Cannabis use is a significant public health concern that disproportionately affect youth. Although promising psychosocial interventions are being developed, most youth do not benefit from these interventions alone. Given the clinical demand for effective treatments, the National Institute on Drug Abuse (NIDA) identified the critical need for data on the tolerability and potential efficacy of medications in adolescents. The purpose of this two-year study is to test if and how topiramate, a medication under intense study for treating several drugs of abuse, reduces cannabis use among teenagers. To this end, the investigators will randomize 56 nontreatment-seeking regular cannabis users (15 or 20 years old) to receive topiramate or placebo for 6 weeks. Youth will monitor their cannabis use for the 6-week period using handheld electronic diaries and complete assessments of reactivity to cannabis-related cues.

Inclusion Criteria:

• 15 to 20 years old (inclusive)
• Non-treatment seeking for cannabis abuse or dependence
• Able to read English, understand their rights as provided by the informed consent process, and be willing to sign an informed consent form to participant in the study
• If younger than 18 years old, informed consent from a parent or legal guardian is required
• Used cannabis at least 2 days per week during the past 30 days

Exclusion Criteria:

• Treatment seeking or a recent history of treatment for cannabis abuse or dependence
• Endorses a current commitment to stop using cannabis
• Clinically significant physical abnormalities as indicated by physical exam, hematological assessment, bilirubin concentration or urinalysis
• History of renal impairment, renal stones, seizures, or unstable hypertension
• Underweight (i.e., less than the 5th percentile) or overweight (equal to or greater than the 95th percentile), as determined by the Body Mass Index
• Positive urine toxicology screen for narcotics, amphetamines, or sedative hypnotics or self-reported drug use, other than cannabis, alcohol or nicotine, in the past 30 days
• Pregnant, nursing, or refusal to use reliable barrier method of birth control (e.g., condom), if female
• Took a psychotropic medication in the past 30 days
• Taking medications with a potential effect on cannabis use or a carbonic anhydrase inhibitor
• Suicidal
• A current DSM-IV-TR Axis I diagnosis other than attention- deficit/hyperactivity disorder or a disruptive behavior disorder
• A current substance use disorder other than a cannabis, alcohol, and nicotine use disorders
• Significant alcohol withdrawal symptoms
• Known sensitivity to topiramate

Data were collected during the 6-week medication (or placebo pill) period.

We followed the same definition as clinicaltrials.gov.