The Reporter: Dec 1994, Vol.5, No.4
Research Focuses on Suicide

Suicide is the eighth leading cause of death among adults and the second or third leading cause of death among adolescents, but having a psychiatric illness does not automatically predict likelihood for suicidal behavior.

"Rather, there are biological factors that differentiate those who attempt to take their lives from those who do not," explains Dr. John Mann, P&S professor of psychiatry and director of neuroscience at the New York Psychiatric Institute and of the Mental Health Clinical Research Center for the Study of Suicidal Behavior, which draws on the disciplines of neurochemistry, neuropathology, and brain imaging.

Dr. Mann joined P&S and the Psychiatric Institute July 1 after serving as director of the University of Pittsburgh's neuropharmacology laboratories.

Studying these biological factors has been Dr. Mann's focus for more than 11 years. For the past five years he has been the principal investigator of the only federally funded center on suicidal behavior across the life cycle. "We've learned from earlier work that alteration in the serotonin system, which is under significant genetic control, may be a predictor for suicidal behavior," says Dr. Mann. He and his research team recently improved understanding of site-specific activity in the brain and directed their efforts to study abnormalities in the lateral and orbital prefrontal cortex. This is based on knowledge that individuals, after sustaining injuries to the prefrontal cortex, often are less inhibited from acting and speaking inappropriately.

A specific biological abnormality appears to be associated with many psychiatric disorders and correlates with a vulnerability for suicide. Depressed patients may exhibit the same severity and number of episodes of illness, but members of a high-risk group (group A) may make lethal attempts to end their lives while members of a low-risk group (group B) do not.

"The serotonin system in group A may be blunted. Often the high-risk group tends to be undermedicated. We need to distinguish the characteristics of the high-risk group from the low-risk group then work toward a clinical recommendation," says Dr. Mann.

Throughout his years of research, Dr. Mann and his colleagues, Dr. Victoria Arango and Dr. Mark Underwood, have developed a method of looking at biochemical activity by examining slices of brain tissue obtained during autopsy at a resolution many times greater than that allowed by a PET scanner. The resolution permits examination of the serotonin activity at the cellular level.

"We are conducting postmortem research comparing the brain tissue of suicide victims with those suffering non-self-inflicted trauma as well as interviewing families in order to determine a diagnosis," says Dr. Mann. "One factor may not be sufficient to predispose an individual to act on suicidal tendencies."