Mechanism of Action of Neuroleptics in the Treatment of Schizophrenia Although atypical antipsychotics are becoming the treatment of choice for schizophrenia, what makes the antipsychotic „atypical“, is not clear [3]. New Findings based on research using positron emission tomography (PET) were published recently. Schizophrenic patients have increased synaptic dopamine concentrations in the striatum; antipsychotics with high affi nity for dopamine D(2) receptors are associated with a substantial increase in D(2) receptor binding; Columbia study provides an important indication of hyperdopaminergic function in schizophrenia; antipsychotic effi cacy of atypical antipsychotics has been observed at lower D(2) receptor occupancy rates than with typical neuroleptics. Based on this and other new fi ndings the Schizophrenia research group in Toronto propose than fast dissociation from the D(2) receptor makes an antipsychotic more accomodating of physiological dopamine transmision, permitting an antipsychotic effect without motor side effects. In contrast to the multireceptor hypotheses, the authors predict that the atypical antipsychotic effect can be produced by appropriate modulation of the D(2) receptor alone; the blockade of other receptors is neither necessary nor suffi cient.

        Key words: schizophrenia, dopamine hypothesis, D(2) receptors, fast dissociation from the D(2) receptor.