Brain enzyme known to affect mood may be decreased in teens who commit suicide

The activity of a brain enzyme known to affect mood may be decreased in teens who commit suicide, according to an article in the July issue of The Archives of General Psychiatry.

According to the article, approximately 30,000 people die of suicide in the United States annually, and suicide is the second leading cause of death among teenagers. While there is some understanding about the psychological and psychosocial factors associated with teenage suicide, little is known about neurobiological factors that may contribute to teenage suicide. An enzyme in the brain called protein kinase C (PKC) has been linked with mood disorders, and it is the target of some mood-stabilizing drugs.

Ghanshyam N. Pandey, Ph.D., of the University of Illinois at Chicago, and colleagues investigated whether there was any link between changes in PKC and teenage suicide.

The researchers examined the brains of 17 teenage suicide victims and compared them to 17 brains of teenagers without psychiatric illness who did not commit suicide as their cause of death (control subjects). The brains were obtained from the Brain Collection Program of the Maryland Psychiatric Research Center, in collaboration with the Medical Examiner’s Office of the State of Maryland). PCK activity was measured from samples of PKC taken from each brain.

Of the 17 suicide victims, nine had a history of mental disorders, and eight had no history of mental disorders, although two had a history of alcohol or drug abuse. There were 16 males and one female in the control group, and among suicide victims, ten were male and seven were female.

The researchers found that protein kinase C activity was statistically significantly decreased in measurements in certain brain areas in teenage suicide victims’ brains compared with measurements from the brains of control subjects.

“Because many physiologic functions are mediated through [PKC activity] and because PKC is a target for the therapeutic action of psychoactive drugs, our findings indicate that the pathogenesis of teenage suicide may be associated with abnormalities on PKC and that PKC may be a target for therapeutic intervention in patients with suicidal behaviors,” the authors write.