SAM-e Treatment of Depression in Parkinson's Disease.

PD is commonly associated with depression, but conventional antidepressants have limited efficacy in patients with PD and may exacerbate motor symptoms. SAM-e is available in the United States as a food supplement and is promoted as a mood enhancer. SAM-e improves dopamine transmission, may have a beneficial effect on dopamine receptors, and may be a good alternative to the currently-used antidepressants in patients with PD. This study will investigate whether SAM-e is safe and effective in the treatment of depression associated with PD. The efficacy of SAM-e will be compared to placebo and to escitalopram, a selective serotonin reuptake inhibitor commonly used for the treatment of depression in PD.

Participants in this study will be randomly assigned to receive SAM-e, escitalopram, or placebo for 12 weeks. Some participants may choose to extend treatment for an additional 12 weeks (for a total of 24 weeks on study medication). Participants will have study visits at entry and Weeks 2, 4, 8, and 12. Study visits will include neurological evaluation, psychiatric evaluation, blood tests, and quality of life questionnaires. A telephone interview will be conducted at Week 10.