Serotonin Receptors Offer Clue to Teen Suicide Risk

During the past 15 years or so, several investigators have found an abnormally large number of receptors for the nerve transmitter serotonin in the prefrontal cortex region of the brains of adults who have committed suicide.

This finding implies that those receptors might play a role in suicide susceptibility, especially since the prefrontal cortex is involved in judgment, planning, and decision making and since other types of research have also implicated serotonin in suicide.

Now an abnormally large number of serotonin receptors has also been found in the prefrontal cortexes of teens who have killed themselves, once again suggesting that the receptors might play some role in suicide vulnerability.

The discovery comes from Ghanshyam Pandey, Ph.D., of the Psychiatric Institute of the University of Illinois at Chicago, and his colleagues and is reported in the March American Journal of Psychiatry.

Pandey and his coworkers compared the brains of 15 teens who had committed suicide with the brains of 15 psychologically normal teens who had died from other causes. Pandey and his colleagues found significantly more serotonin receptors in the prefrontal cortex of brains taken from teens who had killed themselves than in the prefrontal cortex of brains taken from the teens who had been psychologically normal. The difference, they wrote in their study report, was “striking,” and “the observation of a higher level of [such] receptors in the prefrontal cortex of teenage suicide victims is similar to that observed in adults in previous studies.”

But Pandey and his team found something else intriguing as well in the prefrontal cortex from the brains of teens who committed suicide as compared with the prefrontal cortex of controls. And that was a greater expression of the messenger RNA molecules that make the proteins that in turn comprise the serotonin receptors, as well as a greater expression of the proteins themselves. This finding, Pandey explained in an interview, implies that the reason why there are so many serotonin receptors in the prefrontal cortex of the brains of teens who died by suicide may be because something has gone amok at the levels of gene transcription and translation for the proteins that make up the receptors.

But what might have gone awry? Is the prefrontal cortex’s tendency to make too many serotonin receptor proteins inherited?

“The answer is yes and no,” Pandey said. “The reason is that it can be familial, but also the transcription can be influenced by other factors as well.”

In any event, an abnormally high number of serotonin receptors in the prefrontal cortex may indicate an increased vulnerability to commit suicide. Also, there is reason to believe that if an excess of serotonin receptors is found in a person’s blood platelets, it might mirror an excess of such receptors in his or her prefrontal cortex and the person’s vulnerability to committing suicide. The reason? An excess of serotonin receptors has been found in the platelets of suicidal patients.

Thus, might it be possible to screen seriously depressed teens, or adults, for abnormally high levels of platelet serotonin receptors in hopes of pinpointing those teens, or adults, who have abnormally high levels of prefrontal cortex serotonin receptors and who might be in particular danger of killing themselves? “The answer is yes,” Pandey said.

Yet when Psychiatric News asked whether any physicians are doing such screening, he replied: “No one is doing it at a clinical level at this time.”

The study, “Higher Expression of Serotonin 5-HT2A Receptors in the Postmortem Brains of Teenage Suicide Victims,” is posted on Web at http://ajp.psychiatryonline.org/cgi/content/abstract/159/3/419?. ▪