Description

A disorder where thoughts and emotions are disrupted; seen in schizophrenia, mood disorders, substance use, medical problems, delirium, and dementia;

• Positive symptoms: hallucinations and delusions (fixed false beliefs not typical of cultural background)
• Negative symptoms: anhedonia, poverty of speech, lack of motivation, social withdrawal, affective blunting
• Cognition: poor working memory, information processing, inattention, disorganized speech and/or behavior

Epidemiology

Prevalence

• Schizophrenia: peak onset: males: 18 to 25 years old; females: 25 to 35 years old
• 1% of the U.S. population; similar percentage worldwide
• Seen in ~50% of bipolar cases and 20% of unipolar depression cases

Etiology and Pathophysiology

• Many causes including psychiatric, medical, and/or substance use
• Positive symptoms: excessive dopaminergic activity in the mesolimbic pathway
• Negative symptoms: diminished dopaminergic activity in mesocortical pathway

Genetics
Schizophrenia: 50% concordance in monozygotic twins; many genes involved

Risk Factors

Substance use (particularly stimulants and THC), family history of psychosis, lower socioeconomic status

General Prevention

Community interventions for early detection and treatment of prodromal symptoms.

Commonly Associated Conditions

• Associated with metabolic syndrome, autonomic dysfunction, sudden cardiac death, and breast and lung cancer
• Substance use, including nicotine dependence