August 17, 2012
Some Suicide Attempts May Be Blamed On Parasite
Lee Rannals for redOrbit.com — Your Universe Online
A parasite may be to blame for some suicide attempts, according to research appearing in the Journal of Clinical Psychiatry.Toxoplasma gondii, or T. gondii, lies in the bodies of 10 to 20 percent of Americans, but in most it was thought to lie dormant. However, it appears as though the parasite can cause inflammation over time, which produces harmful metabolites that can damage brain cells.
“Previous research has found signs of inflammation in the brains of suicide victims and people battling depression, and there also are previous reports linking Toxoplasma gondii to suicide attempts," Lena Brundin, an associate professor of experimental psychiatry in Michigan State University's College of Human Medicine, said in a press release.. “In our study we found that if you are positive for the parasite, you are seven times more likely to attempt suicide.”
The researchers found that those infected with T.gondii scored higher on the scale, which indicates a more severe disease and greater risk for future suicide attempts.
“Some individuals may for some reason be more susceptible to develop symptoms,” she said, but not all individuals infected will attempt suicide.
“Suicide is major health problem,” Brundin said in the release. “It is estimated 90 percent of people who attempt suicide have a diagnosed psychiatric disorder. If we could identify those people infected with this parasite, it could help us predict who is at a higher risk.”
The cell is transmitted to humans primarily through ingesting water and food contaminated with the eggs of the parasites.
Brundin said she has been looking for the link between depression and inflammation in the brain for a decade, beginning with work she did on Parkinson's disease. Typically, a class of antidepressants called selective serotonin re-uptake inhibitors (SSRIs) have been the preferred treatment for depression.
SSRIs are believed to increase the level of a neurotransmitter called serotonin, but are effective in only about half of depressed patients.
The team's research indicates a reduction in the brain's serotonin might be a symptom rather than the root cause of depression. Inflammation likely causes changes in the brain's chemistry, leading to depression and some thoughts of suicide.
“I think it´s very positive that we are finding biological changes in suicidal patients,” she said in the release. “It means we can develop new treatments to prevent suicides, and patients can feel hope that maybe we can help them.
“It´s a great opportunity to develop new treatments tailored at specific biological mechanisms.”