The War Within
Cannabis appears to have no impact on PTSD treatment outcomes in veterans
Phoebe Harkin | | Quick Read
There are differing opinions on cannabis for PTSD. Some theorize it may provide a new treatment approach, others suggest it may worsen symptomatology. But evidence for its use is building. In 2002, researchers proposed that endocannabinoids facilitate extinction of aversive memories through their selective inhibitory effects on local inhibitory networks in the amygdala (2). Now, researchers have built on that work with a study to determine if cannabis use impacts the success of evidence-based intensive outpatient PTSD treatment in a veteran population.
Study participants were veterans aged 18 to 85 years, with at least two PTSD Checklist scores and an official diagnosis of the condition. Data collected included mental health medications, type and number of evidence-based psychotherapy used, and presence of co-occurring behavioral health diagnoses. A cannabis use group was compared with a no-cannabis-use group, to seek statistically and clinically significant differences in variables pertaining to the relative number of treatment successes and failures.
Meagan Petersen, Mental Health Clinical Pharmacy Specialist, Battle Creek Veteran Affairs Medical Center, and Professor, Pharmacy Practice Department, Ferris State University, Michigan, USA, led the study. “Before I began the study, I thought [cannabis] would have negative impacts on treatment as cannabis use disorder (CUD) has been associated with worsening depression and increased suicidal ideation. Now, I think it depends whether someone has CUD versus someone who occasionally uses – with the latter possibly being beneficial.”
To decide what qualified a treatment as a success or failure, the team used The PTSD Checklist (3), which suggests a five-point difference indicates some level of response to a treatment that is not due to chance. “We used this because we wanted to be sensitive to a potential difference, if one truly existed,” explains Petersen. So, what did they find? The success rate was similar between the cannabis and no-cannabis-use groups, at 51.9 percent and 51.4 percent, respectively. “I think it shows marijuana is not as detrimental to PTSD treatment as we once thought, and lends evidence that its use will not slow or hinder PTSD treatment benefit,” says Petersen.
But the study was not without limitations; participants were mostly white (87.1 percent) and male (95 percent). Though Petersen imagines the findings would apply to a non-Caucasian population, she cautions against extrapolating this information until it has been confirmed with research. Still, the results offer some hope to a population who have already given so much.
- M Petersen et al., Ment Health Clinic, 11, 238 (2021). PMID: 34316419
- G Marsicano et al., Nature, 418, 530 (2002). PMID: 12152079
- F Weathers, “The PTSD Checklist (PCL): Reliability, Validity, and Diagnostic Utility. Paper presented at the Annual Convention of the International Society for Traumatic Stress Studies”, San Antonio, Texas, USA (1993).