Evidence both from animal and human studies suggests a role for dopaminergic pathways in the treatment of depression. Ropinirole, a selective agonist of dopamine D2/D3, is in use for the treatment of parkinsonism. Preliminary evidence suggests that such agonists might be useful as antidepressants. We tested whether an add-on ropinirole is an effective in depressed patients.We conducted a double-blind, randomized, placebo-controlled trial of add-on ropinirole in depressed patients unresponsive to at least one antidepressant. We recruited 32 unipolar and bipolar patients who remained depressed (modified 21-item Hamilton Depression Rating Scale) despite at least 4 weeks of treatment with an adequate dose of antidepressant medication. Patients received either 2 mg of oral ropinirole or placebo twice daily added on to their current medication and were evaluated weekly for 7 weeks using the Hamilton Depression Rating Scale and Montgomery-Asberg Depression Rating Scale.No difference in primary or secondary outcome measures was detected between the treatment and control groups.These results differ from previous studies and are unexpected in light of theoretical considerations. This may indicate that there are differences in pharmacological activity between ropinirole and other dopaminergic agents such as pramipexole.
