People who are prone to seeking excitement and acting impulsively may have differences in the structure of their brains, which may also predispose them to substance abuse, a new study has found.
Scientists found that increased impulsivity and sensation-seeking in healthy young adults was linked to distinct differences in their brain structures – the areas involved in decision-making and self-control had a thinner cortex, the brain’s wrinkled outer layer or gray matter.
Researchers from Yale University, Harvard University and Massachusetts General Hospital examined the variability in brain structure among 1,234 males and females aged 18 to 35 with no history of psychiatric disorders or substance dependence.
Using magnetic resonance imaging (MRI), they measured the size of particular regions of the brain for each participant.
The participants also completed questionnaires assessing traits associated with sensation-seeking and impulsivity such as their need for novel and intense experiences, willingness to take risks, and a tendency to make rapid decisions.
They also reported alcohol, tobacco and caffeine usage.
Researchers found that people who reported seeking high levels of stimulation or excitement had reduced cortical thickness, or gray matter, in brain regions associated with decision making and self-control.
The strongest links occurred in brain areas related to the ability to regulate emotions and behaviour, the anterior cingulate and middle frontal gyrus.
Changes in those brain structures also correlated with participants’ self-reported tendency to act on impulse and with heightened use of alcohol, tobacco, or caffeine.
“The findings allow us to have a better understanding of how normal variation in brain anatomy in the general population might bias both temperamental characteristics and health behaviours, including substance abuse,” said Avram Holmes from Yale University.
The findings were published in The Journal of Neuroscience.