Abstract
Treating bipolar depression that comes with obsessive, looping thoughts can be tricky because standard antidepressants often help only a little and can sometimes push the mood too high. In this report, we followed a 32-year-old man whose low mood and health-related ruminations lingered despite mood stabilisers (valproate, low-dose aripiprazole, pregabalin, and Deanxit). Hoping to copy some of ketamine's brain-circuit effects, he tried an over-the-counter mix of dextromethorphan, piracetam, and L-glutamine; the result was modest at best. Ten days after he added 600 mg of the herbal CYP2D6 inhibitor goldenseal, thought to slow the breakdown of dextromethorphan, he reported a clear lift in energy, mood, and work performance, with no signs of hypomania; the improvement faded when he stopped the herb and returned when he restarted it, and he had no side effects. Although this single experience cannot show cause and effect, it hints that short courses of a well-standardised botanical CYP2D6 inhibitor might prolong the benefit some patients get from oral dextromethorphan-based combinations, an idea that would need careful study, including drug-level monitoring and checks for mood switches.