Toxoplasma gondii Seropositivity and Suicide Rates in Women
In conclusion, the results suggest that a positive relationship between rates of infection with T. gondii and suicide is apparent in women of postmenopausal age. Prospective studies are necessary to further confirm this association predictively and to explore mechanisms mediating this relationship.
and brain cancer -
Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common.
Infection with T. gondii was associated with a 1.8-fold increase in the risk of brain cancers across the range of T. gondii prevalence in our dataset (4–67%). These results, though correlational, suggest that T. gondii should be investigated further as a possible oncogenic pathogen of humans.
Both these papers are from 2011. It's pretty clear there's something going on even if we don't know exactly what it is.