Chapter 58 - The Neurochemistry of Schizophrenia

Abstract

Publisher Summary This chapter reviews the compelling evidence that schizophrenia is a brain disease with a high degree of heri­tability. The conceptualization of schizophrenia as a specific dis­ease occurred at the turn of the last century. The schizophrenia disease has its age of symptomatic onset in late adolescence and early adult­hood in males and somewhat later in females, who tend to be less severely affected. Since schizophrenia starts in young adulthood and is known as a lifelong disorder, it produces a substantial degree of persistent disability. Schizophrenia does not follow a Mendelian inheritance pattern and cannot be attributed to a single gene or genetic abnormality. The pattern of distribution of schizophrenia within affected families, with a rapid tailing off of concor­dance in identical twins (approximately 60%) versus fraternal twins and first-degree relatives (10%) versus second-degree relatives (3%), is consistent with complex genetics, in which many genes of small effect interact to contribute to the phe­notype. Retrospective and prospective studies of children, who are at genetic high risk for schizophrenia, indicate that subtle abnor­malities in cognitive function and attention, social oddness and motor clumsiness are often present years before the onset of psychosis. The variation in symptomatic features of schizophrenia across individuals and the common nature of the disorder strongly suggest that there can be multiple causes that result in the phenotype.