While cannabis may be the most common illicit drug in the word (2.8–5.8% of the world’s population are users), currently, there are no medications approved for the treatment of cannabis use disorder. In a study published in The Cochrane Library, researchers sought to assess the safety and efficacy of various pharmacotherapies in the treatment of cannabis dependence.

Using a literature search, the authors were able to identify 14 clinical trials that included 958 cannabis-dependent subjects (mostly male, average age: 33). Many medications were evaluated in these studies against placebo. These included selective serotonin reuptake inhibitors (SSRIs) (eg, fluoxetine, escitalopram), nefazodone, mirtazapine, venlafaxine, gabapentin, divalproex sodium, lithium, atomoxetine, buspirone, bupropion, and N-acetylcysteine.

Based on the available evidence the authors concluded the following:

  • Preparations containing tetrahydrocannabinol (THC): more effective than placebo in reducing withdrawal symptoms and cravings, however not associated with increased likelihood of abstinence or reduction in cannabis use
  • SSRIs: no significant effect on cannabis use
  • Nefazodone, mirtazapine, venlafaxine: no significant effect on withdrawal symptoms; abstinence varied (least likely with venlafaxine)
  • Anticonvulsants, mood stabilizers: gabapentin was associated with reducing cannabis withdrawal symptoms and reducing cannabis use; lithium affected some symptoms; divalproex did not reduce cannabis use
  • Bupropion: no effect on cannabis dependence; reduced withdrawal and craving a little
  • Buspirone: no effect on withdrawal symptoms or cannabis use
  • Atomoxetine: no effect on withdrawal symptoms or cannabis use
  • N-acetylcysteine: likelihood of negative urine tests for cannabis greater with N-acetylcysteine, however there was no significant difference in self-reported cannabis use; further exploration needed

The authors conclude that given most of the medications were only reviewed in one or two studies, and that the number of participants was small, more research would need to be done before a specific medication can be recommended for treating cannabis dependence. Gabapentin and N-acetylcysteine appear to be worth further investigation.