Elsevier

The Lancet

Volume 353, Issue 9162, 24 April 1999, Pages 1425-1430
The Lancet

Seminar
Schizophrenia

https://doi.org/10.1016/S0140-6736(98)07549-7Get rights and content

Summary

Schizophrenia is among the most severe and debilitating of psychiatric disorders. Diagnosis is currently by criterion-based systems, including positive (eg, hallucinations and delusions) and negative (eg, avolition and alogia) symptoms. The importance of negative symptoms in the course and outcome of the illness is increasingly being studied. Current research seeks to detect causal mechanisms in schizophrenia through studies of neural connectivity and function, as well as models of genetic transmission, such as polygenic models of inheritance in genetic research. Potential genes have been identified that may confer vulnerability to the illness, perhaps in conjunction with environmental factors. Neuroimaging research with magnetic resonance imaging and positron emission tomography has investigated differences in volumes and functional dysregulation in specific neural subregions. Areas studied include the frontal and temporal cortex, the hippocampus, the thalamus, and the cerebellum. Despite these advances, treatment of symptoms and psychosocial and cognitive impairments remains only partially successful for many patients.

Section snippets

Diagnosis of schizophrenia

Schizophrenia is a complex medical disorder with diverse clinical presentations. Several cognitive and emotional functions are impaired, such as perception (hallucinations), inferential thinking (delusions), motivation (avolition), and thought and speech (alogia). Criterion-based systems have been developed to decrease the complexity and improve the reliability of diagnosis. These systems include the International Classification of Diseases, tenth edition (ICD-10)3 and the Diagnostic and

Genetic research in schizophrenia

Risk of schizophrenia is higher among family members of patients than in the general population. Adoption studies have shown that this increased risk is genetic, with a tenfold increase in risk associated with the presence of an affected first-degree family member. This genetic risk increases with each affected family member, to nearly 50% when both parents are affected.7 Inheritance of schizophrenia has largely been studied through mathematical modelling of pedigrees and twin and adoption

Neuroimaging of neural substrates

The neural substrates of schizophrenia have been intensively studied by traditional neuropathology techniques and neuroimaging. Postmortem studies of patients with schizophrenia have shown no increase in degenerative pathology such as that known to occur in Alzheimer's disease.14 The consistent absence of degenerative pathology (eg, gliosis) suggests that schizophrenia may result from pathological neurodevelopmental processes.

The use of magnetic resonance imaging (MRI) has permitted

Medication

Antipsychotic medications have for more than 45 years substantially lessened the morbidity associated with schizophrenia. Despite being the mainstay of treatment, standard antipsychotic medications have been associated with inadequate efficacy and substantial side-effects. Traditionally, antipsychotic medications were shown to be effective because of their ability to antagonise dopamine receptors. Non-selectivity of this antagonism led, however, to undesirable effects, such as extrapyramidal

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