Food / eating.
My food sensitivities are basically mini POIS episodes. It's taken me years to actually consciously realise this. For some reason, an animal-based diet seems to provide the best relief diet-wise. The symptoms are anxiety, brainfog, anhedonia, social anhedonia, cognitive/decision-making symptoms and a general weakness. They appear very quickly after eating, which is something I always found interesting when comparing it to other non-POIS accounts of food sensitivities which could occur many hours or days later.