Importance: The prescribing of stimulant medications for attention-deficit/hyperactivity disorder (ADHD) has increased in the US. Prescription stimulants are one of the most commonly misused controlled substances during adolescence. Despite a 10-fold increase in stimulant-related overdose deaths in the past decade, the transitions from prescription stimulants to illicit stimulants (eg, cocaine, methamphetamine) remain relatively unknown in longitudinal population-based studies.

Question: Is adolescents’ use of stimulant therapy for attention-deficit/hyperactivity disorder (ADHD) associated with cocaine and methamphetamine use as young adults?

Findings: In this cohort study of 5034 respondents, adolescents who used stimulant therapy for ADHD did not differ from their peers in cocaine and methamphetamine use at 19 to 24 years of age. In contrast, adolescents’ prescription stimulant misuse was associated with greater adjusted odds of later cocaine and methamphetamine use compared with population controls.

Meaning: These findings suggest that adolescents’ use of stimulant therapy was not associated with increased risk for illicit stimulant use; however, prescription stimulant misuse was a signal for cocaine or methamphetamine use and warrants monitoring and screening.