Courtney L. Bagge, Ph.D.
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Small Grant Principal Investigator University of Mississippi Medical Center Jackson, Mississippi 39216
Mentors
Collaborators Kim L. Gratz, Ph.D. Maxie Gordon, M.D. Abiye H. Iyo, Ph.D. Craig A. Stockmeier, Ph.D. Matthew T. Tull, Ph.D.
Consultant Ryan Bogdan, Harvard University
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Serotonin, Impulsivity and Suicide Attempts
Given the clinical and public health significance of suicide, there is considerable interest in identifying factors that are associated with the diathesis for suicide attempts. There are well-established links between impulsivity and suicide attempts, but the nature of these associations remain unclear. One reason for this may be due to the heterogeneous nature of the construct of impulsivity, and it is largely unknown which specific facets of impulsivity relate to suicide attempts. The propensity for impulsive behavior has also been consistently linked to biological mechanisms implicated in suicidal behavior. Examining genetic associations with facets of impulsivity may provide a clearer signal in the search for serotonergic genes associated with suicide attempts. The present proposal seeks to examine the inter-relations among serotonergic genes, facets of impulsivity, and suicide attempts.
To achieve this research goal, we will employ a case-control design, recruiting 200 psychiatric inpatients (100 suicide attempters and 100 non-suicidal controls). The two-session assessment will comprise 1) a comprehensive assessment (Axis I and II diagnoses, history of suicide attempt and characteristics of attempt, and facets of impulsivity), and 2) a laboratory session where participants will complete five behavioral measures of impulsivity. At the end of the comprehensive assessment, a saliva sample will be collected in order to examine polymorphisms in serotonergic genes (Tryptophan Hydroxylase [TPH2], and 5HTT).
This study will provide preliminary data on the magnitude of the relation between polymorphisms of serotonergic genes and facets of impulsivity on suicide attempt, as well as the effect of polymorphisms of serotonergic genes on facets of impulsivity. These preliminary data and effect sizes will be used to inform the development of a larger study. Of note, an important aspect of this research is that it will establish biological, self-reported, and laboratory-based measures of distinct impulsivity processes relating to suicide attempts, as well as a suicide attempt characteristics (violent attempts). Given the high cost of suicidality to individuals and to the health care system, gaining a fine-grained understanding of impulsivity-suicide attempt associations is a critical step in allowing us to refine our theoretical models, improve our assessment tools, and suggest better treatments for suicide attempts.
