Is this the study?
Bacopa monniera Wettst. (syn. Herpestis monniera L.; Scrophulariaceae) is a commonly used Ayurvedic drug for mental disorders. The standardized extract was reported earlier to have significant anti-oxidant effect, anxiolytic activity and improve memory retention in Alzheimer's disease. Presently, the standardized methanolic extract of Bacopa monniera (bacoside A - 38.0+/-0.9) was investigated for potential antidepressant activity in rodent models of depression. The effect was compared with the standard antidepressant drug imipramine (15 mg/kg, ip). The extract when given in the dose of 20 and 40 mg/kg, orally once daily for 5 days was found to have significant antidepressant activity in forced swim and learned helplessness models of depression and was comparable to that of imipramine.
http://www.ncbi.nlm.nih.gov/pubmed/12046860
It was only given for 5 days and most antidepressants take a few weeks to start working. In any case, this is very interesting. I actually wanted to take bacopa, but I read that it can decrease motivation and increase apathy. Have you noticed any changes in motivation or apathy?
Interesting note about random memories coming to mind. I've experienced this effect while on Wellbutrin, Rhodiola Rosea, and Moclobemide. Though, recently Rhodiola hasn't been working the same as it did last year. I think NOW Foods changed their supplier as the new pills are bigger and have a cloudy yellow hue to them, whereas the older pills were smaller and dark red. Anyway, the random memories were mostly from my childhood and a lot of them were nostalgic. 5-HT1A may be involved in this as all three substances affect it in one way or another. Wellbutrin desensitizes the autoreceptor, Rhodiola increases the 5-HT1A receptor count, and Moclobemide increases serotonin so it should increase 5-HT1A receptor activity.
It seems bacopa agonizes the 5-HT1A receptor and affects the 5-HT2A receptor in some way:
Researchers at the University of Montana have released results from a recent in vitro study on a standardized extract of Bacopa monnieri, a plant used widely and historically in the traditional Indian system of Ayurveda to enhance cognitive health, memory and mood. The results were presented at a poster session at the annual meeting of the American Society of Pharmacognosy held at Oregon State University in Corvallis, OR, in July. While previous in vitro studies on Bacopa focus on the neurotransmitters GABA and acetylcholine, this study provided direct evidence that Bacopa can also regulate the activity of specific serotonin receptors. The study concluded that the Bacopa extract displaces antagonist [3H] Ketanserin from serotonin receptor 5HT2a isolated from rats, and exhibited even stronger effects in its displacement of agonist 8-OH-DPAT from the 5HT1a receptor. The study also concluded that this Bacopa extract decreases cAMP production in cells with 5HT1a receptors, suggesting it causes an agonistic effect. This effect was similar to results from a previous study where Bacopa displayed antidepressant effects comparable to imipramine. Geni Herbs manufactured the Bacopa extract used in the study.
http://www.thefreelibrary.com/Bacopa+extract+displays+strong+serotonin+receptor+activity.-a0139683595
Yeah, I'm also wondering how people in the past discovered the uses of such herbs as bacopa. Like you said, it can cause diarrhea, but not everyone will experience it. Someone must have only experienced positives after taking it and spread the word.
