Psychopharmacology

, Volume 205, Issue 3, pp 349–368

The effect of increased serotonergic neurotransmission on aggression: a critical meta-analytical review of preclinical studies

Authors

    • Behavioral Neuroscience Program, Department of PsychologyNortheastern University
  • Lesley A. Ricci
    • Behavioral Neuroscience Program, Department of PsychologyNortheastern University
  • Glen A. Coppersmith
    • Behavioral Neuroscience Program, Department of PsychologyNortheastern University
  • Richard H. MelloniJr.
    • Behavioral Neuroscience Program, Department of PsychologyNortheastern University
Review

DOI: 10.1007/s00213-009-1543-2

Cite this article as:
Carrillo, M., Ricci, L.A., Coppersmith, G.A. et al. Psychopharmacology (2009) 205: 349. doi:10.1007/s00213-009-1543-2

Abstract

Rationale

The role of serotonin (5-HT) on aggression has been extensively studied; nonetheless, the role of this neurotransmitter in aggression is still inconclusive.

Objectives

The current meta-analytical review investigated the role of increased 5-HT neurotransmission in aggression.

Methods

Preclinical studies using serotonin reuptake inhibitors, 5-hydroxytryptophan, l-tryptophan, or serotonin (5-HT) to increase 5-HT levels were included in this meta-analysis. An overall effect of serotonin on aggression was calculated, and the role of several moderator variables was analyzed.

Results

A total of 218 effect sizes revealed that increased 5-HT had an overall significant inhibitory effect on aggression (r = 0.3). The results showed that increased 5-HT had the strongest inhibitory effect on aggression when (1) a specific strain or species (e.g., Long Evans) was used; (2) aggression was offensive or predatory and/or induced by administration of 5,7-dihydroxytryptamine or p-chlorophenylalanine; (3) zimelidine, sertraline, l-tryptophan, citalopram, or 5-HT were used to increase 5-HT; (4) treatment was acute; (5) long chronic treatment durations were used; and (6) time between last injection and behavior testing was within 8 h before or after peak plasma concentration of drug. In contrast, the results revealed that increased-5-HT-facilitated aggression could be predicted when (1) Wistar rats, (2) social isolation or stress to induce aggression, and/or (3) animals treated for less than 3 weeks were used.

Conclusions

Although 5-HT has an overall inhibitory effect on aggression, the animal's genetic background, drug, treatment time, aggression inducing paradigm, and aggression type are critical variables that influence and modify this effect.

Keywords

SerotoninMeta-analysisAggressionPreclinical

Copyright information

© Springer-Verlag 2009