Cannabis for the treatment of PTSD: A review of the literature

Cannabis use is strongly associated with the comorbid presentation of post-traumatic stress disorder (PTSD) symptoms and diagnosis, although its role in the treatment of PTSD is not clear. In this article, we review studies that have examined the association between cannabis use and trauma as well as studies that evaluated the effect of cannabinoids on its symptoms.

What is PTSD?

Post-traumatic stress disorder (PTSD) is a condition that affects people who have experienced a traumatic event, like abuse or bullying. It causes flashbacks, nightmares and anxiety that can last for years. PTSD is estimated to affect 1 in 10 people in the UK, but many more are going undiagnosed due to a lack of understanding about what it is and how common it is.

How do you get post-traumatic stress disorder?

After a traumatic event, PTSD symptoms can begin right away, or they may not start until months or years later. If you have PTSD, it means that your brain has registered the experience as dangerous, and it has learned to react to future similar events with fear, anxiety and other negative emotions as a result of this past trauma.

If someone was involved in a car accident when they were young and were seriously injured, they may find it impossible to drive a car themselves. They may even have severe anxiety being a passenger or do what they can to avoid certain roads or routes. However, avoiding these situations can reinforce the belief that driving or taking a certain route is dangerous, and this thought pattern can maintain their fear response.

An overview of literature

Cannabis use has been associated with the presence of PTSD symptoms. A study published in 2014 found that cannabis users were more likely than non-users to report experiencing flashbacks and nightmares related to traumatic events (Buckner et al., 2014).

However, another study conducted by researchers at Boston University School of Medicine concluded that veterans who used marijuana had lower levels of anxiety and depression. This same study also found that individuals who consumed cannabis daily had lower scores on a scale measuring PTSD symptoms in comparison to those who did not consume any marijuana products at all (Rosenfeld, Sloman & Cohen-Kadosh et al., 2016).

The problems with this literature

The literature on cannabis and PTSD is still in its infancy. Most studies are conducted on small samples, and most do not consider other variables that may influence the relationship between cannabis use and PTSD symptoms, such as age, background, race and gender. It’s well known that PTSD is usually caused by a stressful or traumatic experience, which can also lead to the onset of other mental health issues, such as personality disorders and depression. These, in turn, can affect the results of drug use for treating distressing symptoms. Thankfully, the majority of studies did focus on medical use rather than recreational use.

Another problem was that several articles pointed to the lack of evidence for establishing a link between PTSD diagnosis and cannabis use. For example, one study shows no association, as do many others. Similarly, in population-based studies, cannabis use was more common in males than females with a diagnosis of PTSD, so the risk of bias is moderate-to-high in most studies.