Thanks Hv, I have had my seratonin levels checked out, and I have normal to high seratonin levels each time I'm tested. So for me at least, this does not seem to be a problem. GABA is really expensive here, but I am going to try the ashwagandha.
Keep in mind that blood serotonin levels and brain serotonin levels are two separate things. Excessive serotonin in the brain can be a problem. So the serotonin produced by the flora (80% of the body's serotonin) does not cross in to the brain. The brain generates its own serotonin.