A Denmark study from the July 2 issue of Archives of General Psychiatry found that women infected with the parasite Toxplasma gondii, spread from the faeces of infected kitties, had an increased risk of self-directed violence.
The study measured the levels of Toxoplasma-specific IgG antibodies of almost 46,000 mothers, and found that women with high levels of the antibodies had a significantly higher risk of developing schizophrenia spectrum disorders and attempting suicide.
More than 500 female participants in the study attempted suicide, which means that the overall actual risk of attempting to take your own life was still small.
The T. gondii parasite is extremely common, with about one-third of the world's population thought to be infected. The parasite is hard to detect as most people don't show symptoms and the parasite itself hides from the immune system in cysts throughout the brain and muscles.
While cats, both wild and domestic, are the definitive hosts of T. gondii, humans can also contract the parasite from eating raw or undercooked meat containing the parasite. The parasite is dangerous to people with lowered immune systems and pregnant women.
The mind-altering effects of the T. gondii parasite don't end there. A 2006 study by infectious disease researcher for the Sydney University of Technology, Dr Nicky Boulter, revealed that affected men had lower IQs and shorter attention spans, while affected women were more outgoing, promiscuous and were considered more attractive to men.