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Schizophrenia is a persistent and severe psychiatric condition characterized by neurocognitive decline and impairment in reality testing.
- Major psychiatric disorder characterized by prodrome, active, and residual psychotic symptoms involving disturbances in appearance, speech, behavior, perception, and thought that last for at least 6 months
- DSM-5 eliminated subcategories of schizophrenia (1).
- System(s) affected: central nervous system (CNS)
- 7.7 to 43/100,000
- Predominant sex: male-to-female ratio = 1.4:1.0
- Age of onset: typically <30 years, earlier in males (early to mid-20s) than females (late 20s), with a smaller peak that occurs in women >45 years
- Lifetime (1%): highest prevalence in lower socioeconomic classes and urban settings (2-fold higher risk)
- 1.1% of the population >18 years old; similar rates in all countries
Etiology and Pathophysiology
- Stems from a complex interaction between genetic and environmental factors; higher incidence if prenatal infection or hypoxia, winter births, first-generation immigrants, advanced paternal age, drug use, and genetic (velocardiofacial) syndromes
- Overstimulation of mesolimbic dopamine D2 receptors, deficient prefrontal dopamine, and aberrant prefrontal glutamate (NMDA) activity results in perceptual disturbances, disordered thought process, and cognitive impairments
If first-degree biologic relative has schizophrenia, risk is 8–10% (a 10-fold increase).
- Currently, no known preventive measures decrease the incidence of schizophrenia.
- Interventions to improve long-term outcome and associated comorbid conditions are employed during management.
Commonly Associated Conditions
- Nicotine dependence (>50%) (1) and substance use disorders are common and lead to significant long-term medical and social complications.
- Metabolic syndrome, diabetes mellitus, obesity, and certain infectious diseases, including HIV, hepatitis B, and hepatitis C all occur in higher-than-expected rates in individuals with schizophrenia.