Studies to support the use of cannabis in clinical practice

Below you will find links to a total of 34 clinical trials in the following composition: 30 randomized controlled trials, three non-randomized trials and one uncontrolled trial. The randomized clinical trials were either parallel-group or cross-over, most using a placebo control group and only two using an active placebo group with diazepam. Most studies included more than one treatment arm, e.g. in herbal cannabis, different strains with different concentrations of THC or CBD and a combination of THC / CBD. Hemp products were used in most cases as an adjunct to current analgesic treatment. There was great heterogeneity between studies in terms of drugs, doses, routes of administration, frequency, comparators, and outcomes.

The most studied indication in the studies was neuropathic pain in patients with multiple sclerosis. In summary, the existing evidence shows that cannabis is effective for the neuropathic pain associated with this disease, especially when compared with placebo. The effects of cannabis on neuropathic pain in the context of other conditions such as HIV, diabetic pain, post-surgical pain, post-traumatic pain and peripheral neuropathic pain have also been evaluated in a minority of studies, also with promising effects of cannabis on pain relief.

Within meta analysis from 2018 compared 17 clinical trials of more than 3,100 patients with multiple sclerosis who were treated with medical cannabis. In the abstract, we read that treatment with cannabinoids led to effective subjective relief of spasticity compared to placebo. Regarding the objective effects on spasticity measured by the Modified Ashworth scale, no significant differences were observed. However, subjective effects were better than placebo both in the case of nabiximols (an oral spray with an extract of plant origin containing THC:CBD in a ratio of 1:1) and in the case of cannabis.

The discussion goes on to say that “when comparing the effectiveness of cannabinoids to other treatments for spasticity, such as baclofen or various intrathecal corticosteroids, on the modified Ashworth scale, baclofen reduced scores by an average of 0.58 and corticosteroids by 0.78.” Cannabinoids (nabiximols) reduced spasticity on the same scale by an average of 0.1 to 3.3. It is also necessary to take into account the risk of corticosteroids and baclofen.

Below you will find links to selected studies:

Systematic review and meta-analysis of studies looking at the effects of cannabinoids in palliative care, published in 2016, includes nine randomized open-label or crossover trials with more than 1,500 patients. In conclusion, it is stated that “Cannabinoids may lead to an increase in appetite in patients with HIV and the so-called wasting syndrome, although treatment with megestrol acetate has better results than treatment with cannabinoids.”

Clinical research with appropriate standards of evidence-based medicine is scarce, let’s mention one open prospective study from 2022. 18 patients were monitored as part of it, 3 of whom did not complete the study. For the remainder, after twelve weeks of cannabis treatment (80 percent of subjects smoked dried flowers), a significant 38 percent reduction in tic severity as measured on the Baseline Yale Global Tic Severity Scale (YGTSS) was found. Furthermore, there was a 20 percent reduction in the PUTS scale (Premonitory Urge for Tic Scale). In conclusion, the authors state that cannabis for medical use has good efficacy and is well tolerated by patients with Tourette syndrome. Interestingly, most of the patients preferred smoking to using the extract in oil in the form of drops.

In recent years, the anti-inflammatory properties of phytocannabinoids have attracted the interest of researchers and clinicians, as they represent a promising treatment option for autoimmune and inflammatory skin diseases that may be refractory to conventional therapy. It was performed by American dermatologists in October 2020 primary research of professional literature in this field, namely all articles on cannabis in dermatology published between 1965 and 2020. Review articles, studies using animal models, and non-dermatology and pharmacological studies were excluded. Of 248 non-duplicated studies, 26 articles were included. There were 13 articles related to the systemic use of cannabinoids and 14 with local use. It was found that “selective agonists of CB2 receptors are effective in the treatment of diffuse systemicsclerodermaand dermatomyositis. In addition, dronabinol has shown efficacy in trichotillomania. Furthermore, sublingually administered CBD and THC have been successful in treating pain associated with epidermolysis bullosa.” According to the authors, available evidence suggests that cannabinoids may be effective in treating a variety of inflammatory skin conditions.