Although it’s too early to say that yeast infections cause mental problems, there does appear to be an association that could point to immune system weakness, bad lifestyle choices and gut-brain connections, say researchers from John Hopkins University school of medicine.

In one test, 26 per cent of men with bipolar disorder had a history of Candida infection, compared to a 14 per cent infection rate among healthy males. Interestingly, a similar association wasn’t seen in women.

Candida is a yeast-like fungus that is in all human digestive tracts, but its overgrowth can cause burning and itching. In serious cases, it can enter the bloodstream.

It can be treated in its earliest stages by limiting sugar in the diet, making other dietary changes, avoiding antibiotics and improving hygiene, say the researchers.