EMBARGOED UNTIL FEBRUARY 6:  

SUICIDAL BEHAVIOR MAY BE LINKED TO PROBLEMS IN CANNABINOID SYSTEM

Anandamide, a naturally occurring brain lipid, has been shown to bind to cannabinoid CB1 receptors in the brain and mimic the effects of the active ingredient in marijuana. Chronic alcohol has been shown to increase the brain levels of anandamide and reduce the CB1 receptor density in the rodent brain. Knowing the mood and cognition altering ability of cannabinoids and alcohol, and the association between depression and alcohol abuse to suicide, scientists at the New York State Psychiatric Institute (NYSPI) and Nathan Kline Institute (NKI) became interested in the role of the cannabinoid system in depression and suicide. Now, for the first time researchers have linked the CB1 receptors to depression and suicide.

The new finding is reported in the February issue of Molecular Psychiatry. Dr. Appa Hungund and colleagues examined the prefrontal cortices of 10 individuals who had a lifetime diagnosis of major depression and who committed suicide (age 13-77) and 10 non-suicide controls (age 15-79). CB1 receptor density and cannabinoid signaling (function) were significantly higher in the prefrontal cortex of those who had committed suicide versus those in the control group.

The prefrontal cortex is the region in the brain that is linked to aggression and impulsivity, behaviors common in suicide attempters. The study was conducted with the post-mortem human brain tissue provided by Drs. Victoria Arango and John Mann from their brain tissue collection at NYSPI.

“Our findings suggest that the cannabinoid system may be working in concert with the serotonergic and adrenergic systems to provoke suicide in individuals with major depression,” said Dr. Hungund and Dr. Vinod Yaragudri of NKI, another collaborator on this study. “Therefore, drugs targeting the cannabinoid system may have therapeutic value in the treatment of suicidal and depressive behaviors.”

Noting the difficulties in determining whether the abnormalities found in the prefrontal cortex could be attributed to the presence of major depression or were a result of the suicidal act, itself, the authors wrote: “…future studies should test for the differences between suicide victims with a history of major depression and non-depressed suicides and or depressed and normal subjects who died by similar cause of death.”

Go Back to News Releases