Parkinson's patients reported significant improvements in falls, pain, depression, tremor, and sleep with medical cannabis | Research

The takeaway

In a survey of 47 Parkinson's patients using medical cannabis for an average of 19 months, the largest reported improvements were in falls, pain, depression, tremor, stiffness, and sleep, though side effects included confusion and hallucinations.

Read this if you want to know what Parkinson's patients report about their experience with medical cannabis.

Falls improvement r=0.89, but 17% reported confusion and 17% hallucinations

What the researchers found

Forty-seven Parkinson's patients (40 men, median Hoehn & Yahr stage III) who had used medical cannabis for at least 3 months reported their symptom changes via structured telephone interviews.

The largest effect sizes for improvement were: falls (r=0.89), pain relief (r=0.73), depression (r=0.64), tremor (r=0.64), muscle stiffness (r=0.62), and sleep (r=0.60). These are considered large effects by standard benchmarks.

However, adverse effects were notable: 34.9% of smokers reported cough, and 17% each reported confusion and hallucinations. Five patients (10.6%) stopped treatment due to adverse effects. Most patients (80.9%) used cannabis by smoking, at a mean daily dose of 0.9g.

Why it matters

Parkinson's disease involves multiple disabling symptoms beyond the hallmark tremor, including pain, depression, sleep disturbance, and falls. The large effect sizes reported across multiple symptom domains suggest that medical cannabis may address the broader symptom burden of PD, though the uncontrolled design and potential for placebo effects limit the conclusions.

The numbers in context

Effect sizes: falls r=0.89, pain r=0.73, depression r=0.64, tremor r=0.64, stiffness r=0.62, sleep r=0.60. Adverse effects: cough 34.9%, confusion 17%, hallucinations 17%. Treatment stopped: 10.6%. Mean daily dose: 0.9g. Mean treatment duration: 19.1 months.

How the study worked

Retrospective survey using structured telephone interviews with standardized subjective global impression of change measures. Conducted across two centers. Patients had to have been using medical cannabis for at least 3 months and be non-demented. This was not a controlled trial; there was no placebo group.

What this study cannot tell us

Uncontrolled retrospective survey with no placebo comparison. Self-reported improvements may reflect placebo effects, regression to the mean, or recall bias. The sample was predominantly male (85%). Most patients smoked cannabis, which has its own health risks. The cough rate highlights the unsuitability of smoking as a delivery method for patients with neurological disease.

How to read the evidence

Uncontrolled retrospective survey. Reports patient experience but cannot distinguish treatment effects from placebo or natural symptom fluctuation.

When this study was published

Published in 2017. Interest in cannabis for Parkinson's has grown, with several controlled trials now underway or completed.

The bigger picture

The high rate of confusion and hallucinations (17% each) is particularly concerning in Parkinson's disease, where these symptoms can also result from the disease itself and its standard medications. Any cannabis-based treatment for PD would need to navigate this challenge carefully, potentially using lower doses or non-psychoactive cannabinoids.

Questions still open

Would the benefits persist in a placebo-controlled trial? Could non-smoked delivery methods reduce adverse effects while maintaining benefits? Are the confusion and hallucinations from cannabis distinguishable from Parkinson's-related symptoms? Would CBD-dominant formulations offer benefits with fewer psychiatric side effects?

Common questions

Can cannabis treat Parkinson's disease?

This survey found that patients reported improvements in multiple Parkinson's symptoms, but without a control group, it cannot determine whether cannabis caused the improvements. Controlled trials are needed to establish whether these self-reported benefits are real and reproducible.

Why did some patients experience confusion and hallucinations?

Both confusion and hallucinations can be caused by THC and are also common symptoms of Parkinson's disease itself, especially at advanced stages. The combination of cannabis with Parkinson's medications that also affect dopamine may increase this risk.

Read the original research

Medical Cannabis in Parkinson Disease: Real-Life Patients' Experience.

Clinical neuropharmacology, 40(6), 268-272

View on PubMed ↗Publisher’s paper ↗

Citation

Balash, Yacov; Bar-Lev Schleider, Lihi; Korczyn, Amos D; Shabtai, Herzel; Knaani, Judith; Rosenberg, Alina; Baruch, Yehuda; Djaldetti, Ruth; Giladi, Nir; Gurevich, Tanya. (2017). Medical Cannabis in Parkinson Disease: Real-Life Patients' Experience.. Clinical neuropharmacology, 40(6), 268-272. https://doi.org/10.1097/WNF.0000000000000246