The dopamine agonist apomorphine differentially affects cognitive performance in alcohol dependent patients and healthy controls

Abstract

BACKGROUND: Reduced metabolic activity in frontal brain regions, and reduced striatal dopamine receptor densities have been shown in alcohol dependent patients. Little is known on functional changes in the fronto-striatal-thalamic dopaminergic neurocircuitry in these patients. The objective of this study was to assess sensitivity of prefrontal dopamine receptors in alcohol dependent patients. EXPERIMENTAL PROCEDURES: Male alcohol dependent patients (N=40) and healthy controls (N=39) performed an AX-continuous performance test before and after administration of the DA agonist apomorphine (0.005 mg/kg). RESULTS: At baseline alcohol dependent patients were slower and less accurate compared to healthy controls. After administration of apomorphine, performance improved in alcohol dependent patients and deteriorated in healthy controls. CONCLUSIONS: Reduced cognitive performance in alcohol dependent patients compared with healthy controls may indicate dopamine dysfunctioning at the prefrontal level. Improvement of cognitive performance in alcohol dependent patients after administration of apomorphine and deterioration in healthy controls provides evidence for an inverted U-shape relation between dopaminergic functioning and cognitive performance.