Therapeutic Benefit of Smoked Cannabis in Randomized Placebo-Controlled Studies.
Level 1 - systematic review of randomized trials
Systematic review of randomized placebo-controlled trials
PubMed 29178487 · doi:10.1002/phar.2064
What was done
A literature review was conducted to identify randomized placebo-controlled trials evaluating the therapeutic efficacy of smoked cannabis on disease-specific primary endpoints. Open-label trials and non-smoked delivery methods were excluded. A total of 7 randomized controlled trials met the inclusion criteria and were synthesized.
What was found
The abstract provides no numerical data, confidence intervals, or sample sizes. Smoked cannabis did not outperform placebo for experimentally evoked pain or the timed walk test. Smoked cannabis lowered intraocular pressure, but the effect lasted less than 4 hours. Smoked cannabis, including at lower tetrahydrocannabinol concentrations, consistently increased total daily caloric intake and the number of eating occasions. Neither of the two trials assessing quality of life as a secondary endpoint found a statistically significant benefit.
Why it matters
Despite the prevalence of smoked marijuana use for medical conditions, high-quality placebo-controlled evidence demonstrates limited therapeutic efficacy, primarily restricted to appetite stimulation and a transient reduction in intraocular pressure.
Limits
Only 7 studies met inclusion criteria, reflecting a small overall evidence base. Pain was evaluated via experimentally evoked models rather than chronic clinical pain populations. The abstract omits total participant numbers, dose details, and exact statistical values. The duration of intraocular pressure reduction (<4 hours) is clinically inadequate for managing chronic conditions.