The Toxoplasma Gondii parasite commonly associated with cats is linked to generalized anxiety disorder and autism.
The Toxoplasma gondii’s eggs are present in cat feces, and one of the most common ways people are infected with Toxoplasma gondii is through contact with an infected cat.
A study published in the journal Brain, Behavior, and Immunity found that 500 participants with anxiety disorders had a past Toxoplasma gondii infection. In addition, the researchers found that a past Toxoplasma gondii infection was linked to generalized anxiety disorder.
The authors concluded that these findings suggest that Toxoplasma gondii infection is “strongly and significantly” associated with GAD [generalized anxiety disorder]
As for autism, there is a body of evidence that the parasite Toxoplasma gondii may be an underlining cause of autism and be worth ruling out.
In the medical journal Microbial Pathogenesis, a study from 2020 showed that toxoplasmosis plays a vital role as a risk factor for autism.
References
https://pubmed.ncbi.nlm.nih.gov/25124709/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4809231/
https://pubmed.ncbi.nlm.nih.gov/32777351/