Controlling your anger and reacting sensibly when someone treats you badly can be a problem. And if you have low levels of serotonin, it can be even more of a problem, a new study has found. Molly Crockett at the University of Cambridge, UK, and her colleagues gave volunteers a drink that temporarily lowered their levels of serotonin, a brain ‘neurotransmitter’ linked to happy mood. They then had them play ‘the Ultimatum Game’, which involves accepting or rejecting offers of money. Those with lower serotonin levels showed increased retaliation to offers that they perceived to be unfair. “We’ve suspected for years that there’s a link between serotonin and impulsive aggression and emotional regulation,” says Crockett. “Until this study it wasn’t clear whether serotonin was playing a causal role.”
It has long been known that low serotonin levels are associated with groups of people prone to impulsiveness and problems with emotional control, such as alcoholics, violent criminals and suicide attempters. Low serotonin is also found in clinical conditions such as depression and anxiety.