A University study released earlier this month suggests that an anti-epilepsy drug is effective in reducing the amount of marijuana smoked by young adults, but not necessarily the frequency of smoking.
Yet some scientists doubt the validity of the results, in part because half of the study’s medicated participants dropped out before the study concluded — some due to adverse side effects from the drug.
The study, published in the journal Addiction Biology, tested the effects of topiramate on heavy cannabis users ages 15 to 24. Topiramate was administered to 40 of the study participants, who also received three 50-minute sessions of motivational enhancement therapy, in which patients learn strategies to reduce their usage. The remaining 26 participants received only the therapy over the trial’s six weeks, in addition to a placebo pill.
The researchers used self-reports and urine toxicology to measure rates of marijuana use. Participants reported the amount of marijuana used on a particular day by weighing out oregano as an estimate, according to the study.
Sixty-six individuals began the six-week trial, but only 39 finished it — 52.5 percent of the topiramate group participants and 23.1 percent of the placebo group participants dropped out of the study.
Of the 21 dropouts from the topiramate group, 67 percent cited side effects as their reason for withdrawing. A multitude of side effects were reported by participants, including neurocognitive and gastrointestinal distress.
In future research, Miranda would like to investigate who tolerates topiramate best and possibly direct the treatment toward that group, he said. “I’m not sure what our next steps will be,” he added.
Miranda is currently investigating topiramate’s possible impact on alcohol abuse. The study is expected to conclude later this year.
In her lab, Haney has studied a few drugs that could have potential as treatment for marijuana dependence, such as tetrahydrocannabinol agonists. These medications behave somewhat like THC, so they can “reduce the withdrawal and decrease the desire to use marijuana” without the same risk of abuse.
Still, the Food and Drug Administration has yet to approve any medication for treating cannabis dependence, Miranda said.