Difference in serotonergic and noradrenergic regulation of human social behaviours.
BACKGROUND
Treatment with antidepressants has been shown to affect social functioning, but drugs with actions on different neurotransmitters may have a different profile of effects.


OBJECTIVE
To study the effects of acute manipulation of two neurotransmitters, serotonin and noradrenaline, on social behaviour in healthy volunteers.


METHODS
Sixty volunteers were randomly assigned to a single dose of a selective noradrenaline reuptake inhibitor, reboxetine (4 mg), a selective serotonin reuptake inhibitor, citalopram (10 mg), or placebo. They socially interacted with a confederate behaving in a non-sociable manner in a stranger-dyadic social interaction paradigm 1.5 h postdrug. Social behaviour during the interaction was video recorded by a hidden camera and subsequently analysed. After the interaction, volunteers played the mixed-motive game with the confederate. This game has been shown to measure cooperative behaviour and communication. Volunteers read a short story and rated their mood predrug and before and after the interaction.


RESULTS
Subjects on reboxetine showed reduced hand fiddling during the interaction and gave significantly more cooperative communications during the mixed-motive game. More volunteers on reboxetine were classified as cooperative players. On the reading task, the speech of subjects on citalopram showed less reduction of energy variation after the social interaction.


CONCLUSIONS
Reboxetine had clear effects on social behaviour. Noradrenaline was related to increased social engagement and cooperation and a reduction in self-focus. Citalopram had less effect on cooperative behaviour but serotonin may be associated with protection of the self from the negative consequences of social interaction.
Tse
Wai S
WS
Section of Clinical Psychopharmacology, Division of Psychological Medicine, Institute of Psychiatry, ASB, King's College London, SE5 8AF, UK. spklwst@iop.kcl.ac.uk
Bond
Alyson J
AJ
D000293:Adolescent; D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology*; D000328:Adult; D000704:Analysis of Variance; D015283:Citalopram / Q000494:pharmacology; D003299:Cooperative Behavior; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D009638:Norepinephrine / Q000502:physiology*; D000077593:Reboxetine; D012701:Serotonin / Q000502:physiology*; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D012919:Social Behavior; D013060:Speech / Q000187:drug effects / Q000502:physiology
D018759:Adrenergic Uptake Inhibitors; D015283:Citalopram; D009025:Morpholines; D009638:Norepinephrine; D000077593:Reboxetine; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors