[Psychopathological correlates of dopaminergic dysfunction in alcoholic and schizophrenic patients]

Abstract

It has been suggested that anhedonia, the loss of pleasure, is associated with a dysfunction of the dopaminergic reward system in schizophrenic and alcohol-dependent patients. In a series of neuroendocrinological and brain imaging studies, we examined pre- and postsynaptic mechanisms of dopaminergic neurotransmission in non-human primates and in schizophrenic and alcohol-dependent patients. Among alcoholics, we found indicators of a sensitization of dopaminergic neurotransmission, which was associated with the relapse risk, but not with anhedonia or depression. Schizophrenics with neuroleptic blockade of striatal dopamine D2 receptors displayed psychomotor slowing and reduced motivation, but not anhedonia. Primate studies pointed to the importance of a temporocortical dysfunction in the pathogenesis of phasic dopaminergic dysregulation in the striatum. These observations indicate that a dysfunction of stimulus-dependent dopamine release may be associated with motivational deficits caused by a reduction in incentive salience, but not with anhedonia.