OK, it does appear that the qigong psychotic raction is real, or at least real enough to be listed on a gov.uk site.
Question seems to be what might cause this. Operational theory seems to be going into the emptiness without coming back fully, so that you experience something akin to a hypogogic/hypnopopic state. The cure would seem to be going fully into the emptiness via a voluntary shut-down of the reticular formation vis-a-vis taking a nap. The natural, instinctive cycle would then move the qigong practioner from a state of complete unconsciousness to a state of full lucidity once the bodymind refreshes itself.
I would also search the archives of this forum if you believe this may become an issue for you. It may be that Spring Forest Qigong is designed in such a way that said psychosis will not occur. Given the length of time that went into this (20+ years) and the intensity of Master Lin's personal practice of qigong, there seems to be a good chance that Spring Forest Qigong is safe even when practiced in excess of six hours per day.
