S-adenosyl-methionine improves depression in patients with Parkinson's disease in an open-label clinical trial

We report a pilot study of S-adenosyl-methionine (SAM) in 13 depressed pati ents with Parkinson's disease. All patients had been previously treated wit h other antidepressant agents and had no significant benefit or had intoler able side effects. SAM was administered in doses of 800 to 3600 mg per day for a period of 10 weeks. Eleven patients completed the study, and 10 had a t least a 50% improvement on the 17-point Hamilton Depression Scale (HDS). One patient did not improve. Two patients prematurely terminated participat ion in the study because of increased anxiety. One patient experienced mild nausea, and another two patients developed mild diarrhea, which resolved s pontaneously. The mean HDS score before treatment was 27.09 +/- 6.04 (mean +/- standard deviation) and was 9.55 +/- 7.29 after SAM treatment (p <0.000 1). Although uncontrolled and preliminary, this study suggests that SAM is well tolerated and may be a safe and effective alternative to the antidepre ssant agents currently used in patients with Parkinson's disease.