Investigators noted the psychiatric adverse effects of treatment with medical cannabis, requiring patient monitoring after initiation.
Data from a real-life study of medical cannabis (MC) on adults with dystonia were presented at The International Parkinson and Movement Disorders (MDS) Society Virtual Congress 2021, September 17-22, with investigators concluding MC treatment seemed to improve dystonia symptoms, as well as related pain.
A total of 23 patients with a mean age of 52.7 years were interviewed for the small, retrospective pilot study, including patients with focal dystonia (n = 6), multifocal dystonia (n = 1), segmental dystonia (n = 5), generalized dystonia (n = 9), and hemidystonia (n = 2). For 10 patients, the etiology of dystonia was known, as 6 patients had Parkinson disease (PD) and 4 had monogenetic disease, DYT1 or DYT6.
A positive correlation was identified between percentage of product tetrahydrocannabinol (THC) and total THC daily dose and subjective improvement of dystonia, P = 0.034, and P = 0.012, respectively, reflecting that patients intaking a higher level of THC showed significant improvement when compared to those consuming lower doses.
Additionally, investigators, led by Saar Anis, MD, neurologist and movement disorders specialist, Movement Disorders Institute, neurology department, Sheba Tel-HaShomer Medical Center, Israel, evaluated the administration method of MC, with 43.5% of patients smoking, 47.8% consuming via sublingual cannabis oil extract, and 8.7% utilizing both methods. Patients who smoked MC had significantly higher improvement in dystonia symptoms, reporting up to 80% improvement, whereas those who use sublingual oil reported a 20% improvement.
“For me, the surprising result was that I saw a significant difference between compounds of medical cannabis, which are THC-rich, in comparison to cannabidiol (CBD)-rich, and we found that THC-rich products were much [more] beneficial in terms of dystonia and pain compared to CBD-rich compounds,” Anis told NeurologyLive. “This is pretty significant because in this field of dystonia…we don't know exactly which cannabis compounds are beneficial.”
When evaluating treatment effects using the 5-point Likert scale, comparing improvement to baseline, over 50% of patients reported improvements in quality of life when using MC, 30% were neutral, and less than 20% were unsatisfied. Patients were also surveyed n the effect of MC on related pain, with 85% reporting improvement, Anis said. Sleep improvements were reported by 16 of 23 patients (70%).
The most commonly reported adverse events (AEs) were dry mouth and fatigue (65%). Psychiatric side effects were reported by 6 patients (25%), notably anxiety in 3 patients (1 with hallucinations) and mood worsening in 4 patients (1 with suicidal thoughts). The importance of monitoring psychiatric symptoms such as anxiety and mood worsening was emphasized, particularly after the initiation of treatment. According to Anis, 1 patient discontinued treatment, and investigators adjusted cannabis doses for 5 patients to resolve side effects.
Patients had an average duration of cannabis use of 2.5 years (standard deviation [SD], 1.0) and an average dose of 22.6 grams/month (SD, 20.1). The average THC percentage in consumed cannabis products was 10.6% (SD, 6.6), and average CBD percentage was 8.0% (SD, 5.7).
Anis noted that the retrospective study was limited due to its small sample size, further calling attention to the heterogeneity of various distribution and dystonia etiology.
“We found that higher doses of THC also correlated with good benefit for dystonia, so I think for future research, [there are] a few things we have to consider,” Anis told NeurologyLive. “First of all, we need bigger numbers, and we need to clarify which compound is better for dystonia, and for hyperkinetic disorders, generally…I think that one future research field will be trying to identify the compounds of medical cannabis that will help the patients…and we need to make better randomized control studies to check that.”
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