[Antidepressant effects of dopamine agonists. Experimental and clinical findings]

Results of preclinical and clinical studies implicate that, in addition to serotonin and norepinephrin, dopaminergic mechanisms play a role in the pathogenesis and treatment of depression. Newer antidepressants such as bupropion, sertraline, and venlafaxine act as partial inhibitors of presynaptic dopamine reuptake. Experimental studies show that dopaminergic effects contribute to the development of anxiety, depression, and anhedonia. These studies revealed, among the new nonergot dopamine agonists, anxiolytic properties for ropinirole and anxiolytic, antidepressive, and antianhedonic effects of pramipexole which seem to relate to its specific action on D(2) and D(3) receptors in the mesolimbic system and prefrontal cortex. In addition, affective disorders may be associated with impairments of neuronal plasticity, and pramipexole seems to exert neurotrophic properties. Controlled and open studies in depressed patients with Parkinson's disease show therapeutic effects of dopamine agonists on motor deficits, anhedonia, and depression. Various dopamine agonists have been tested in open studies in patients with depression and may add to the spectrum of treatment options in mood disorders. Recently published placebo-controlled trials in small patient groups implicate that pramipexole is effective as additional treatment to mood stabilizers in I and II bipolar depression.