High dopamine triggers risk-taking behaviour

Boosting the levels of brain chemical dopamine can lead to increased risk-taking among people, says new research.

The study, led by Robb Rutledge at University College London, found that increasing dopamine levels in healthy adults led participants to choose more risky options in a gambling task.

For the study, 30 healthy adults performed a gambling task on two separate occasions, once after receiving a dopamine drug and once after receiving a placebo.

Rutledge found that participants took more risks to try to get bigger rewards after receiving dopamine but not placebo.

"After receiving the drug, subjects chose more risky options regardless of how much larger the potential reward was compared to the safe alternative," the authors said in a paper published in the Journal of Neuroscience.

Dopamine is involved in reward learning and previous research has linked dopamine drugs with compulsive gambling problems in people with Parkinson's disease.

The researchers proposed that dopamine made potential rewards more appealing but did not affect subjects' perception of potential losses.

They also speculated that, while on the drug, subjects might experience similar dopamine release for all reward levels which would explain why they were similarly happy after small and large rewards.

"This study sheds light on dopamine's effects on decision-making and emotion," said Nathaniel Daw, neuroscientist at New York University who was not involved in the study.

The results "may help to explain some kinds of gambling and impulse control problems and also aspects of mood disorders".