn't meet full criteria	Adjustment Disorder

Treatment

First-line psychotherapy: Trauma-focused CBT, Prolonged Exposure, EMDR, CPT
First-line meds: SSRIs (sertraline and paroxetine are FDA-approved), venlafaxine
Prazosin for nightmares (α1 antagonist)
Avoid: benzodiazepines (worsen long-term outcome, ↑ dependence risk)

Psychotic Disorders

Duration-Based Classification

Duration	Diagnosis
< 1 month	Brief Psychotic Disorder
1–6 months	Schizophreniform
> 6 months	Schizophrenia
Psychotic + mood episodes; psychotic sx for ≥2 wk WITHOUT mood sx	Schizoaffective
Nonbizarre delusions, ≥1 month, function preserved	Delusional Disorder

Schizophrenia — Symptom Domains

Positive: hallucinations (auditory most common), delusions, disorganized speech/behavior
Negative: affective flattening, alogia, avolition, anhedonia, asociality (5 A's)
Cognitive: working memory, executive deficits
Mood: depression, suicidality (lifetime suicide risk ~5%)

Key Epidemiology

Onset: late teens to mid-20s (M); 20s–30s (F)
M = F incidence; worse prognosis in M
Genetic: ~50% concordance in monozygotic twins; ~10% if one first-degree relative

🧠 Mnemonic5 A's of negative symptoms: Affective flattening, Alogia (poverty of speech), Avolition (lack of motivation), Anhedonia, Asociality. Negative sx tend to respond poorly to typical antipsychotics — atypicals do better.

Personality Disorders

Enduring pattern of inner experience and behavior deviating from cultural expectation, pervasive, inflexible, onset in adolescence/early adulthood, causing distress/impairment.

Cluster	Theme	Disorders
A — "Weird"	Odd, eccentric	Paranoid, Schizoid, Schizotypal
B — "Wild"	Dramatic, erratic	Antisocial, Borderline, Histrionic, Narcissistic
C — "Worried"	Anxious, fearful	Avoidant, Dependent, Obsessive-Compulsive PD

Highest-Yield Features

Borderline: splitting, identity disturbance, fear of abandonment, self-harm, chronic emptiness. Tx: DBT (dialectical behavior therapy) — gold standard.
Antisocial: ≥18 yr, hx of conduct disorder before 15; disregard for others' rights
Narcissistic: grandiosity, need for admiration, lack of empathy
OCPD (different from OCD): perfectionism, rigidity, control — ego-syntonic (patient doesn't mind); OCD is ego-dystonic

🎯 Board PearlBorderline = "splitting" (all-good vs. all-bad views) + fear of abandonment + self-harm. DBT is first-line — medications treat comorbid symptoms (mood instability, impulsivity) but aren't curative.

Somatic Symptom & Related Disorders

Disorder	Feature
Somatic Symptom Disorder	Excessive thoughts/feelings about somatic symptoms ≥6 mo
Illness Anxiety Disorder	Preoccupation with having illness despite few/no symptoms
Functional Neurologic (Conversion)	Neuro sx incompatible with disease; often after stressor
Factitious Disorder	Intentional fabrication/induction for sick role (no external gain)
Malingering	Intentional fabrication for external gain (not a psych disorder)

Dissociative Disorders

Dissociative Amnesia — inability to recall autobiographical info, usually trauma-related
Dissociative Identity Disorder (DID) — ≥2 distinct personality states; usually severe childhood trauma
Depersonalization / Derealization — persistent sense of detachment from self or surroundings

Substance Use Disorders

DSM-5 uses 11 criteria across 4 groups (impaired control, social impairment, risky use, pharmacologic — tolerance/withdrawal). Severity: mild 2–3, moderate 4–5, severe ≥6 criteria in 12 months.

Substance	Intoxication	Withdrawal	Tx
Alcohol	Disinhibition, slurred speech, ataxia	Tremor → seizure (24–48 h) → DTs (48–96 h, ~15% mortality untreated)	Benzos (taper), thiamine BEFORE glucose; naltrexone, acamprosate, disulfiram
Opioids	Pinpoint pupils, respiratory depression, euphoria	Piloerection, rhinorrhea, myalgia, diarrhea — uncomfortable NOT dangerous	Naloxone (acute); buprenorphine, methadone, naltrexone for MOUD
Stimulants (cocaine, meth)	Mydriasis, HTN, agitation, hyperthermia, psychosis	Dysphoria, hypersomnia, hyperphagia, craving	Supportive; benzos for agitation
Cannabis	Red eyes, dry mouth, ↑ appetite, impaired memory	Irritability, insomnia, dysphoria	CBT, motivational interviewing
Benzodiazepines	Sedation, ataxia, resp depression (esp w/ alcohol/opioids)	Like alcohol: tremor, seizure, death possible	Slow taper; flumazenil (risky — can cause seizure)
Hallucinogens (LSD, psilocybin)	Perceptual changes, mydriasis, ↑ HR/BP	None significant	Supportive, "talk down," benzo for agitation
PCP	Vertical/horizontal nystagmus, violence, analgesia	None significant	Benzos, antipsychotics, safety

🏥 Wernicke-KorsakoffAlcohol use disorder → thiamine deficiency → Wernicke's (acute, reversible): confusion, ataxia, ophthalmoplegia. Untreated → Korsakoff's (chronic, irreversible): anterograde amnesia + confabulation. Give IV thiamine BEFORE glucose to prevent precipitating Wernicke's.

Psychiatric Emergencies

Suicide Risk Factors — "SAD PERSONS"

Sex (male)
Age (<19 or >45)
Depression
Previous attempt
Ethanol/substance use
Rational thinking loss (psychosis)
Social support lacking
Organized plan
No spouse / single
Sickness (chronic illness)

Most completed suicides: men, older adults, firearms. Always ask directly — asking does NOT increase risk.

Neuroleptic Malignant Syndrome (NMS)

Idiosyncratic reaction to D2 blockade. Tetrad: "FEVER" — Fever (hyperthermia), Encephalopathy, Vitals unstable, Enzyme ↑ (CK), Rigidity ("lead pipe").

Tx: Stop antipsychotic, aggressive cooling & IVF, dantrolene, bromocriptine; ICU.

Serotonin Syndrome vs NMS

Feature	Serotonin Syndrome	NMS
Onset	Hours	Days–weeks
Reflexes	Hyperreflexia, clonus	Bradyreflexia, rigidity (lead-pipe)
Pupils	Mydriasis	Normal
Trigger	Serotonergic drug	D2 antagonist (or rapid levodopa withdrawal)
Tx	Cyproheptadine, supportive	Dantrolene, bromocriptine, supportive

Lithium Toxicity

Narrow therapeutic index (0.6–1.2 mEq/L). Toxicity: coarse tremor, ataxia, confusion, seizures, nephrogenic DI. Triggers: dehydration, NSAIDs, ACEIs, thiazides. Hemodialysis if level > 4.0 or severe symptoms.

🧠 MnemonicNMS = "FEVER + LEAD PIPE". Serotonin syndrome = "SHIVERS" — Shivering, Hyperreflexia, Increased temperature, Vital signs unstable, Encephalopathy, Restlessness, Sweating.