Serotonin and dopamine play complementary roles in gambling to recover losses

Daniel Campbell-Meiklejohn (1) , Judi Wakeley (1) , Vanessa Herbert (1) , Jennifer Cook (1) , Paolo Scollo (1) , Manaan Kar Ray (1) , Sudhakar Selvaraj (1) , Richard E Passingham (1) , Philip J. Cowen (1) , Robert D Rogers (1)

1 Department of Psychiatry

ABSTRACT Continued gambling to recover losses  'loss-chasing'  is a prominent feature of social and pathological gambling. However, little is known about which neuromodulators influence this behaviour. In 3 separate experiments, we investigated the role of serotonin activity, D2/D3 receptor activity, and beta-adrenoceptor activity on the loss-chasing of age and IQ-matched healthy adults randomised to treatment or an appropriate control/placebo. In Experiment 1, participants consumed amino acid drinks that did or did not contain the serotonin precursor, tryptophan. In Experiment 2, participants received a single 176µg dose of the D2/D3 receptor agonist, pramipexole, or placebo. In Experiment 3, participants received a single 80mg dose of the beta-adrenoceptor blocker, propranolol, or placebo. Following treatment, participants completed a computerised loss-chasing game. Mood and heart rate was measured at baseline and following treatment. Tryptophan depletion significantly reduced the number of decisions made to chase losses, and the number of consecutive decisions to chase, in the absence of marked changes in mood. By contrast, pramipexole significantly increased the value of losses chased and diminished the value of losses surrendered. Propranolol markedly reduced heart rate but produced no significant changes in loss-chasing behaviour. Loss-chasing can be thought of as an aversively motivated escape behaviour controlled, in part, by the marginal value of continued gambling relative to the value of already accumulated losses. Serotonin and dopamine appear to play dissociable roles in the tendency of individuals to gamble to recover or to seek to 'escape' from previous losses. Serotonergic activity seems to promote the availability of loss-chasing as a behavioural option, while D2/D3 receptor activity produces complex changes in the value of losses judged worth chasing. Sympathetic arousal, at least as mediated by beta-adrenoceptors, does not play a major role in loss-chasing choices.

Mots clés: Addiction & Substance Abuse; Behavioral Science; Dopamine; Serotonin; gambling; loss-chasing; persistence; value

Daniel Campbell-Meiklejohn, Judi Wakeley, Vanessa Herbert, Jennifer Cook, Paolo Scollo, et al.. Serotonin and dopamine play complementary roles in gambling to recover losses. Neuropsychopharmacology, 2010, ⟨10.1038/npp.2010.170⟩. ⟨hal-00587263⟩