Certain genes associated with the immune system’s inflammatory reactions may alter a healthy person’s personality traits and also increase the risk for mental illness and suicidal tendencies, according to a thesis from the University of Gothenburg, Sweden.
“Previous studies have shown that individuals suffering from various mental illnesses have an increased peripheral inflammation, but the reason behind this increase is not known,” says Petra Suchankova Karlsson, author of the thesis.
“It has been suggested that the stress that goes with mental illness activates the body’s immune system, but it is also possible that inflammation in the body affects the brain, which in turn results in mental illness.”
Prior research has focused on how environmental stressors and psychological factors trigger the immune system and how this affects the brain.
However, Suchankova’s work is the first to suggest that genes linked to the immune system may be responsible for a healthy person’s personality traits and that some of these genes are associated with an increased risk of schizophrenia or suicidal behavior.
“One of the things we studied was a gene variant that increases impulsiveness in people who carry it,” said Suchankova. “We already knew that the risk of attempting suicide is higher in impulsive people and therefore analyzed this gene variant in a group of patients who had attempted to take their life.”
“We found that these patients more often carried the particular gene variant when compared to the general population, which meant that this variant was not only associated with increased impulsiveness in healthy individuals but also with increased risk of suicidal behavior.”
The study suggests that changed levels of inflammatory substances in the blood of individuals with mental illness may have actually been caused by inflammation-related genes, rather than the illness itself leading to a change in the immune system, as originally thought.
“It could well be that some variants of the genes play a role in the development of mental illness by controlling how the brain is formed, perhaps during the embryonic stage, or by affecting the transfer of signal substances,” said Suchankova.
Source: University of Gothenburg