New research provides evidence that individual differences in dopamine levels in the brain’s putamen region can influence how methylphenidate, a widely used “smart drug,” affects our creative thinking processes. The findings, published in Neuropsychopharmacology, indicate that the use of methylphenidate can impair specific forms of creativity in those with low baseline dopamine levels.
Methylphenidate is a psychostimulant drug commonly used to treat conditions like attention deficit hyperactivity disorder (ADHD). It primarily works by increasing the transmission of neurotransmitters like dopamine and noradrenaline in the brain by blocking their transporters. Psychostimulants like methylphenidate are also sometimes used for cognitive enhancement by healthy individuals, including students, to improve focus and concentration. This study aimed to investigate the cognitive and neurochemical mechanisms underlying the effects of methylphenidate on creativity.
“My interest in the topic was piqued by the nuanced effects of psychoactive drug on different individuals,” said study author Ceyda Sayali, a postdoctoral fellow transitioning into faculty in February 2024 at Johns Hopkins University School of Medicine.
“While these drugs are often hailed for their cognitive-enhancing abilities, they are not without their drawbacks, which can vary from person to person. For instance, methylphenidate, commonly known as Ritalin, is prescribed for ADHD but is also used off-label by healthy individuals seeking cognitive improvement. Studies suggest that 4% to 16% of students use such drugs without a prescription for academic purposes. Consider a student who takes Ritalin while cramming for exams.”
“While it may sharpen focus for some, it can actually hinder performance for others, especially if their natural cognitive abilities are already well-suited to the task at hand. This ‘cognitive doping’ might not be the panacea it’s often thought to be, as these drugs are originally formulated to address specific deficits rather than to universally boost cognitive function.”
To conduct the study, the researchers recruited 90 healthy volunteers between the ages of 18 to 45. They used a double-blind, placebo-controlled, cross-over design, which means that each participant received methylphenidate, sulpiride, or a placebo on different occasions, and the order of drug administration was randomized. Sulpiride was examined alongside methylphenidate because they both impact dopamine levels in the brain.
To assess creativity, Sayali and her colleagues employed various tasks designed to measure both divergent and convergent thinking. Divergent thinking, the ability to produce multiple ideas, was evaluated using the Alternative Uses Task. Convergent thinking, the process of identifying the single best solution, was assessed using the Remote Associates Test. In addition, the participants completed the Alternate Names Task, which measured both divergent and convergent thinking by having participants generate new names for items in various categories.
In a separate session, participants underwent PET brain imaging to measure their baseline levels of dopamine synthesis capacity, particularly in the striatum. The striatum is a region located deep within the brain and is part of the basal ganglia, a group of structures that play essential roles in various motor and cognitive functions. The striatum is a key component of the brain’s reward system and is involved in regulating a wide range of functions, including movement, motivation, and decision-making.
The researchers found a significant interaction between methylphenidate and baseline dopamine synthesis capacity in the putamen region of the brain. Specifically, methylphenidate reduced response divergence (variability in types of responses generated) in participants with low baseline dopamine synthesis capacity but increased it in those with high baseline dopamine levels. This suggests that the effect of methylphenidate on creativity depended on individual differences in baseline dopamine synthesis capacity.
“From our study, it’s clear that the effects of psychoactive drugs like Ritalin are not one-size-fits-all,” Sayali told PsyPost. “Specifically, we found that performance on creative tasks—those requiring ‘out-of-the-box’ thinking—was actually impaired in healthy participants with low baseline dopamine synthesis capacity and enhanced in those with high dopamine synthesis capacity. Therefore, the notion of using these drugs as a form of ‘cognitive doping’ to universally enhance brainpower is flawed; the outcome will vary based on your unique brain chemistry and the nature of the task you’re undertaking.”
Interestingly, there were no significant effects of individual variation in dopamine synthesis capacity on creative thinking scores when participants were tested with a placebo, which suggests that the effects of dopamine on creativity may not be evident under normal conditions but may become apparent when the system is manipulated, as with methylphenidate.
“What surprised me was the lack of a direct link between baseline dopamine synthesis capacity and creative thinking in the absence of a psychoactive drug,” Sayali said. “Given the significant role that dopamine plays in the brain on cognitive functions, one might expect individuals with higher dopamine levels to naturally exhibit greater creativity.”
“However, our findings did not support this assumption. This could be due to our study not examining dopamine receptor availability, which may be a critical factor in this equation. It’s a reminder that the brain’s workings are incredibly complex, and it cautions against oversimplified assumptions regarding the influence of brain dopamine on cognitive functions.”
While this study offers valuable insights into the impact of medications on creativity, it is not without limitations. One significant limitation is that the effects of sulpiride did not surface as expected, potentially due to suboptimal dosing or timing of the creativity tasks.
“A significant caveat of our study involves the inclusion of sulpiride, a selective dopamine antagonist that specifically modulates brain activity in the striatum,” Sayali told PsyPost. “Methylphenidate, on the other hand is not selective to dopamine in the striatum but also modulates dopamine levels in the prefrontal cortex along with increasing norepinephrine levels. We used sulpiride alongside methylphenidate to further isolate the effect of striatal dopamine.”
“The lack of effect from sulpiride on creative task performance, whether alone or in relation to striatal dopamine synthesis capacity, raises questions about the specific neural mechanisms at play. Specifically, it suggests that the impact of methylphenidate on divergent creativity might be mediated by dopamine modulation in the prefrontal cortex rather than the striatum. This hypothesis remains untested in our study but could be explored in future pharmacological neuroimaging research to clarify the neural substrates of creativity.”
“We also have to consider that the reason we didn’t see any change in creativity with sulpiride might be because of when we tested for creativity after taking the drug,” Sayali explained. “It’s a bit like trying to time your coffee so that your energy peak hits right when you’re starting a brainstorming session. In our study, we asked participants to do creative tasks about 5 hours after they took sulpiride, but since this drug usually hits its highest level in the blood after about 3 hours, it’s possible that the drug wasn’t working at full strength during our creativity tests.”
The study, “Methylphenidate undermines or enhances divergent creativity depending on baseline dopamine synthesis capacity“, was authored by Ceyda Sayalı, Ruben van den Bosch, Jessica I Määttä, Lieke Hofmans, Danae Papadopetraki, Jan Booij, Robbert-Jan Verkes, Matthijs Baas, and Roshan Cools.
