Behavioral response to methylphenidate challenge: Influence of early life parental care

Abstract

Rat studies have shown that pups subjected to suboptimal rearing conditions exhibited permanently dysregulated dopamine activity and altered behavioral responses to dopamine stimulation. In humans, heightened stress-induced mesoaccumbens dopamine release in adults reporting low maternal care experience has been shown. We explored the relationship between quality of parental care and behavioral responsivity to reward and 20 mg of the dopamine agonist methylphenidate (MPH). Forty-three male university students accomplished a monetarily rewarded card-sorting task in a placebo controlled between-subjects study design. In participants scoring above the cut-off score for high parental care as assessed by the Parental Bonding Inventory, MPH decreased performance accuracy in the reward condition of the task. Contrarily, reward-induced performance accuracy of low care participants was enhanced with MPH. Activity measures in response to reward and MPH were uninfluenced by parental care. This is the first human study to reveal that the behavioral MPH response interacts with early life parental care experience.