Systematic review finds cannabinoids may help PTSD symptoms, especially sleep and nightmares, but evidence is low quality | Research

The takeaway

A systematic review of 10 studies found cannabinoids may reduce PTSD symptoms, particularly sleep disturbances and nightmares, but all studies had medium to high risk of bias and only one was a controlled trial.

Veterans and others with PTSD, trauma-focused clinicians, and military health researchers.

10 studies, all low quality; sleep/nightmares most consistently improved

What the researchers found

Every study had medium to high risk of bias and was of low quality. Within these limitations, cannabinoids appeared to decrease global PTSD symptoms, with the most consistent benefits for sleep disturbances and nightmares.

Why it matters

PTSD is a debilitating condition with limited treatment options, and many patients are already self-medicating with cannabis. This review quantifies how little rigorous evidence exists to guide this practice.

The numbers in context

10 studies included. Only 1 was a randomized controlled trial. All had medium to high risk of bias. Sleep and nightmare improvements were the most consistent findings.

How the study worked

Systematic review including all studies through December 2018 where patients had diagnosed PTSD and used cannabinoids to reduce symptoms. Only one study was an RCT; the rest were observational, retrospective, or case reports.

What this study cannot tell us

Nearly all evidence is observational or case-based. The single RCT was a small pilot study. Heterogeneous cannabinoid products and dosing across studies prevent meaningful comparison.

How to read the evidence

Preliminary: systematic review finding only low-quality evidence across 10 studies.

When this study was published

Published in 2020 in Journal of Dual Diagnosis.

The bigger picture

The gap between patient interest in cannabis for PTSD and the quality of available evidence highlights an urgent need for well-designed clinical trials, especially given the large veteran population using cannabis for PTSD.

Questions still open

Would large-scale RCTs confirm the sleep and nightmare benefits? Which cannabinoid (THC, CBD, or combination) is most appropriate for PTSD? Are there PTSD subtypes that respond better to cannabinoids?

Common questions

Can cannabis treat PTSD?

The evidence suggests it may help, particularly with sleep problems and nightmares, but the quality of research is too low to make clinical recommendations. All 10 studies had significant limitations.

Why is the evidence so weak?

Cannabis remains federally restricted in many countries, making clinical trials difficult. Most evidence comes from observational studies or case reports rather than the gold-standard randomized controlled trials needed for strong conclusions.

Read the original research

The Effectiveness of Cannabinoids in the Treatment of Posttraumatic Stress Disorder (PTSD): A Systematic Review.

Journal of dual diagnosis, 16(1), 120-139

View on PubMed ↗Publisher’s paper ↗

Citation

Hindocha, C; Cousijn, J; Rall, M; Bloomfield, M A P. (2020). The Effectiveness of Cannabinoids in the Treatment of Posttraumatic Stress Disorder (PTSD): A Systematic Review.. Journal of dual diagnosis, 16(1), 120-139. https://doi.org/10.1080/15504263.2019.1652380