The role of limbic and cortical regions in schizophrenia: focus on dopamine.

Dopamine is implicated in the pathogenesis of both the positive and the negative symptoms of schizophrenia. Clinical efficacy of antipsychotic drugs, without the production of side-effects, may be achieved by a dose-response separation of pharmacological function, regional (i.e., anatomical) selectivity of action, or by the selective targeting of neuroreceptors. The atypical antipsychotics have many different ways of acting on receptors in the brain, but they have in common a decreased likelihood of producing extrapyramidal side-effects. Patients respond well to them by showing improvements of both positive and negative symptoms. The preclinical profile of amisulpride shows specificity for D2/D3 dopamine receptors and selective activity in the limbic system. There is evidence that amisulpride is effective in treating both the negative and positive symptoms of schizophrenia, and that it has a low propensity to induce motor side-effects. Therefore, both positive and negative symptoms can be treated, without inducing these side-effects, by selectively targeting dopamine receptors.