REVIEW OF: Olmos A et al, Addict Behav 2018;79:52–60

As medical and recreational marijuana become legalized in more states, more emphasis is being placed on treatment of those with cannabis use disorders. But with our clinics already at capacity, how can we find the most efficient way of providing therapy? Computerized interventions are already available for nicotine and alcohol use, but what about for cannabis?

This meta-analysis included 9 randomized control trials evaluating the efficacy of web-based treatments designed to reduce the frequency of cannabis use. The primary outcome was reduction in cannabis use, and the secondary outcome was reduction in other substance use. A total of 2,963 participants were included in the studies—1,724 in the intervention groups and 1,239 in the control groups. All the interventions were computer-based, and the control conditions varied from study to study—from no intervention to psychoeducation.

So, how did the computer-based interventions fare? Those who participated in the computerized interventions had a significant reduction in cannabis use when compared to the control groups (SMD: -0.19; 95% CI: -0.26 to -0.11), with no significant heterogeneity among the studies (I2 = 0%). Only 3 of the 9 trials collected data on the secondary outcome of reduction in other substance use, but there was again a significant reduction in those studies compared to the control condition (SMD: -0.27; 95% CI: -0.46 to -0.08), with low heterogeneity (I2 = 26%). Several sub-group analyses were performed, but the only significant result was in the number of sessions—interventions with ≥ 5 sessions performed better than those with < 5 sessions (SMD: -0.21; 95% CI -0.29 to -0.12).

CATR’s Take
With more people seeking treatment for substance use disorders, we need more options to give them effective care. This analysis shows that computerized interventions can work to help patients reduce cannabis use, along with other substance use. But it’s also important to note what the study doesn’t show: There was no comparison to a live therapist intervention. Sessions with an in-person therapist are still recommended, but when that’s not available, offering a computer-based intervention may be a good option.