Tryptophan and Turkey?

"The amino acid l-tryptophan, the pre-cursor to serotonin, was actually available over the counter in capsule form in health food stores up until the mid to late 80's (but a single bad batch produced in Japan in the late 80's caused a wide spread alarm?it was quickly taken off the market, hasn't returned, and probably won't any time soon.). Interestingly enough, around that same time, the new SSRI [selective serotonin reuptake inhibitor] anti-depressants were created and released for human consumption." By Robert Sigler.