Research published in Psychopharmacology on December 15 suggests that methylphenidate, a stimulant drug commonly prescribed to treat attention deficit hyperactivity disorder (ADHD), can enhance some aspects of memory and other cognitive functions in health adults.
Methylphenidate prevents brain cells from re-absorbing the neurotransmitters dopamine and noradrenaline, creating a higher concentration of those neurotransmitters in the brain. It is also known by trade names Ritalin and Concerta.
Studies have found that methylphenidate reduces the symptoms of ADHD in children and adults. But studies regarding the effects of methylphenidate on cognitive processes unrelated to ADHD are relatively sparse.
For their study, researchers from The Netherlands and Switzerland investigated the effects of methylphenidate in 19 healthy participants. During the testing, participants received 10, 20 or 40 milligrams of methylphenidate and a placebo.
The researchers found that the drug improved the participants’ ability to recall a list of 30 words after thirty minutes. It did not, however, improve their ability to recall the words immediately after reading them.
The finding suggests that methylphenidate improves memory consolidation, or the coding of a memory so that it can be retrieved later.
The study did not find that methylphenidate affected spatial working memory or planning, although previous studies have found a positive effect.
“A possibly important difference between the self-ordered search tasks used in previous studies and the spatial working memory task used here is that encoding of spatial locations occurs under time pressure in the current task,” the researchers explained. “Previous research has suggested that methylphenidate may induce activity and arousal in healthy volunteers. Hence, participants may have had difficulties to encode information due to overarousal.”
The study also found that methylphenidate produced faster responses and a higher percentage of correct responses on a set shifting task, which assessed cognitive flexibility and the ability to shift attention from one stimuli to another. The drug was furthermore shown to improve motor impulsivity, or the ability to inhibit and execute behavioral responses.