Pathophysiology

1) group of disorders marked by disturbances in thought patterns, speech, behavior, and perception 2) subtypes – paranoid, disorganized, catatonic, and residual 3) cause is unknown, but major risk factors are genetic susceptibility, early developmental insults, in utero viral influenza exposure, and winter birth (possibly related to influenza exposure)

Signs and Symptoms

Positive symptoms – 1) disorganized thought 2) delusions 3) hallucinations Negative symptoms – 4) social withdrawal 5) loss of functioning 6) flat affect 7) anhedonia

Histology/Gross Pathology

1) enlarged third and lateral ventricles 2) cortical atrophy 3) decreased size of hippocampus, amygdala, right prefrontal cortex

Associated Conditions

1) birth complications 2) Rh factor incompatibility 3) prenatal nutritional deficiency

Biochemistry

1) neuroleptics work on basis of diminishing dopaminergic activity 2) these drugs induce expression of c-fos gene in nucleus accumbens (dopaminergic connection between prefrontal and limbic cortices)

Inheritance/Epidemiology

1) onset classically in late adolescence or early adulthood 2) negative symptoms have a worse prognosis than positive symptoms 3) 300,000 new cases in USA each year 4) 50% concordance rate for monozygotic twins

Treatment

1) drugs – clozapine (blocks 5HT2 receptors), risperidone, haloperidol, chlorpromazine 2) behavioral and family education

Tips for USMLE

if 18 year-old college freshman has a history of appearing disheveled and having angry outbursts in class over a 3-month period and when summoned to the dean’s office about his behavior appears with a dead cat draped over his neck and shoulders, think schizophrenia