Schizophrenia

Schizophrenia is a chronic, severe mental disorder characterized by distortions in thinking, perception, emotions, language, sense of self, and behavior, often including hallucinations, delusions, and disorganized thinking.

Definition

Epidemiology

Affects approximately 1% of the global population
Onset typically in late adolescence to early adulthood
Slightly earlier onset in males (late teens to early 20s) than females (20s to early 30s)
Chronic course with periods of remission and relapse
High burden of disability and reduced life expectancy, often due to comorbid conditions or suicide

Etiology

Genetic predisposition: strong familial aggregation and polygenic risk factors
Neurodevelopmental abnormalities during fetal or early life
Environmental factors: prenatal infections, obstetric complications, urban upbringing, childhood trauma
Neurochemical imbalances: dopaminergic hyperactivity, glutamate dysfunction
Structural and functional brain abnormalities: enlarged ventricles, reduced gray matter
Interaction of genetic and environmental factors

Pathophysiology

Dysregulation of dopaminergic pathways leading to positive symptoms
Glutamatergic hypofunction contributing to cognitive and negative symptoms
Structural brain changes: cortical thinning, hippocampal volume loss
Altered connectivity in frontotemporal and limbic circuits
Neuroinflammation and oxidative stress in chronic cases
Abnormal synaptic pruning during adolescence
Combination of genetic vulnerability and environmental insults influencing disease expression