A drug used to treat those with attention deficit hyperactivity disorder may prevent the depletion of self-control, according to a recent study.

Researchers from the University of Michigan found that Methylphenidate, also known as Ritalin, may help preserve self-control resources.

Exerting self-control - the ability to control one's emotions, behavior, and desires - for a long period seems to "deplete" the ability to exert self-control effectively on subsequent tasks, researchers said.

"It is as if self-control is a limited resource that 'runs out' if it is used too much," lead researcher Chandra Sripada of the University of Michigan said in a statement. "If we could figure out the brain mechanisms that cause regulatory depletion, then maybe we could find a way to prevent it."

For the study, researchers tested 108 adult participants, all of whom took a drug capsule 60 minutes prior to testing.

Half of the participants received a capsule that contained methylphenidate, a medication used to treat ADHD that increases brain dopamine and norepinephrine. The other half received a placebo capsule. Participants were then completed a computer-based task in "which they were required to press a button when a word containing the letter e appeared on screen. Some were given modified instructions that asked them to refrain from pressing the button if the letter e was next to or one extra letter away from another vowel - this version of the task was designed to tax participants' self-control.

Researchers found that participants who received the placebo and performed the taxing version of the first task showed greater variability in how quickly they responded in the second task, compared to those whose self-control hadn't been depleted in the first task.

Bur for those who received the methylphenidate capsule, the first task didn't have an effect on later performance - the methylphenidate seemed to counteract the self-regulatory depletion incurred by the harder version of the first task.

"These results indicate that depletion of self-control due to prior effort can be fully blocked pharmacologically," Sripada said. "The task we give people to deplete their self-control is pretty cognitively demanding, so we were surprised at how effective methylphenidate was in blocking depletion of self-control."

Based on the results, researchers suggest that methylphenidate may help to boost performance of the specific circuits in the brain's prefrontal cortex that are normally compromised after sustained exertion of self-control.

However, Sripada said it doesn't mean that people looking to boost self-control should go out and buy Ritalin.

"Methylphenidate is a powerful psychotropic medicine that should only be taken with a prescription," Sripada said. "We want to use this research to better understand the brain mechanisms that lead to depletion of self-control, and what interventions - pharmacological or behavioral - might prevent this."

The findings were recently published in Psychological Science, a journal of the Association for Psychological Science.