Methylphenidate, the active compound in the drug Ritalin, can enhance the way the brain responds to further exposure to the drug and can cause increased amphetamine-seeking behaviour in rats when self-administered. The findings reported in this week’s Nature Communications reveal hidden side-effects of a prescribed drug that is also used for recreational purposes.

In the Western world, methylphenidate is commonly prescribed for attention deficit/hyperactivity disorder (ADHD) and narcolepsy, but is also taken for recreational use due to its reported cognitive-enhancing and euphoric effects. However, available information on the neurobiological implications of recreational methylphenidate consumption is limited. To address this issue, Sara Jones and colleagues allow rats to self-administer methylphenidate and find that this activity causes increases in the levels of dopamine transporter proteins, which is heavily implicated in addictive behaviours. They further show that the methylphenidate-induced increase in dopamine transporter levels is directly linked to an increase in drug-seeking behaviour towards methylphenidate, as well as drugs with similar properties, such as amphetamines.

The authors suggest that individual variations in dopamine transporter levels in the human population, which are observed in ADHD and post-traumatic stress disorder patients, may predict susceptibility to abuse of compounds such as methylphenidate and amphetamines. However, further studies on human populations will be needed to validate this.