ABSTRACT
BIOCHEMICAL ALTERATIONS IN SCHIZOPHRENIA Most candidate genes for schizophrenia are either directly or indirectly related to neural plasticity, synaptogenesis, or transmitter function within brain circuits that are involved in information processing (for review, see 1, 2). In accordance, multiple neurotransmitters have been implicated in the disturbances in early information processing and higher cognitive functions that are believed to constitute core features in schizophrenia. These disturbances are primarily genetically determined and considered to be important markers for the disease (see Chapter 2.6). They are also believed to predispose for development of positive and/or negative schizophrenic symptoms (3-6) and are, therefore, central for most (neurochemical) hypotheses for schizophrenia. Given the heterogenic character of the disease, different transmitter systems within different brain loops are likely to be involved in different patients. In addition, it is important to keep in mind that the disturbances observed in the patients might be secondary adaptive changes to primary dysfunctions. Nevertheless, an abundant literature has demonstrated transmitter disturbances in patients with schizophrenia, and pharmacological treatment is the cornerstone for all other interventions in this disease. In the following, we will describe the systems that most constantly have been found altered in schizophrenia (Table 11.1).
