Evidence review of medical marijuana for neurological conditions | Research

The takeaway

Clinical evidence supported cannabinoid use for MS spasticity, refractory pain, and nausea, while lower-level evidence suggested potential for epilepsy, dystonia, tics, and tremors.

Read this if you want to understand the clinical evidence for medical cannabis in neurological conditions.

Four neurological indications with strong evidence; six more with emerging data

What the researchers found

This expert review assessed the evidence for cannabinoids in neurological diseases. High-quality clinical trial evidence supported the safety and efficacy of cannabinoids for four indications: spasticity in multiple sclerosis, pain not responding to opioids, glaucoma, and nausea/vomiting.

Lower-level clinical evidence indicated potential usefulness for dystonia, tics, tremors, epilepsy, migraine, and weight loss, though more research was needed. The review distinguished between THC (psychoactive) and CBD (neuroprotective in preclinical studies without psychoactive effects).

Common adverse effects included weakness, mood changes, and dizziness. Cardiovascular side effects and potential pulmonary effects from chronic smoking were noted. Fatalities were described as rare even with recreational use. Psychological dependence was a concern, but physical dependence was less well documented.

Why it matters

Neurological patients represent a significant proportion of medical cannabis users. This review from neurologists provided a clinical framework for understanding which conditions had adequate evidence and which remained speculative.

The numbers in context

Four indications had high-quality clinical evidence. Six additional conditions had lower-level evidence. CBD was highlighted as neuroprotective without psychoactive effects. Fatalities were rare even in recreational use.

How the study worked

Expert review of published clinical trials, preclinical studies, and safety data on cannabinoids for neurological indications.

What this study cannot tell us

The evidence base was limited by small sample sizes in many studies. Safety data were incomplete, especially for long-term use. The wide variety of cannabis preparations and routes of administration made comparing studies difficult.

How to read the evidence

Expert review synthesizing varied quality evidence, from high-quality RCTs to case reports and preclinical data.

When this study was published

Published in 2014, before CBD received FDA approval for epilepsy in 2018.

The bigger picture

This review was published at a pivotal moment: before CBD gained FDA approval for epilepsy (2018) but after sufficient preclinical evidence had accumulated to suggest neuroprotective potential. The authors positioned cannabinoids as a compassionate-use option for severe cases when standard treatments fail.

Questions still open

Which neurological conditions have gained stronger evidence for cannabinoid treatment since 2014? How does the route of administration (smoked, oral, spray) affect neurological outcomes? Can CBD-only preparations provide neurological benefits without the risks of THC?

Common questions

Which neurological conditions have the best evidence for cannabis treatment?

As of this 2014 review, the strongest evidence was for MS spasticity, pain not responding to opioids, nausea/vomiting, and glaucoma. Lower-level evidence existed for epilepsy, dystonia, tics, tremors, and migraine.

Is medical cannabis safe for neurological patients?

Common side effects included weakness, mood changes, and dizziness. Cardiovascular effects and potential lung effects from smoking were noted. The review described fatalities as rare even in recreational use, but physical dependence potential was not fully characterized.

Read the original research

Medical marijuana in neurology.

Expert review of neurotherapeutics, 14(12), 1453-65

View on PubMed ↗Publisher’s paper ↗

Citation

Benbadis, Selim R; Sanchez-Ramos, Juan; Bozorg, Ali; Giarratano, Melissa; Kalidas, Kavita; Katzin, Lara; Robertson, Derrick; Vu, Tuan; Smith, Amanda; Zesiewicz, Theresa. (2014). Medical marijuana in neurology.. Expert review of neurotherapeutics, 14(12), 1453-65. https://doi.org/10.1586/14737175.2014.985209