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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.

Background: Dysthymia is a common mental disorder, associated with considerable disability and high co-morbidity. This review assessed the role of pharmacological treatment., Methods: All randomized-controlled trials that compared active drug versus placebo for dysthymic patients were included. Pooled relative risks (RR) and 95% confidence intervals (CI) were calculated with the Random Effect Model method. Where possible, number needed to treat and number needed to harm were estimated., Results: Fifteen trials were included for the main comparisons. Similar results were obtained in terms of efficacy for different groups of drugs, such as tricyclic (TCA), selective serotonin reuptake inhibitors (SSRI), monoamine oxidase inhibitors (MAOI) and other drugs (sulpiride, amineptine, and ritanserin). The pooled RR treatment response was 0.68 (95% CI 0.59-0.78) for TCA, 0.64 (95% CI 0.55-0.74) for SSRIs, 0.59 (95% CI 0.48-0.71) for MAOIs. Other drugs (amisulpride, amineptine and ritanserin) showed similar results. Patients treated on TCA were more likely to report adverse events, compared with placebo. There were no differences in response to active treatment when dysthymia was compared to either dysthymia plus major depression or briefer non-major depressive states., Conclusions: Drug treatment appears to be effective in the short-term management of dysthymic disorder. The choice of drug should take into account specific side-effects profile of each drug.

Antipsychotic drugs are effective in psychoses, whatever the etiology of the disorder. The positive symptoms tend to respond more readily. The need for developing new drugs arises from the refractoriness of the negative symptoms, the 10-25% of the patients that are treatment-resistant and the problems of short-, and long-term extrapyramidal side-effects. Thus far, six drugs, differing from the classical antipsychotics, have been licensedfor use: olanzepine, risperidone and quetiapine; the longest registration exists for sulpiride and clozapine while the most recent one is for amisulpride. This review starts with a brief introduction to symptomatology, and takes differences with the classical drugs in pharmacology, pharmacokinetics, clinical aspects and side-effects into consideration. Clozapine, risperidone and sulpiride may be considered for clinical use in refractory patients; these three, olanzapine and amisulpride when extrapyramidal side-effects cause a clinical problem. Amisulpride and sulpiride have a dual therapeutic acion: On negative symptoms at low dose, on positive symptomen at high doses.