History, aetiology, and symptomatology of schizophrenia

Schizophrenia is a severe, chronic, often disabling mental illness with onset characteristically in early adulthood. This article reviews the historical concepts of schizophrenia by Kraepelin and Bleuler, and discusses recent developments in the aetiology of schizophrenia, with an emphasis on the interplay between biological, psychological, and social factors. Genetic factors play an important role in the aetiology, as they ‘programme’ the early development of the brain’s structure, including the neurotransmitter receptor systems. According to the stress–vulnerability model, environmental stress and high ‘expressed emotion’ can precipitate the onset as well as influence the course and outcome of the illness. Cannabis abuse has a significant impact on the risk of schizophrenia, particularly in individuals with biological vulnerability to develop the illness. Clinically, patients with schizophrenia present with symptoms comprising positive (first-rank) and negative symptoms.