Effects of early methylphenidate exposure on morphine- and sucrose-reinforced behaviors in adult rats: relationship to dopamine D2 receptors.

Methylphenidate is commonly used to treat Attention Deficit Hyperactivity Disorder (ADHD) in school-aged children, and there is an increasing trend to prescribe methylphenidate to younger preschool-aged children. While the efficacy of methylphenidate is not in question, there is evidence that early methylphenidate treatment may have long-term effects on later drug responsiveness. The goal of this study was to determine whether early exposure to methylphenidate would alter morphine-induced conditioned place preference (CPP) and sucrose-reinforced lever-pressing in young adult rats.