New study finds that add-on therapy improves depressive symptoms in bipolar disorder

Lingering depression is a serious and common problem in bipolar disorder, and does not resolve well with existing treatments. Because individuals with both depression and bipolar disorder experience a glutathione deficiency, an antioxidant that protects cells from toxins, researchers in a new study scheduled for publication in the September 15th issue of Biological Psychiatry sought to evaluate whether N-acetyl cysteine (NAC), an over-the-counter supplement that increases brain glutathione, might help alleviate depressive symptoms. Dr. Michael Berk and colleagues, in a randomized, double-blind, placebo-controlled trial, evaluated the mood symptoms of individuals with bipolar disorder, half of whom received placebo and half of whom received NAC, as an add-on therapy to their usual treatment. Over the 24 weeks of the study, NAC was well tolerated, and induced a marked and significant improvement in depressive symptoms. Ashley Bush, M.D., Ph.D., the article's corresponding author, further explains: "Glutathione is the brain's primary antioxidant defense, and there is evidence of increased oxidative stress in bipolar disorder. Therefore, we studied the potential benefit of NAC treatment in bipolar disorder and found that it impressively remedied residual depressive symptoms."

John H. Krystal, M.D., Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System, comments: "The preliminary evidence of efficacy of NAC is very interesting. This study might suggest a number of novel approaches to treating depression. In subsequent efforts to replicate this preliminary finding, it will be important to determine how much NAC reaches the brain after oral administration." As noted by both the authors and Dr. Krystal, additional studies will be necessary to further evaluate and replicate these findings. However, as Dr. Berk observes, "Brain glutathione metabolism appears to be a valuable new treatment target for psychiatric disorders, and we hope the impressive results of this study opens up a new treatment option."

Source: Elsevier