It depends on how fast it reaches the brain
STUDY: Bieś R et al, Pharmaceuticals 2026
STUDY TYPE: Systematic review (35 studies)
FUNDING: WSB University and the Medical School of Silesia
Background
Methylphenidate blocks dopamine and norepinephrine reuptake at the same transporter cocaine acts on. This review asked when, if ever, it causes addiction.
The Study
- 35 studies, including randomized controlled trials, PET imaging studies, population surveys, case reports, and animal research.
- Participants included healthy volunteers, people with ADHD, and people with cocaine or other substance use disorders.
- Outcomes were drug liking, craving, tolerance, withdrawal, misuse, and abuse. The studies were too varied to pool.
Results
Patients taking it as prescribed showed no rise in addictive behavior. Although prescription rates have risen in past 10 years, this hasn’t been followed by a rise in stimulant addiction.
The speed of delivery determined the rewarding sensation. Immediate-release and OROS (Concerta) eventually blocked the dopamine transporter to the same degree, yet only immediate-release produced significant drug-liking. Snorted and intravenous doses produced the highest “drug liking” and “take drug again” ratings. In one trial, volunteers rated 54 mg of OROS no more rewarding than placebo.
Cravings mainly showed up when the brain was already sensitized by prior addiction to similar drugs. Intravenous methylphenidate triggered craving in people with cocaine dependence but only a “high” in healthy volunteers.
Misuse and abuse clustered in three groups:
- People without a prescription or ADHD, usually taking it to stay focused and alert
- Patients with ADHD plus conduct disorder or a substance use disorder
- People snorting or injecting high doses, often as a cocaine substitute
Tolerance developed in a subset of patients (in one review, tolerance occurred to the energizing, mood-elevating, rewarding effects but not to the ADHD benefits). In these patients, higher doses usually failed to restore benefit while adding side effects. Withdrawal was mild: stopping mostly brought ADHD symptoms back. A few case reports described cramps, dystonia, or priapism on drug-free days.
Much of the evidence comes from case reports and short experiments, and long-term data in adults are scarce.
Practice Implications
- This study applies to methylphenidate, but caution that amphetamines have more potent effects on dopamine and greater rewarding properties.
- Taken by mouth as prescribed, methylphenidate carries a low addiction risk.
- Faster routes bring greater risks: immediate-release, high doses, snorting, or injection.
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
