Psychiatry · Psychotic Disorders
The facts most likely to be tested
Press 1–5 to rate · ↑↓ to navigate
Diagnosis requires characteristic symptoms for more than 6 months; schizophreniform is 1 to 6 months and brief psychotic disorder is >1 day to <1 month.
Combines positive symptoms (delusions, hallucinations, disorganized speech) with negative symptoms (flat affect, avolition, social withdrawal).
Atypical antipsychotics are first-line; hospitalize acutely psychotic patients for safety.
Clozapine is the most effective drug for treatment-resistant disease (after >= 2 failed trials) but requires regular CBC monitoring for agranulocytosis.
Always obtain a urine drug screen to exclude cocaine/amphetamine-induced psychosis and rule out other organic causes.
Driven by dysregulated dopamine: mesolimbic hyperactivity causes positive symptoms, mesocortical hypoactivity causes negative symptoms.
Watch for extrapyramidal effects and neuroleptic malignant syndrome (treat with dantrolene or bromocriptine); avoid olanzapine in metabolic-risk patients.
Vignette unlocked
A 22-year-old man is brought in by family for 8 months of worsening behavior. He believes the government is broadcasting messages through his television and hears voices commenting on his actions. His speech is tangential, his affect is flat, and he has stopped bathing or attending school. There is no history of mood episodes, and a urine drug screen is negative.
Which of the following is the most likely diagnosis?
Schizophrenia.
Positive symptoms (delusions, auditory hallucinations, disorganized speech) plus negative symptoms (flat affect, avolition) persisting beyond 6 months with a negative drug screen and no mood episodes confirm schizophrenia. Duration distinguishes it from schizophreniform disorder (1 to 6 months) and brief psychotic disorder (less than 1 month).
Full handout
High yield triage
Etiology / Epidemiology
Chronic thought disorder; equal sex incidence but earlier onset in men; positive symptoms tied to dopamine, negative symptoms to mesocortical dopamine hypoactivity.
Clinical Manifestations
Positive (delusions, hallucinations, disorganized speech) and negative (flat affect, avolition, social withdrawal) symptoms impairing function.
Diagnosis
Clinical, symptoms >6 months (vs schizophreniform 1-6 months, brief psychotic <1 month); rule out cocaine/amphetamine with urine drug screen.
Treatment
Atypical antipsychotics are first-line; clozapine for treatment-resistant disease (monitor CBC for agranulocytosis).
Prognosis
Roughly thirds: normal life, functional but symptomatic, or chronically hospitalized.
Full handout
Epidemiology & Etiology
Schizophrenia is a chronic thought disorder impairing judgment, behavior, and reality testing, with equal incidence in men and women but earlier onset in men (late teens-20s vs late 20s-30s). It is highly heritable. Neurochemically, positive symptoms relate to mesolimbic dopamine excess and negative/cognitive symptoms to mesocortical dopamine hypoactivity. A urine drug screen is essential to exclude cocaine or amphetamine-induced psychosis, and other medical causes of psychosis must be considered before diagnosis.
Pertinent Anatomy
The dopamine hypothesis localizes positive symptoms to a hyperactive mesolimbic dopamine pathway and negative/cognitive symptoms to a hypoactive mesocortical (prefrontal) pathway. Structural imaging shows lateral and third ventricular enlargement with decreased cortical volume; PET demonstrates hypoactive frontal lobes and hyperactive basal ganglia. Antipsychotic blockade of nigrostriatal D2 receptors produces extrapyramidal side effects, and tuberoinfundibular blockade causes hyperprolactinemia.
Pathophysiology
Schizophrenia is driven by dysregulated dopaminergic signaling, mesolimbic hyperactivity generating hallucinations and delusions, mesocortical hypoactivity generating negative and cognitive symptoms, with contributing glutamatergic (NMDA hypofunction) and cholinergic abnormalities. Neurodevelopmental insults produce the structural changes (ventricular enlargement, reduced cortical/hippocampal volume). The efficacy of D2-blocking antipsychotics and the psychotogenic effect of dopaminergic stimulants (cocaine, amphetamine) support the central role of dopamine.
Clinical Manifestations
The illness combines positive symptoms (delusions, hallucinations, classically auditory, disorganized speech, grossly disorganized or catatonic behavior) with negative symptoms (flat affect, alogia, avolition, poor grooming, social withdrawal) that severely impair functioning. By definition the disturbance persists for at least 6 months. Spectrum disorders differ chiefly by duration and content: brief psychotic disorder (>1 day to <1 month, often post-stressor), schizophreniform disorder (1-6 months), and delusional disorder (>=1 month of non-bizarre delusions with otherwise preserved functioning).
Diagnosis
Diagnosis is clinical and duration-based: schizophrenia requires characteristic symptoms for more than 6 months, schizophreniform for 1 to 6 months, and brief psychotic disorder for more than 1 day but less than 1 month, if no timeframe is given, schizophrenia is the default. Always obtain a urine drug screen to exclude cocaine/amphetamine-induced psychosis and rule out other organic causes. Schizoaffective disorder requires >=2 weeks of psychosis without mood symptoms during an illness with prominent mood episodes; mood disorder with psychotic features has psychosis only during mood episodes.
Treatment
Hospitalize acutely psychotic patients to ensure safety, then start an atypical antipsychotic as first-line (risperidone, olanzapine, quetiapine, aripiprazole, etc.). Match the agent to the patient: avoid olanzapine in obese/diabetic patients (weight gain, metabolic syndrome), use aripiprazole/ziprasidone when metabolic risk is high but avoid ziprasidone with QT prolongation, and favor long-acting injectables for nonadherence. Clozapine is the most effective drug for treatment-resistant schizophrenia (after >=2 failed trials) but requires regular CBC monitoring for agranulocytosis. Watch for extrapyramidal effects: acute dystonia (treat with benztropine/diphenhydramine), akathisia, tardive dyskinesia, and neuroleptic malignant syndrome (treat with dantrolene or bromocriptine).
Prognosis
Outcome divides roughly into thirds: one-third lead relatively normal lives, one-third remain symptomatic but functional, and one-third require frequent or long-term hospitalization. Good prognostic features include later onset, acute/rapid presentation, predominant positive symptoms, an identifiable mood component or precipitant, absence of family history, and lack of structural brain abnormalities. Early treatment and adherence improve long-term functioning; suicide risk is elevated.
Differential Diagnosis
Schizophreniform Disorder: identical symptoms lasting 1 to 6 months; becomes schizophrenia if persisting beyond 6 months.
Brief Psychotic Disorder: psychosis lasting more than 1 day but less than 1 month, often following a major stressor, with return to baseline.
Schizoaffective Disorder: psychotic symptoms present for >=2 weeks without mood symptoms, but mood episodes occur for the majority of the illness.
Substance-induced Psychosis: cocaine or amphetamine intoxication causes psychosis that resolves with abstinence; positive urine drug screen.
Delusional Disorder: isolated non-bizarre delusions for >=1 month with otherwise preserved functioning and no prominent hallucinations or negative symptoms.