In the largest clinical trial to date, pramipexole was found to be substantially more effective than a placebo at reducing the symptoms of treatment resistant depression (TRD) over the course of nearly a year, when added to ongoing antidepressant medication.
The trial, supported by National Institute for Health and Care Research (NIHR) and published in The Lancet Psychiatry, included 150 patients with treatment resistant depression, with equal numbers receiving 48 weeks of pramipexole or a placebo, alongside ongoing antidepressant medication.
Overall, the group taking pramipexole experienced a significant and substantial reduction in symptoms by week twelve of treatment, with the benefits persisting over the course of a year. However, there were also significant side effects, such as nausea, sleep disturbance and dizziness, with around one in five people on pramipexole dropping out of the trial as a result.
Professor Michael Browning, from the Department of Psychiatry, University of Oxford, and workstream lead in Mood Disorders for the NIHR Mental Health-Translational Research Collaboration (MH-TRC) Mission, who led the trial, said: 'Effectively treating people who have not responded to first-line interventions for depression is a pressing clinical problem and there has long been an urgent need to find new treatments.