Schizophrenia

Schizophrenia is a disabling psychiatric condition impacting around 1% of people worldwide and ranking among the top 10 global disability causes. Schizophrenia is characterized by positive psychotic symptoms such as hallucinations, delusions, disorganized speech, and disorganized or catatonic behavior; negative symptoms such as reduced motivation and expressiveness; and cognitive impairments affecting executive function, memory, and mental processing speed. The effect of schizophrenia on daily life varies greatly, with many individuals facing significant disability and incomplete recovery. Even those with more favorable outcomes confront challenges such as social isolation, stigma, and reduced opportunities for forming close relationships. Unemployment rates among people with schizophrenia are notably high. Factors such as poor diet, weight gain, smoking, and concurrent use of substances are prevalent, collectively shortening life expectancy by an estimated 13 to 15 years. The lifetime risk of death by suicide in patients with schizophrenia is 5% to 10%. Although current diagnostic and treatment approaches in schizophrenia primarily emphasize psychotic symptoms, the disorder's negative and cognitive symptoms play a significant role in impairing social and occupational functioning and often show limited response to antipsychotic medications. This perspective aligns with historical views on the condition: Emil Kraepelin initially described "dementia praecox," which Eugen Bleuler later renamed "schizophrenia." Notably, both Kraepelin and Bleuler did not regard delusions and hallucinations (positive) symptoms as the central characteristics of the illness, suggesting a need for a broader focus on understanding and managing schizophrenia. The clinical diagnosis of schizophrenia is made after obtaining a detailed psychiatric history and mental status examination and after ruling out other psychiatric and medical causes of psychosis. Risk factors include birthing complications, the season of birth, severe maternal malnutrition, maternal influenza during pregnancy, family history, childhood trauma, social isolation, cannabis use, minority ethnicity, and urbanization. The disorder's etiology and pathophysiological mechanisms remain elusive due to its complexity and heterogeneity. Despite its relatively low prevalence, schizophrenia significantly contributes to the global burden of disease. More than half of those diagnosed with schizophrenia have multiple comorbidities, both psychiatric and medical.