Do cannabis-based medicinal extracts have general or specific effects on symptoms in multiple sclerosis? A double-blind, randomized, placebo-controlled study on 160 patients

Multiple sclerosis is associated with muscle stiffness, spasms, pain, and tremor. Much anecdotal evidence suggests that cannabinoids could help these symptoms. Our aim was to test the notion that cannabinoids have a beneficial effect on spasticity and other symptoms related to multiple sclerosis. We did a randomised, placebo-controlled trial, to which we enrolled 667 patients with stable multiple sclerosis and muscle spasticity. 630 participants were treated at 33 UK centres with oral cannabis extract (n=211), Delta9-tetrahydrocannabinol (Delta9-THC; n=206), or placebo (n=213). Trial duration was 15 weeks. Our primary outcome measure was change in overall spasticity scores, using the Ashworth scale. Analysis was by intention to treat. 611 of 630 patients were followed up for the primary endpoint. We noted no treatment effect of cannabinoids on the primary outcome (p=0.40). The estimated difference in mean reduction in total Ashworth score for participants taking cannabis extract compared with placebo was 0.32 (95% CI -1.04 to 1.67), and for those taking Delta9-THC versus placebo it was 0.94 (-0.44 to 2.31). There was evidence of a treatment effect on patient-reported spasticity and pain (p=0.003), with improvement in spasticity reported in 61% (n=121, 95% CI 54.6-68.2), 60% (n=108, 52.5-66.8), and 46% (n=91, 39.0-52.9) of participants on cannabis extract, Delta9-THC, and placebo, respectively. Treatment with cannabinoids did not have a beneficial effect on spasticity when assessed with the Ashworth scale. However, though there was a degree of unmasking among the patients in the active treatment groups, objective improvement in mobility and patients' opinion of an improvement in pain suggest cannabinoids might be clinically useful.

To determine whether cannabis use in adolescence predisposes to higher rates of depression and anxiety in young adulthood. Seven wave cohort study over six years. 44 schools in the Australian state of Victoria. A statewide secondary school sample of 1601 students aged 14-15 followed for seven years. Interview measure of depression and anxiety (revised clinical interview schedule) at wave 7. Some 60% of participants had used cannabis by the age of 20; 7% were daily users at that point. Daily use in young women was associated with an over fivefold increase in the odds of reporting a state of depression and anxiety after adjustment for intercurrent use of other substances (odds ratio 5.6, 95% confidence interval 2.6 to 12). Weekly or more frequent cannabis use in teenagers predicted an approximately twofold increase in risk for later depression and anxiety (1.9, 1.1 to 3.3) after adjustment for potential baseline confounders. In contrast, depression and anxiety in teenagers predicted neither later weekly nor daily cannabis use. Frequent cannabis use in teenage girls predicts later depression and anxiety, with daily users carrying the highest risk. Given recent increasing levels of cannabis use, measures to reduce frequent and heavy recreational use seem warranted.