Biology and crime — ‘Numerous studies have shown a link between antisocial, violent crime and low serotonin metabolism in offenders. But researchers have not been able to explain why processing of this essential neurotransmitter was lowered in these individuals. Is it that serotonin?s uptake is inhibited by receptors on neurons, or is the cause found further up the metabolic chain in a possible excess of serotonin?s metabolic precursor, free L-tryptophan?

Enter scientists from the University of Kuopio, Finland….’