Naltrexone as a Possible Treatment for Decreasing Cannabis Use

According to a SAMHSA survey, 19.8 million individuals or 7.5% of the US population were current (past month) users of marijuana in 2013. Among people age 18 to 25, current use reached 19.1%. Given the widespread consumption of marijuana, it becomes imperative to develop new therapeutic approaches to decrease its use. In a double-blind, placebo-controlled laboratory study, Dr. Haney and colleagues assessed the effects of 50 mg of naltrexone on the reinforcing, subjective, psychomotor, and cardiovascular effects of active and inactive cannabis. Daily cannabis users were treated with either naltrexone 50 mg daily (n=23) or placebo (n=28) for 16 days and were assessed for 4 to 6 weeks. Compared to the placebo group, the naltrexone group significantly used less cannabis and had less positive subjective effects from cannabis. Although naltrexone was associated with decreasing ratings of friendliness, food intake, and systolic blood pressure, and increasing spontaneous reports of stomach upset and headache, dropout rates were similar between groups. Based on their findings, the authors conclude that “naltrexone may reduce ongoing heavy cannabis use, relapse severity, or the likelihood that patients would return to pretreatment levels of heavy cannabis use in the event of a lapse.”