Most pharmacologic treatments of depression rely on serotonergic and/or noradrenergic mechanisms. Yet, evidence both from animal studies and from human trials suggests a role for dopaminergic pathways and particularly for dopamine D2-like receptors in the treatment of depression. In recent years, two new selective agonists of dopamine D2-like receptors have come into clinical use for the treatment of parkinsonism. Preliminary evidence suggests that these drugs might be useful as antidepressants. We are testing whether one of these agonists, ropinirole, is an effective augmentation strategy in depressed patients in a double-blind, randomized, controlled trial. We are recruiting unipolar and bipolar patients who remained depressed (modified Hamilton Depression Rating Scale score greater than 16) despite at least 4 weeks of treatment with an adequate dose of antidepressant medication. Patients receive either 2mg of oral ropinirole or placebo twice daily added on to their current medication and are evaluated weekly over 7 weeks and are assessed weekly using two depression rating scales.
