Research: Risky behaviour

1 December 2005

People misusing drugs show abnormal brain activity during an experimental test of risk-taking behaviour – and abnormalities are still seen a year after individuals have given up drugs.

Long-term misuse of drugs such as amphetamines (e.g. speed) and opiates (e.g. heroin) appears to affect people’s decision-making abilities, probably by disrupting the function of neural circuits in the brain's frontal lobe.

Barbara Sahakian and colleagues in Cambridge explored this further in functional imaging studies of amphetamine and opiate users, former users, and matched controls. Individuals were scanned while undertaking a task in which they had to choose between an unlikely high reward and a likely low reward.

In control participants, activation was greatest in the right dorsolateral prefrontal cortex, whereas in drug users the left orbitofrontal cortex was favoured. Moreover, this difference was also seen in the individuals who had been off drugs for at least a year.

External links

• Ersche KD et al. Abnormal frontal activations related to decision-making in current and former amphetamine and opiate dependent individuals. Psychopharmacology (Berl) 2005;180(4):612–23.