Psych| Schizophrenia
5.09 Schizophrenia Psychiatry review for the USMLE Step 1 Exam Epidemiology: Slight male predilection (1.4:1 male to female ratio). Men present between 18-25, women between 28-35. Affects about 0.5% of the population. Symptoms: Positive symptoms: hallucinations, delusions, disorganized behavior and speech. Negative symptoms: flat affect, anhedonia, apathy, alogia, lack of interest in socialization. Cognitive symptoms: impairments in attention, executive function, working memory. Diagnosis: Criteria: two or more symptoms lasting over a month. Schizophreniform disorder if symptoms last less than 1 month. Pathophysiology: Excess dopamine in prefrontal cortical pathway (negative symptoms). Excess dopamine in mesolimbic pathway (positive symptoms). Other neurotransmitters may also play a role (especially serotonin excess). Treatments: Antipsychotics (D2 receptor antagonists). First-generation antipsychotics: haloperidol, chlorpromazine (more side effects). Second-generation antipsychotics (atypical antipsychotics): aripiprazole, olanzapine, quetiapine, risperidone (lower extrapyramidal side effects, higher metabolic side effects). Outcomes: Rule of thirds: one-third full recovery, one-third improved with mild symptoms, one-third require high-level care.