Psychiatry COMAT Command Center Psychiatry Shelf Exam Command Center

A major depressive episode requires ≥ 5 of 9 SIGECAPS symptoms present nearly every day for ≥ 2 consecutive weeks, representing a change from prior functioning. At least one symptom must be depressed mood or anhedonia (loss of interest/pleasure):

• SIGECAPS Mnemonic: Sleep (insomnia or hypersomnia), Interest (anhedonia), Guilt (worthlessness, excessive guilt), Energy (fatigue), Concentration (impaired decision making), Appetite (weight loss or gain >5% in a month), Psychomotor (retardation or agitation), Suicidal ideation or recurrent thoughts of death.
• Persistent Depressive Disorder (Dysthymia): Depressed mood for ≥ 2 years (≥ 1 year in children/adolescents) with ≥ 2 depressive symptoms; symptom-free intervals never exceed 2 consecutive months.
• Atypical Depression: Mood reactivity (mood brightens in response to positive events) plus ≥ 2 features: leaden paralysis (heavy limbs), hyperphagia/weight gain, hypersomnia, and rejection sensitivity. Historically highly responsive to MAO inhibitors, now treated first-line with SSRIs/CBT.
• MDD with Psychotic Features: Delusions or hallucinations occur only during the depressive episode. Requires combination therapy: Antidepressant + Second-Generation Antipsychotic, or emergent Electroconvulsive Therapy (ECT).
• Grief vs MDD: Normal grief is characterized by waves of sadness ('pangs of grief') focused on memories of the deceased, with preserved self-esteem and humor. MDD features pervasive pervasive unworthiness, persistent nihilism, and active suicidal desire to die rather than simply wanting to reunite with the deceased.

Differentiating bipolar disorder from unipolar depression is critical before initiating pharmacotherapy, as antidepressant monotherapy can precipitate mania or rapid cycling:

• Bipolar I Disorder: Defined by at least ONE manic episode. Depressive episodes are common but not required for diagnosis. Mania: Abnormally elevated, irritable, or expansive mood with increased goal-directed energy lasting ≥ 7 consecutive days (or any duration if hospitalization is required) with ≥ 3 DIGFAST symptoms (≥ 4 if mood is irritable): Distractibility, Impulsivity/indiscretion, Grandiosity, Flight of ideas, Activity increase, Sleep decrease (no need for sleep), Talkativeness (pressured speech). Causes severe functional impairment or psychosis.
• Bipolar II Disorder: At least one hypomanic episode AND at least one major depressive episode. Hypomania: Elevated mood and DIGFAST symptoms for ≥ 4 consecutive days; noticeable change in functioning but no marked social/occupational impairment, no hospitalization, and NO psychosis. If psychosis or hospitalization occurs, it is by definition Bipolar I.
• Cyclothymic Disorder: For ≥ 2 years, numerous periods of hypomanic symptoms and depressive symptoms that never meet full criteria for hypomania or major depression.
• Postpartum Blues: Mild tearfulness, dysphoria, insomnia beginning 2–3 days postpartum and peaking around day 5; self-limited, completely resolving within 14 days. Reassurance and supportive care.
• Postpartum Depression: Meets full MDD criteria; typically begins within 4–6 weeks postpartum (can present up to 12 months). Treat with SSRIs (sertraline preferred in breastfeeding) and psychotherapy.
• Postpartum Psychosis: True medical emergency. Delusions (often infant-focused: infant is possessed, evil, or must be saved), hallucinations, mood lability. Immediate psychiatric hospitalization, antipsychotics, and infant separation until safe; high risk of infanticide and suicide.

The schizophrenia spectrum is structured along a strict temporal progression:

• Brief Psychotic Disorder: Sudden onset of ≥ 1 psychotic symptom (delusions, hallucinations, disorganized speech, grossly disorganized/catatonic behavior) lasting ≥ 1 day but < 1 month, with eventual full return to premorbid baseline functioning. Often triggered by an extreme psychosocial stressor.
• Schizophreniform Disorder: Meets criteria for schizophrenia, with total duration (including prodromal, active, and residual phases) lasting ≥ 1 month but < 6 months. Social/occupational decline is common but not strictly required.
• Schizophrenia: Continuous signs of disturbance for ≥ 6 months, including at least 1 month of active phase symptoms (≥ 2 of: delusions, hallucinations, disorganized speech, disorganized behavior, negative symptoms; at least one must be delusions, hallucinations, or disorganized speech). Must cause marked decline in social, occupational, or self-care functioning.
• Schizoaffective Disorder: An uninterrupted period of illness during which there is a major mood episode (depressive or manic) concurrent with active symptoms of schizophrenia, PLUS delusions or hallucinations for ≥ 2 consecutive weeks in the ABSENCE of prominent mood symptoms. This critical rule differentiates it from MDD or Bipolar with psychotic features (where psychosis occurs exclusively during mood episodes).
• Delusional Disorder: Presence of ≥ 1 delusion lasting ≥ 1 month in an individual whose functioning is otherwise not markedly impaired and behavior is not bizarre. No other psychotic symptoms (no prominent hallucinations, no disorganized speech). Common subtypes: Persecutory, Erotomanic, Jealous, Somatic, Grandiose.

Before diagnosing a primary psychiatric illness, medical, neurological, and toxicological causes must be systematically excluded:

• Substance/Medication-Induced Psychosis: Cocaine/amphetamines (tactile hallucinations/formication, paranoia, mydriasis), Phencyclidine (PCP: rotary nystagmus, violent agitation), High-dose corticosteroids ('steroid psychosis': mania, depression, delusions), Anticholinergics (delirium, visual hallucinations).
• Anti-NMDA Receptor Encephalitis: Young female presenting with acute psychiatric symptoms (psychosis, paranoia, catatonia, agitation) rapidly progressing to autonomic instability, seizures, hypoventilation, and choreoathetosis. Highly associated with ovarian teratomas. Workup: CSF anti-NMDA receptor antibodies and pelvic ultrasound.
• Creutzfeldt-Jakob Disease (CJD): Rapidly progressive dementia accompanied by behavioral changes, visual hallucinations, and startle-induced myoclonus. Biopsy/autopsy demonstrates extensive spongiform vacuolation of the cerebral cortex without inflammation. CSF positive for 14-3-3 protein and RT-QuIC. EEG demonstrates periodic sharp wave complexes (PSWCs).
• Wilson Disease: Hepatolenticular degeneration due to ATP7B mutation causing toxic copper accumulation in basal ganglia. Neuropsychiatric symptoms (depression, psychosis, personality change, tremor, dysarthria) with Kayser-Fleischer rings and low serum ceruloplasmin.

Antipsychotics act primarily via dopamine D2 receptor blockade, resulting in characteristic efficacy profiles and adverse reactions:

• First-Generation (Typical) Antipsychotics (Haloperidol, Fluphenazine, Chlorpromazine): High-potency agents (haloperidol, fluphenazine) strongly block D2 receptors in the striatum, carrying high risks of Extrapyramidal Symptoms (EPS) and hyperprolactinemia (galactorrhea, amenorrhea, gynecomastia). Low-potency agents (chlorpromazine, thioridazine) have lower EPS but high histaminergic (sedation), alpha-1 (orthostatic hypotension), and anticholinergic (dry mouth, constipation) effects. Chlorpromazine causes corneal deposits; thioridazine causes retinal deposits / retinitis pigmentosa.
• Second-Generation (Atypical) Antipsychotics (Risperidone, Olanzapine, Quetiapine, Aripiprazole, Clozapine): Dual D2 and 5-HT2A receptor antagonism. Lower EPS risk but carry significant metabolic syndrome risk (weight gain, dyslipidemia, hyperglycemia). Olanzapine and clozapine carry highest metabolic risk; aripiprazole (D2 partial agonist) and ziprasidone carry lowest. Ziprasidone requires ECG monitoring for QT prolongation.
• EPS Timeline & Management:
  • Acute Dystonia (Hours to Days): Sustained involuntary muscle contractions (torticollis, oculogyric crisis, opisthotonos, laryngospasm). Treatment: Benztropine (anticholinergic) or Diphenhydramine IV/IM.
  • Akathisia (Days to Weeks): Subjective inner restlessness, inability to sit still, pacing. Treatment: First-line is Beta-blocker (Propranolol); alternatives include benzodiazepines (lorazepam) or benztropine.
  • Parkinsonism (Weeks to Months): Bradykinesia, resting pill-rolling tremor, cogwheel rigidity, masked facies. Treatment: Benztropine or Amantadine (dopamine agonist; avoid levodopa as it exacerbates psychosis).
  • Tardive Dyskinesia (Months to Years): Involuntary choreoathetoid movements of face, mouth, tongue (lip smacking, tongue protrusion, grimacing) due to D2 receptor upregulation/supersensitivity. Often irreversible. Treatment: Discontinue or switch to Clozapine or Quetiapine; initiate VMAT2 inhibitors (Valbenazine, Deutetrabenazine). Anticholinergics worsen tardive dyskinesia.
• Clozapine Protocols: Highly effective for treatment-resistant schizophrenia (failure of ≥ 2 antipsychotics) and reduces suicide risk. Mandatory absolute neutrophil count (ANC) monitoring due to risk of agranulocytosis. Baseline ANC must be ≥ 1500/µL (≥ 1000 in benign ethnic neutropenia); hold clozapine if ANC drops < 1000/µL. Other risks: myocarditis, paralytic ileus, seizures.

Differentiating life-threatening psychiatric emergencies on board exams:

• Neuroleptic Malignant Syndrome (NMS): Idiosyncratic reaction to dopamine antagonists (antipsychotics, metoclopramide) or withdrawal of dopamine agonists (levodopa). Features: Severe 'lead-pipe' muscle rigidity, extreme hyperthermia (> 40°C), autonomic instability (labile BP, tachycardia, diaphoresis), altered mental status, and marked elevated creatine kinase (CK) and leukocytosis. Reflexes: Hyporeflexia / normal reflexes. Treatment: Discontinue offending agent immediately, aggressive IV fluids, cooling blankets, and pharmacotherapy: Dantrolene (ryanodine receptor blocker) or Bromocriptine (dopamine agonist).
• Serotonin Syndrome: Excess serotonergic activity (SSRIs + MAOIs, TCAs, Tramadol, Linezolid, MDMA/Ecstasy, St. John's Wort). Features: Hyperthermia, autonomic instability, agitation, gastrointestinal distress (diarrhea, hyperactive bowel sounds), and neuromuscular excitability: Tremor, Hyperreflexia, and Spontaneous/Inducible Clonus. Treatment: Discontinue serotonergic drugs, supportive care, benzodiazepines; antidote for severe cases is Cyproheptadine (5-HT2 receptor antagonist).
• Lithium Monitoring & Toxicity: Narrow therapeutic index (0.6–1.2 mEq/L). Cleared exclusively by the kidneys; thiazide diuretics, NSAIDs, and ACE inhibitors reduce renal clearance and trigger acute toxicity. Toxicity (> 1.5 mEq/L): Coarse tremor, ataxia, confusion, seizures, arrhythmias. Hemodialysis indicated if level > 4.0 mEq/L or > 2.5 with severe neurotoxicity. Adverse effects: nephrogenic diabetes insipidus, hypothyroidism, Ebstein anomaly in utero.

Differentiating anxiety presentations on the clerkship examination:

• Panic Disorder: Recurrent, unexpected panic attacks (discrete surges of intense fear peaking within minutes with palpitations, sweating, trembling, dyspnea, chest pain, fear of dying or losing control). At least one attack must be followed by ≥ 1 month of persistent worry about additional attacks or maladaptive behavior changes (avoidance). First-line treatment: SSRIs/SNRIs + Cognitive Behavioral Therapy (CBT). Benzodiazepines only for acute panic abortive therapy; avoid long-term use.
• Agoraphobia: Marked, disproportionate fear or anxiety about ≥ 2 situations where escape might be difficult or help unavailable in the event of panic or embarrassing symptoms: public transportation, open spaces, enclosed spaces, standing in line/crowds, or being outside of home alone. Lasts ≥ 6 months. Treated with CBT and SSRIs.
• Generalized Anxiety Disorder (GAD): Excessive, uncontrollable anxiety and worry about multiple everyday domains lasting ≥ 6 months, accompanied by ≥ 3 symptoms (restlessness, fatigue, difficulty concentrating, irritability, muscle tension, sleep disturbance). First-line: SSRIs/SNRIs and CBT; Buspirone (5-HT1A partial agonist) is a non-sedating, non-addictive second-line alternative.
• Social Anxiety Disorder (Social Phobia): Marked fear of scrutiny or negative evaluation by others in social situations (conversations, eating in public, speaking). If limited exclusively to public speaking/performances: Performance-Only Subtype (treated with as-needed Beta-blockers [Propranolol] or benzodiazepines 30-60 min prior to event). Generalized social anxiety is treated with SSRIs and CBT.

Trauma- and stress-related conditions have strict diagnostic cutoff periods:

• Acute Stress Disorder (ASD): Exposure to actual or threatened death, serious injury, or sexual violence, resulting in intrusion symptoms, negative mood, dissociation, avoidance, and arousal lasting ≥ 3 days to ≤ 1 month post-trauma. First-line therapy is trauma-focused CBT; pharmacotherapy is generally not indicated initially.
• Post-Traumatic Stress Disorder (PTSD): Same trauma exposure criteria as ASD, but symptoms persist for > 1 month, causing significant functional distress. Four symptom clusters: (1) Intrusive memories/flashbacks/nightmares, (2) Avoidance of trauma reminders, (3) Negative alterations in cognitions and mood (detachment, persistent negative emotional state), and (4) Hyperarousal (hypervigilance, exaggerated startle, insomnia). First-line: Trauma-focused CBT and SSRIs (Sertraline, Paroxetine). Prazosin (alpha-1 blocker) is highly effective for trauma-related nightmares and sleep disruption.
• Obsessive-Compulsive Disorder (OCD): Presence of obsessions (intrusive, recurrent distressing thoughts/urges) and/or compulsions (repetitive behaviors or mental acts performed to neutralize anxiety according to rigid rules). Time-consuming (>1 hour/day). First-line: Exposure and Response Prevention (ERP) CBT and high-dose SSRIs; Clomipramine (TCA) is second-line.

Alcohol withdrawal represents a potentially fatal autonomic hyperreactivity syndrome resulting from chronic down-regulated GABA and up-regulated NMDA receptors:

• Mild Withdrawal (6–12 hours): Tremor ('shakes'), anxiety, tachycardia, hypertension, diaphoresis, insomnia, nausea/vomiting. Sensorium remains clear.
• Alcoholic Hallucinosis (12–48 hours): Visual, auditory, or tactile hallucinations with intact orientation and vital signs. Resolves within 48 hours.
• Withdrawal Seizures (12–48 hours): Generalized tonic-clonic seizures, often occurring as single or clustered convulsions.
• Delirium Tremens (DTs) (48–96 hours): Medical emergency with 5% mortality. Severe delirium (gross confusion, disorientation, agitation), autonomic instability (marked tachycardia, hypertension, severe fever/hyperthermia), and diaphoresis.
• Management: Symptom-triggered protocolized Benzodiazepines (Lorazepam, Diazepam, or Chlordiazepoxide) based on CIWA-Ar scores. In patients with liver cirrhosis or hepatic failure, use agents without oxidative hepatic metabolism: Lorazepam, Oxazepam, Temazepam (LOT). Administer IV Thiamine (Vitamin B1) BEFORE or alongside glucose to prevent precipitating acute Wernicke encephalopathy (triad: confusion, ataxia, ophthalmoplegia/nystagmus).
• Relapse Prevention Pharmacotherapy: Naltrexone (mu-opioid receptor antagonist; reduces cravings and heavy drinking days; contraindicated in acute hepatitis, liver failure, or current opioid use). Acamprosate (NMDA receptor modulator; maintains abstinence; safe in liver disease; contraindicated if severe renal impairment eGFR < 30). Disulfiram (aldehyde dehydrogenase inhibitor; causes severe flushing, nausea, vomiting with alcohol consumption; requires high adherence).

Differentiating acute overdose and withdrawal syndromes across major drug classes:

• Opioid Intoxication vs Withdrawal: Intoxication presents with the classic triad of respiratory depression, pinpoint pupils (miosis), and CNS depression. Hypoactive bowel sounds, bradycardia, hypothermia. Reversal: Naloxone (IV/IN). Opioid withdrawal: Pupil dilation (mydriasis), piloerection ('cold turkey'), yawning, rhinorrhea, lacrimation, diarrhea, abdominal cramping. Uncomfortable but non-life-threatening. Treatment: Methadone, Buprenorphine, or Clonidine (for autonomic hyperactivity).
• Cocaine & Amphetamine Toxicity: Sympathomimetic excess: pupillary dilation, tachycardia, severe hypertension, diaphoresis, hyperthermia, paranoia, tactile hallucinations (formication/cocaine bugs), chest pain/coronary vasospasm. Treatment: Benzodiazepines are first-line. Avoid pure beta-blockers (e.g., propranolol) due to theoretical unopposed alpha-1 adrenergic stimulation exacerbating coronary vasoconstriction and malignant hypertension.
• Phencyclidine (PCP) Intoxication: Violent behavior, severe agitation, impulsivity, loss of pain sensation, and pathognomonic rotary/multidirectional nystagmus. Treatment: Low-stimulation environment, Benzodiazepines, Haloperidol.

Core neurodevelopmental disorders and diagnostic parameters:

• Attention-Deficit/Hyperactivity Disorder (ADHD): Inattention and/or hyperactivity-impulsivity presenting before age 12, causing clear impairment in ≥ 2 distinct settings (home, school, social). Subtypes: Inattentive, Hyperactive-Impulsive, Combined. First-line therapy for preschool children (4-5 years) is behavioral therapy. First-line for school-age (≥ 6 years) is Stimulant medication (Methylphenidate, Dextroamphetamine). Non-stimulant alternatives: Atomoxetine (selective norepinephrine reuptake inhibitor; preferred in substance abuse history or tics) or Alpha-2 agonists (Guanfacine, Clonidine).
• Autism Spectrum Disorder (ASD): Persistent deficits in social communication/interaction (poor eye contact, lack of social-emotional reciprocity, delayed speech) across multiple contexts, combined with restricted, repetitive patterns of behavior, interests, or activities (hand flapping, lining up toys, rigid adherence to routines). Symptoms present in early developmental period. Comprehensive early intervention with Applied Behavior Analysis (ABA) is standard of care. Second-generation antipsychotics (Risperidone, Aripiprazole) are FDA-approved for severe irritability/aggression.
• Tourette Syndrome: Both multiple motor tics (eye blinking, head jerking, shoulder shrugging) AND at least one vocal tic (grunting, throat clearing, coprolalia) present for > 1 year with onset before age 18. High comorbidity with ADHD and OCD. First-line: Comprehensive Behavioral Intervention for Tics (CBIT). Pharmacotherapy: Alpha-2 agonists (Guanfacine, Clonidine); atypical antipsychotics (Aripiprazole) for refractory cases.

Pediatric behavioral trajectories and syndromic associations:

• Oppositional Defiant Disorder (ODD): Pattern of angry/irritable mood, argumentative/defiant behavior, or vindictiveness lasting ≥ 6 months toward authority figures. Crucial distinction: Does NOT violate fundamental rights of others or major age-appropriate societal norms. First-line: Parent Management Training (PMT).
• Conduct Disorder (CD): Repetitive, persistent pattern violating the basic rights of others or societal norms: aggression to people/animals (cruelty, fighting), destruction of property (fire setting), deceitfulness/theft, serious violations of rules (truancy, running away). If patient is ≥ 18 years, the diagnosis transitions to Antisocial Personality Disorder (which requires evidence of Conduct Disorder with onset before age 15).
• Separation Anxiety Disorder: Developmentally inappropriate fear or anxiety concerning separation from attachment figures lasting ≥ 4 weeks in children/adolescents (≥ 6 months in adults). Often manifests as somatic complaints (headache, stomachache) on school mornings.
• Tuberous Sclerosis Complex (TSC): Autosomal dominant mutation in TSC1 (hamartin) or TSC2 (tuberin). High rate of intellectual disability, autism, and infantile spasms. Cutaneous hallmarks: Ash-leaf hypopigmented macules (visible on Wood's lamp), shagreen patches, facial angiofibromas. Cardiac rhabdomyomas and renal angiomyolipomas.

Differentiating eating disorders requires calculating BMI and assessing compensatory behaviors:

• Anorexia Nervosa: Restriction of energy intake leading to significantly low body weight (BMI < 18.5 kg/m² in adults), intense fear of gaining weight, and distorted body image. Subtypes: Restricting type and Binge-eating/purging type. Physical findings: Lanugo, bradycardia, hypotension, amenorrhea, leukopenia. Hospitalization criteria: HR < 40 bpm, BP < 80/60, orthostasis, cardiac arrhythmia, BMI < 15. First-line therapy: Nutritional rehabilitation and psychotherapy. Avoid bupropion (lowers seizure threshold in eating disorders).
• Refeeding Syndrome: Occurs when carbohydrate feeding is re-introduced in severely malnourished patients. Carbohydrates stimulate insulin release, driving potassium, magnesium, and phosphate into cells to synthesize ATP. Results in severe hypophosphatemia, hypokalemia, and hypomagnesemia, leading to cardiac arrhythmias, heart failure, seizures, rhabdomyolysis, and death. Management: Slow caloric advancement with frequent electrolyte monitoring.
• Bulimia Nervosa: Recurrent episodes of binge eating followed by inappropriate compensatory behaviors (self-induced vomiting, laxative abuse, excessive exercise) at least once weekly for ≥ 3 months. BMI is normal or overweight (BMI ≥ 18.5). Physical signs: Russell sign (dorsal hand calluses from knuckles hitting teeth), parotid gland enlargement, dental enamel erosion. Laboratory: Hypokalemic hypochloremic metabolic alkalosis. First-line pharmacotherapy: Fluoxetine (FDA-approved for bulimia) + CBT.
• Binge-Eating Disorder: Recurrent binge eating without compensatory behaviors. Most common eating disorder; associated with obesity. First-line: CBT; pharmacotherapy includes Lisdexamfetamine (Vyvanse) or topiramate.

Somatic symptom presentations and personality clusters:

• Somatic Symptom Disorder: ≥ 1 somatic symptom (pain, fatigue) that causes significant distress or disruption, with excessive, disproportionate thoughts, anxiety, and time devoted to the symptoms for ≥ 6 months. Management: Regularly scheduled appointments with a single primary care physician.
• Illness Anxiety Disorder: Preoccupation with having or acquiring a serious, undiagnosed illness; somatic symptoms are absent or minimal. High level of health anxiety ('hypochondriasis').
• Conversion Disorder (Functional Neurological Symptom Disorder): Neurological symptoms (blindness, paralysis, non-epileptic seizures) that are incompatible with recognized neurological pathways. Often precipitated by psychological conflict. Classical sign: La belle indifférence (striking lack of concern). Positive Hoover sign (hip extension weakness that normalizes with contralateral hip flexion against resistance).
• Factitious Disorder vs Malingering: Factitious disorder (Munchausen): falsification of symptoms to assume the sick role (primary internal gain; no external incentive). Malingering: intentional falsification of symptoms for secondary external gain (financial compensation, avoiding military duty, evading criminal prosecution, obtaining narcotics).
• Personality Disorders:
  • Cluster A (Weird / Eccentric): Paranoid (distrust, suspicion), Schizoid (social detachment, prefers being alone, indifferent to praise/criticism), Schizotypal (magical thinking, ideas of reference, eccentric appearance).
  • Cluster B (Wild / Dramatic): Antisocial (disregard for rights of others, criminal behavior, lack of remorse, age ≥ 18), Borderline (splitting, unstable relationships, intense abandonment fear, suicidal threats, emptiness; dialectical behavior therapy [DBT]), Histrionic (attention-seeking, provocative, dramatic), Narcissistic (grandiosity, lack of empathy, entitlement).
  • Cluster C (Worried / Fearful): Avoidant (hypersensitive to rejection, desires relationships but avoids due to fear of criticism), Dependent (submissive, needs others to assume responsibility), Obsessive-Compulsive Personality (perfectionism, orderliness, control, ego-syntonic).

Candidates must clearly differentiate clinical capacity from judicial competency:

• Decision-Making Capacity: A clinical determination made by the treating physician for a specific decision at a specific time. A patient with psychiatric illness (schizophrenia, depression) or early dementia can still have capacity if they meet four core components: (1) Communicate a choice (clear, consistent decision), (2) Understand the relevant medical information and options, (3) Appreciate the situation and consequences of their decision on their own health, (4) Rational reasoning (manipulate information logically to arrive at the decision).
• Competency: A legal status determined exclusively by a judge in a court of law.
• Involuntary Psychiatric Commitment: Criteria: Patient has a diagnosed mental illness AND represents an imminent danger to self, an imminent danger to others, or is gravely disabled (unable to provide food, clothing, shelter for basic survival). Involuntary admission does not require patient consent and overrides refusal.
• Tarasoff Duty: When a patient makes a credible, specific, and imminent threat to inflict serious bodily harm against an identifiable third party, the physician has a legal duty to warn and protect the intended victim and notify law enforcement. Confidentiality is legally breached.

Differentiating acute cognitive disturbance from chronic progressive neurocognitive decline:

• Delirium: Acute onset (hours to days), fluctuating course, prominent disturbance in attention, alertness, and arousal, sleep-wake cycle reversal, visual hallucinations common. Reversible once underlying cause (infection [UTI, pneumonia], electrolyte abnormality, medications [anticholinergics, benzos], withdrawal) is corrected. EEG shows diffuse background slowing. First-line management: treat underlying cause and environmental modifications; avoid restraints; low-dose haloperidol only if dangerous agitation.
• Major Neurocognitive Disorder (Dementia): Insidious onset (months to years), progressive decline in memory/executive functioning with preserved alertness and attention until terminal stages.
• Alzheimer Disease: Most common dementia. Early episodic memory loss followed by visuospatial and language deficits. Neuropathology demonstrates extracellular beta-amyloid senile plaques (cleaved from amyloid precursor protein [APP] on chromosome 21) and intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein. Treatment: Acetylcholinesterase inhibitors (Donepezil, Rivastigmine, Galantamine) and NMDA receptor antagonist (Memantine).
• Dementia with Lewy Bodies (DLB): Triad of visual hallucinations, fluctuating cognition, and spontaneous parkinsonism (rigidity, bradykinesia). Pathology: alpha-synuclein intracellular inclusions (Lewy bodies) in basal ganglia and cortex. Extreme neuroleptic sensitivity: typical antipsychotics cause irreversible rigidity and fatal autonomic collapse.
• Frontotemporal Dementia (Pick Disease): Early behavioral disinhibition, hyperorality, apathy, and personality change preceding memory loss. Pick bodies (tau inclusions) and knife-like frontotemporal lobar atrophy.