Researchers from Brown University reported that combining topiramate with psychological counseling reduced marijuana use among young smokers significantly more than counseling alone. However, many study participants could not tolerate the drug’s adverse effects. Findings from the study are published in Addiction Biology.
Currently, there is no approved treatment for cannabis dependence and misuse. Topiramate, an antiepileptic, was studied previously as possible treatment for alcohol and nicotine dependence, and cocaine addiction.
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The randomized, controlled trial (n=66) was conducted to test whether topiramate could provide more benefits to MET. It recruited volunteers aged 15–24 who smoked at least twice a week but desired psychological and drug treatment to reduce marijuana use. Half of the study volunteers met the criteria for marijuana dependence or abuse. They were assigned to placebo or topiramate along with 50-minute MET sessions at Weeks 1, 3, and 5 of the 6-week study. Forty participants received topiramate doses that were titrated up from 25mg in Week 1 to 200mg by Week 5.
Study authors found that the drug provided a statistically significant benefit. Topiramate did not decrease the frequency of smoking significantly more than therapy alone, though study participants who received topiramate and MET used less marijuana each time than those who received counseling and a placebo. On average, topirate and MET subjects used about 0.2g less of cannabis after each week.
By the end of the study, 21 of the 40 participants who received the drug dropped out vs. 6 of the 26 participants who received placebo. Side effects were cited as the reason in two-thirds of patients who left after taking topiramate. Side effects included depression, anxiety, coordination and balance difficulties, weight loss, and unusual sensations.
Researchers call for a larger and longer clinical trial in the future. In addition to a study which can determine whether genetic markers or factors may prove useful in predicting who will have less difficulty with topiramate’s side effects.
For more information visit news.brown.edu.