Two new systematic evidence reviews have found limited evidence for the efficacy of cannabis and plant-based cannabis products in chronic pain and post traumatic stress disorder (PTSD).
The first review looked at 27 chronic pain trials, finding low-strength evidence for the benefits of cannabis in neuropathic pain, but insufficient evidence in other pain populations. Evidence is also limited on its association with an increased risk for nonserious short-term adverse effects and potentially serious mental health adverse effects, such as psychosis, the authors said.
A second review also found insufficient evidence regarding the benefits and harms of plant-based cannabis preparations in patients with PTSD. Observational studies had shown that compared with nonuse, cannabis did not reduce PTSD symptoms, the authors said. In addition, the studies had medium and high risk of bias. The authors noted, however, that several ongoing studies may soon provide important results.
In an accompanying editorial , Dr Sachin Patel from Vanderbilt Psychiatric Hospital in the US said the reviews “highlight an alarming lack of high-quality data from which to draw firm conclusions about the efficacy of cannabis for these conditions, for which cannabis is both sanctioned and commonly used.”
The reviews and editorial are published in the Annals of Internal Medicine.