Acute tryptophan depletion and self-injurious behavior in aggressive patients and healthy volunteers
- First Online:
- 200 Downloads
An association between serotonin (5-HT) activity and self-injurious (i.e., self-aggressive) behavior across the spectrum of lethality (from self-mutilation through completed suicide) is a well-replicated finding. Studies to date, however, have relied on nonexperimental designs to examine this relationship, limiting the causal inferences that can be drawn about the role of 5-HT in self-aggressive behavior.
Examine the effect of experimentally altered 5-HT activity (via dietary tryptophan depletion) on self-aggressive behavior among adults with and without intermittent explosive disorder (IED). Individuals with a marked history of aggression, such as those with IED, are characterized by compromised 5-HT and heightened risk for self-aggression, making this a population of interest for examining the proposed relations.
Materials and methods
IED patients (n = 16) and healthy controls (n = 16) received a tryptophan depletion and a placebo drink on separate days at least 1 week apart. Self-aggressive behavior was assessed on both study days using a well-validated laboratory-based behavioral assessment with self-aggression defined as the intensity of shock self-administered.
Tryptophan depletion facilitated selection of more intense shocks, on average, in both groups. Patients with IED were also more self-aggressive overall than healthy volunteers. No IED by drink condition interactions were found.
Experimentally lowered 5-HT bioavailability enhances overall self-injurious behavior irrespective of aggression history.
KeywordsSelf-aggression Serotonin Tryptophan depletion Intermittent explosive disorder
- CDC (2005) Web-based Injury Statistics Query and Reporting System (WISQARS). Available at http://www.cdc.gov/ncipc/wisqars/
- Coccaro EF (2003) Intermittent explosive disorder. In: Coccaro EF (ed) Aggression: psychiatric assessment and treatment. Marcel Dekker, New York, pp 149–199Google Scholar
- First MB, Gibbons M, Spitzer RL, Williams JBW (1996) User’s guide for the SCID-I (Research Version). Biometrics Research, Biometrics ResearchGoogle Scholar
- Joiner TE (2005) Why people die by suicide. Harvard University Press, CambridgeGoogle Scholar
- Lopez-Ibor JJ Jr, Saiz-Ruiz J, Perez de los Cobos JC (1985) Biological correlations of suicide and aggressivity in major depressions (with melancholia): 5-hydroxyindoleacetic acid and cortisol in cerebral spinal fluid, dexamethasone suppression test and therapeutic response to 5-hydroxytryptophan. Neuropsychobiology 14:67–74PubMedCrossRefGoogle Scholar
- McCloskey MS, Coccaro EF (2003) Questionnaire and interview measures of aggression in adults. In: Coccaro EF (ed) Aggression: psychiatric assessment and treatment. Marcel Dekker, New York, pp 167–193Google Scholar
- Pfohl B, Blum N, Zimmerman M (1995) Structured clinical interview for DSM-IV personality. In: Pfohl B, Blum N, Zimmerman M (eds) Structured clinical interview for DSM-IV personality. University of Iowa College of Medicine, Iowa CityGoogle Scholar