Scientists have found a mysterious link between a cat parasite and increased suicidal tendencies in people,especially in women,a finding they say could help predict those at greater risk of attempting to kill themselves and also find ways to intervene.
Psychiatrists at the University of Maryland School of Medicine found that women infected with the parasite,called Toxoplasma gondii,are more likely to attempt suicide than non-infected women. However,the reason for this connection still remains a mystery.
T-gondii is a protozoa that prefers to infect cats,but humans can pick up the parasite from contact with cat feces,or by eating infected meat or vegetables. Once ingested,the parasite can make a home for itself inside the person’s brain and muscle tissues,protected inside cysts that are resistant to attacks by the host’s immune system,the researchers said.
Some studies have linked infection by this parasite with a variety of mental health and brain problems. But they aren’t clear on whether the parasite contributes to these problems or is a mere side effect.
The new study also has the same limitation. Researchers can’t say for sure whether the parasite somehow drives people to suicide. But in women with infections,they found,the risk of an attempt is 1.5 times greater than in women without.
“We can’t say with certainty that T-gondii caused the women to try to kill themselves,but we did find a predictive association between the infection and suicide attempts later in life that warrants additional studies,” lead author TeodorPostolache was quoted as saying by LiveScience.
In the study,Postolache and his team looked at 45,788 Danish women whose newborns had been screened for T-gondii antibodies between 1992 and 1995 (a positive result was a sure sign that mom was infected). About a quarter of the women had been infected at the time of delivery,the results revealed.
The researchers then combed through all of the women’s records for suicide attempts and found about 517 of them had tried to kill themselves,with 78 of these women attempting violent methods. Of the 18 succeeded in killing themselves,eight had T-gondii infections.
The statistics showed that women who were infected with the parasite were 1.8 times more likely to attempt suicide by violent means than uninfected women. The researchers were able to control for diagnoses of mental illness,meaning that infection was independently linked to suicide attempts,not just to mental health problems in general.
However,Postolache said more studies are needed to determine if the parasite somehow causes suicide attempts or self-harm.
If the parasite is found to be a cause,the next mystery to unravel will be how,Postolache said. It could be that the parasite acts directly on the brain in a way that promotes mental illness. Or perhaps it triggers the immune system to attack the brain somehow.
“If we can identify a causal relationship,we may be able to predict those at increased risk for attempting suicide and find ways to intervene,” Postolache said.