schizoaffective disorder

**DSM-5 diagnostic criteria (high-yield):** - An uninterrupted period of illness with a major mood episode (major depressive or manic) concurrent with Criterion A of schizophrenia (≥2 of: delusions, hallucinations, disorganized speech, grossly disorganized/catatonic behavior, negative symptoms). - Delusions or hallucinations for ≥2 weeks WITHOUT a major mood episode at some point in the lifetime illness (this separates it from mood disorder with psychotic features). - Mood episode symptoms are present for the MAJORITY of the total duration of the active and residual illness. - Not attributable to a substance or another medical condition.

**Subtypes:** - Bipolar type: manic episodes present (with or without major depressive episodes). - Depressive type: only major depressive episodes.

**Differential (classic exam discriminators):** - Schizophrenia: mood episodes are brief relative to the total duration of the psychotic illness. - Mood disorder with psychotic features: psychosis occurs ONLY during mood episodes. - Schizoaffective: psychosis ≥2 weeks WITHOUT mood symptoms, and mood symptoms are present most of the illness. - Also exclude substance-induced psychosis, medical causes (e.g., temporal lobe epilepsy, SLE, steroids, thyroid disease), and schizophreniform disorder (<6 months).

**Epidemiology/pathophysiology:** - Lifetime prevalence is about 0.3%, which is lower than schizophrenia. Onset is typically early adulthood. The bipolar type is more common in younger patients and the depressive type in older adults. Women are more often affected than men, mainly with the depressive type. - Etiology is multifactorial: shared genetic liability with schizophrenia and bipolar disorder (family history of either raises risk). Proposed mechanisms include dopamine dysregulation (mesolimbic hyperactivity causing positive symptoms), glutamate (NMDA hypofunction), and serotonin/other monoamine involvement.

**Management:** - Antipsychotics are the mainstay (second-generation preferred). Paliperidone is the only FDA-approved medication for schizoaffective disorder (monotherapy or adjunct to mood stabilizers/antidepressants). - Bipolar type: antipsychotic plus a mood stabilizer (lithium, valproate). - Depressive type: antipsychotic plus an antidepressant (SSRI). - Clozapine is used for treatment resistance or persistent suicidality. Long-acting injectables improve adherence. Psychosocial interventions include CBT, social skills training, supported employment, and family psychoeducation. ECT is an option for refractory cases or catatonia. - Monitor for metabolic syndrome with SGAs, and monitor lithium levels, renal and thyroid function.

**Prognosis:** - Intermediate between schizophrenia (worse) and mood disorders (better). The suicide risk is substantial (about 5–10% lifetime), especially in the depressive type. Comorbid substance use is common.

**Buzzwords:** Psychosis ≥2 weeks without mood symptoms + prominent mood episodes for most of the illness → schizoaffective. Paliperidone = FDA-approved.