Serotonergic intervention affects both social dominance and affiliative behaviour.
BACKGROUND
Deficiencies in serotonin function have been associated with irritability and aggression but enhancing serotonin has also been shown to promote social status and affiliative behaviour in non-human primates and more recently in humans.


OBJECTIVE
To investigate the effects of citalopram, a selective serotonin reuptake inhibitor (SSRI), on social behaviour with a flatmate and a stranger.


METHODS
Ten pairs of healthy volunteers took part in a randomized double-blind crossover study of 2 weeks treatment with citalopram (20 mg/day) and placebo with a 2-week washout period. In each pair, one person (subject) took the tablets and the other (flatmate) received no treatment. On the last day of each treatment period, the subjects socially interacted with a confederate behaving as a responsive person in a stranger-dyadic social interaction paradigm. After the interaction, subjects played the Mixed-motive game, which measures cooperative behaviour and communication, with the confederate. The flatmates evaluated the social behaviour of the subjects before and at the end of the treatment periods.


RESULTS
On citalopram, the subjects were rated as significantly less submissive by their flatmates and they showed a dominant pattern of eye contact in the stranger-dyadic social interaction paradigm. They also reduced the number of points they awarded themselves and sent more cooperative messages during the game.


CONCLUSIONS
These results indicate that administration of an SSRI can modify social status in different interactions and increase affiliative behaviour. They implicate a role for serotonin in modulating social aspects of behaviour.
Tse
Wai S
WS
Section of Clinical Psychopharmacology, Division of Psychological Medicine, Institute of Psychiatry, King's College, London SE5 8AF, UK. spklwst@iop.kcl.ac.uk
Bond
Alyson J
AJ
D000328:Adult; D000704:Analysis of Variance; D001519:Behavior / Q000187:drug effects*; D015283:Citalopram / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D010551:Personality / Q000187:drug effects / Q000502:physiology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D012919:Social Behavior; D013060:Speech / Q000187:drug effects / Q000502:physiology; D011795:Surveys and Questionnaires
D015283:Citalopram; D017367:Selective Serotonin Reuptake Inhibitors