Genotype-Dependent Adaptation of Brain Dopamine System to Stress

Stress is considered to play a basic role in the etiology of some psychotic syndromes either as primary cause or as a precipitating factor. In both cases the individual genetic make-up is believed to be crucial in mediating the pathological effects of stress (Snyder et al., 1974; Crow, 1979; Stevens, 1979; Ciaranaello and Boheme, 1982). Twin studies on the genetic basis of schizophrenia give concordance rate for this disorder of less than 100% in monozygotic twins, thus indicating a role of environmental factors (Kety, 1982; Diedern, 1983). Disturbed behavior is therefore considered to result from the interaction between environmental pressure (stress) and genetically susceptible individuals (Hirsh, 1979; Gottesman and Shield, 1982). According to this view a psychotic outcome will result from genotype-dependent responses of the organism to stressful experiences, thus not only from environmental pressure or genotype, but, also, from the interaction between genotype and stress.