Genes to blame for impulsive choices: study

Washington: The tendency to take a smaller reward now rather than waiting for a larger one available later is strongly influenced by genetics, which means it can be inherited, a new study has found. Researchers at the Washington University School of Medicine studied 602 twins and found that such 'delay discounting' gradually improves as teens get older, such that 18 year-olds have a greater ability or tendency to wait for the larger delayed reward, as compared to younger teens.

Apart from age, genes accounted for about half of the difference among individuals in their level of delay discounting, researchers said. Preliminary data suggest that these 'impulsivity genes' may include genes coding for enzymes that synthesise the neurotransmitter serotonin and receptors where serotonin binds in the brain.

"It is tantalising to speculate that the associations between delay discounting and serotonin-related genes may ultimately point the way to new treatments for addictions and other disorders involving impulsive choice," said Andrey Anokhin from Washington University School of Medicine. Researchers are analysing DNA and using questionnaire responses from as many as 25,000 human subjects in order to identify specific genes involved in delay discounting.

Identifying the 'delay discounting' genes, and the proteins they code for, will be important for understanding the basis of a variety of psychiatric disorders, especially addictions and other disorders that involve impulsive decision-making, researchers said.