Definition and Diagnosis
Schizophrenia is a chronic, severe psychotic disorder characterized by a combination of positive symptoms (hallucinations, delusions, disorganized speech or behavior), negative symptoms (diminished emotional expression, avolition), and cognitive impairment, causing significant social and occupational dysfunction.
Epidemiology
Schizophrenia affects approximately 0.3-0.7% of the population worldwide, with onset typically in late adolescence to the mid-thirties, and generally earlier in men than in women.
Risk Factors
Risk factors include a strong genetic component (heritability estimated around 80%), obstetric complications, prenatal infection or malnutrition, urban upbringing, migration, cannabis use during adolescence, and advanced paternal age.
Symptoms and Subtypes
Positive symptoms include hallucinations (commonly auditory) and delusions; negative symptoms include blunted affect, social withdrawal, and reduced motivation; disorganized speech and behavior and cognitive deficits in memory and executive function are also core features.
Diagnosis
DSM-5-TR requires two or more characteristic symptoms (at least one being delusions, hallucinations, or disorganized speech) present for a significant portion of one month, with continuous signs of disturbance persisting for at least six months and significant functional decline.
Treatment
Antipsychotic medication is the cornerstone of treatment, alongside psychosocial interventions such as CBT for psychosis, family psychoeducation, social skills training, and supported employment or education. Early intervention programs improve long-term outcomes.
Prognosis
Course is variable; roughly a third of individuals achieve good functional recovery, a third have an intermediate course with recurring episodes, and a third experience a more persistently disabling course, though outcomes have improved with early, sustained treatment.
Reference
Sadock, B. J., Sadock, V. A., & Ruiz, P. Kaplan & Sadock's Synopsis of Psychiatry (11th ed.); New Oxford Textbook of Psychiatry (2nd ed.).