Stopping Cannabis Use in Multiple Sclerosis May Improve Depression


Findings of the study provide a cautionary note in relation to cannabis use in people with MS, at least with respect to depression.

Anthony Feinstein, MBBCh, MPhil, PhD, FRCPC

Anthony Feinstein, MBBCh, MPhil, PhD, FRCPC

A study comparing the effects of cannabis continuation (CC) and cannabis withdrawal (CW) in patients with multiple sclerosis (MS) revealed that despite cannabis increasing mood levels, depression improved significantly in those off the drug. Findings of the study provide a cautionary note in relation to cannabis use in people with MS, at least with respect to depression.

After all the participants completed the Hospital Anxiety and Depression Scale (HADS), depression scores in those with MS who were using cannabis to manage their depression remained statistically unchanged in the CC group (n =20 ) but declined in the CW group (n = 19)(P = .006).

Researchers did not observe any group difference in the frequency of cannabis use (X2 = 0.31; P <.58) or in the amount smoked daily (CW: mean, 2.05 g [standard deviation (SD), 1.27]; CC: mean, 2.30 g [SD, 1.35]; t = 0.60; P = .56). Cannabis use for coping with depression was self-reported in 11 people with MS in the CC and 9 in the CW group.

In the CW group, HADS-D scores for the 9 people with MS who cited depression as their reason for using cannabis decreased significantly over the 28-day period (8.0 [SD, 2.92] vs 3.67 [SD, 2.6]; t = 3.75; P =.006). A similar decline was not seen in the CC group (n = 11; 8.27 [SD, 4.0] vs 7.73 [SD, 4.43]; t = 0.82; P = .432).

Over 28 days, the 11-nor-9-carboxy-Δ9-tetrahydro-cannabinol (THCCOOH)/creatinine ratio in the CW group declined to 0 (t = 4.505; P = .0001) whereas the CC group ratio remained unchanged (t = −0.379; P = .709).

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The study, conducted by Anthony Feinstein, MBBCh, MPhil, PhD, FRCPC, director of the neuropsychiatry program at Sunnybrook Health Sciences Centre and professor in the department of psychiatry at the University of Toronto, and colleagues, assessed whether symptoms of depression change when people with MS discontinue cannabis use.

In total, 40 people with MS who had smoked cannabis for an average of 7.66 (SD = 5.70) years, were assigned to the 2 groups. Both groups were followed for 28 days, by which point urinary levels of cannabinoid metabolites declined to almost 0.

Behavioral assessments at baseline and Day 28, including symptoms of anxiety and depression recorded using HADS and CW symptoms, were noted along with the Cannabis Withdrawal Scale (CWS). Researchers also recorded urinary levels of cannabinoid metabolites, THCCOOH and total cannabidiol at baseline and Day 28.

There were limitations to the study that should be noted. Almost 50% of cannabis users in both groups cited depression as their main reason for using the drug. The fact that symptoms of depression improved rather than worsened with cannabis abstinence therefore cautiously challenges this rationale. In addition to that, there are no clear cannabis guidelines for people with MS and the medical professionals engaged in their care. That being said, there are no ways to fully understand what sizable percentage of people with MS smoke, vape, or ingest cannabis regularly and who look to their doctors and therapists for advice in doing so.

Feinstein and colleagues noted that the findings of the study are more cautionary than anything else, adding that “a systematic review of cannabis efficacy and safety in people with MS from the Guideline Development Subcommittee of the American Academy of Neurology (AAN) provides no evidence for or against the use of cannabis in managing depression in people with MS.”


Feinstein A, Meza C, Stefan C, Staines WR. Discontinuing cannabis improves depression in people with multiple sclerosis: a short report. Mult Scler Demyelinating Disord. Published online June 26, 2020. doi: 10.1177/1352458520934070.

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