The F.D.A. has been spiking wheat flour with niacin (vitamin B3) since 1938 to end the epidemic of the fatal B3-deficit disease pellagra. Pellagra carries psychosis, food aversion & insomnia as clinical symptoms. I suspect, but I can't prove, that the program (to vitalize the flour with niacin) has been curtailed, given that depression is epidemical here.