5-Hydroxytryptamine 1A Receptors, Major Depression, and Suicidal Behavior

Background Several lines of evidence suggest a clear relationship between serotonin (5-hydroxytryptamine, 5-HT) hypoactivity and suicidal behavior across several psychiatric diagnoses. Few data are available, however, regarding the possible specific role of 5-HT1A receptors in the biology of suicidality. Therefore, the aim of our study was to use a neuroendocrine strategy to test the hypothesis of a role for 5-HT1A receptors in the biology of suicidal behavior. Methods Hormonal (adrenocorticotropic hormone [ACTH], cortisol, prolactin [PRL]) and temperature responses after administration of flesinoxan, a highly potent and selective 5-HT1A receptor full agonist, were assessed in 40 inpatients with major depression, divided into two subgroups (20 suicide attempters and 20 nonattempters), compared with 20 normal control subjects matched for gender and age. Results Compared with nonattempters, suicide attempters exhibited significantly lower PRL ( p = .01), cortisol ( p = .014), and temperature ( p = .0002) responses. Prolactin ( p = .007), cortisol ( p = .04), and temperature ( p = .00003) responses were also decreased in suicide attempters compared with normal control subjects. In contrast, we did not observe any significant differences in hormonal or temperature responses to flesinoxan between depressed patients without a history of suicide attempt and normal control subjects. Conclusions The present study tends to confirm the role of 5-HT and more specifically 5-HT1A receptors in the biology of suicidal behavior in major depression.