Serotonin, dopamine and addiction
Lower levels of brain 5-hydroxytryptamine (5-HT) have been associated with impulsive and aggressive traits, which in turn are related to increased levels of stimulant misuse. Cox et al (pp. 391–397) used neurochemical imaging to demonstrate that lowering 5-HT levels leads to an increase in cocaine-induced craving and striatal dopaminergic response, a possible mechanism for increased drug-seeking behaviour. In an accompanying editorial, Nutt (pp. 353–354) questions the clinical implications of this finding, commenting on the lack of effect of selective serotonin reuptake inhibitors as anti-addiction agents. He also raises the questions of whether 5-HT may also modulate other neurotransmitters and influence the use of other drugs, and whether one should also examine the role of well-established genetic variation in 5-HT reuptake sites.