Benefits and Harms of Plant-Based Cannabis for Posttraumatic Stress Disorder: A Systematic Review.

BACKGROUND: Cannabis is available from medical dispensaries for treating posttraumatic stress disorder (PTSD) in many states of the union, yet its efficacy in treating PTSD symptoms remains uncertain. PURPOSE: To identify ongoing studies and review existing evidence regarding the benefits and harms of plant-based cannabis preparations in treating PTSD in adults. DATA SOURCES: MEDLINE, the Cochrane Library, and other sources from database inception to March 2017. STUDY SELECTION: English-language systematic reviews, trials, and observational studies with a control group that reported PTSD symptoms and adverse effects of plant-based cannabis use in adults with PTSD. DATA EXTRACTION: Study data extracted by 1 investigator was checked by a second reviewer; 2 reviewers independently assessed study quality, and the investigator group graded the overall strength of evidence by using standard criteria. DATA SYNTHESIS: Two systematic reviews, 3 observational studies, and no randomized trials were found. The systematic reviews reported insufficient evidence to draw conclusions about benefits and harms. The observational studies found that compared with nonuse, cannabis did not reduce PTSD symptoms. Studies had medium and high risk of bias, and overall evidence was judged insufficient. Two randomized trials and 6 other studies examining outcomes of cannabis use in patients with PTSD are ongoing and are expected to be completed within 3 years. LIMITATION: Very scant evidence with medium to high risk of bias. CONCLUSION: Evidence is insufficient to draw conclusions about the benefits and harms of plant-based cannabis preparations in patients with PTSD, but several ongoing studies may soon provide important results. PRIMARY FUNDING SOURCE: U.S. Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Quality Enhancement Research Initiative. (PROSPERO: CRD42016033623).

The Effects of Cannabis Among Adults With Chronic Pain and an Overview of General Harms: A Systematic Review.

BACKGROUND: Cannabis is increasingly available for the treatment of chronic pain, yet its efficacy remains uncertain. PURPOSE: To review the benefits of plant-based cannabis preparations for treating chronic pain in adults and the harms of cannabis use in chronic pain and general adult populations. DATA SOURCES: MEDLINE, Cochrane Database of Systematic Reviews, and several other sources from database inception to March 2017. STUDY SELECTION: Intervention trials and observational studies, published in English, involving adults using plant-based cannabis preparations that reported pain, quality of life, or adverse effect outcomes. DATA EXTRACTION: Two investigators independently abstracted study characteristics and assessed study quality, and the investigator group graded the overall strength of evidence using standard criteria. DATA SYNTHESIS: From 27 chronic pain trials, there is low-strength evidence that cannabis alleviates neuropathic pain but insufficient evidence in other pain populations. According to 11 systematic reviews and 32 primary studies, harms in general population studies include increased risk for motor vehicle accidents, psychotic symptoms, and short-term cognitive impairment. Although adverse pulmonary effects were not seen in younger populations, evidence on most other long-term physical harms, in heavy or long-term cannabis users, or in older populations is insufficient. LIMITATION: Few methodologically rigorous trials; the cannabis formulations studied may not reflect commercially available products; and limited applicability to older, chronically ill populations and patients who use cannabis heavily. CONCLUSION: Limited evidence suggests that cannabis may alleviate neuropathic pain in some patients, but insufficient evidence exists for other types of chronic pain. Among general populations, limited evidence suggests that cannabis is associated with an increased risk for adverse mental health effects. PRIMARY FUNDING SOURCE: U.S. Department of Veterans Affairs. (PROSPERO: CRD42016033623).