The activity of a key enzyme linked to mood disorders and the action of some mood stabilizing drugs appears to be decreased in the brains of teenagers who die by 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, with suicide the second leading cause of death among teenagers. Although 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. The enzyme called protein kinase C has been linked with mood disorders, and it is the target of some mood-stabilizing drugs.

Ghanshyam N. Pandey, Ph.D., and his American colleagues investigated whether there was any link between changes in enzyme activity and teenage suicide by examining the brains of 17 teenage suicide victims and brains of 17 teenagers without psychiatric illness who did not commit suicide.

Of the 17 suicide victims, 9 had a history of mental disorders and 8 had no history of mental disorders, although 2 had a history of alcohol or drug abuse. There were 16 males and 1 female in the control group; among the suicide victims, 10 were male and 7 were female.

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

"Because many physiologic functions are mediated through protein kinase C activity and because protein kinase C 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 protein kinase C and that protein kinase C may be a target for therapeutic intervention in patients with suicidal behaviors," the authors wrote.