Stephanie Yarnell, MD, PhD
Prim Care Companion CNS Diord 2015;17(3):doi:10.4088/PCC.15r01786
By some collective lists, Posttraumatic Stress Disorder (PTSD) is an approved medical condition for the use of medical marijuana in more than half of the states where use is allowed. There is very little data in humans about efficacy for this indication. Much of the data is anecdotal and related to neurobiological theory of its mechanism of action. This paper reviews the existing information available before publication.
Many studies have shown a relationship of people with PTSD tend to use marijuana. However, it is unclear if the marijuana use aids in the coping of PTSD or worsens the symptoms of PTSD. In these studies, marijuana is said to help with the intrusions of the flashbacks associated with PTSD, may help with sleep issues, and provide relief from anxiety. On the other hand, it has been reported that while marijuana may initially help with sleep it may also interfere with long-term sleep patterns. In addition, problematic use and dependence on marijuana can lead to more anxiety and depressive symptoms. Problematic use and dependence is not defined. One author describes it as a cycle: PTSD predisposes someone to use marijuana to cope, withdrawal of the marijuana leads to greater PTSD symptoms, resulting in higher craving for marijuana, and then ultimately greater use of marijuana and increased negative effects.
The psychoactive effects of marijuana are thought to be a result of the compound THC and its interaction with cannabinoid receptor 1 (CB1). CB1 receptors are found in areas of the brain involved in memory formation, motor coordination, and emotional centers. This correlates well with seeing the effects of THC. For example, pain sensation, appetite, pleasure, concentration, and motor function. It is these reasons that the proposed benefit in PTSD is seen as providing calming effects to those areas that are hyper stimulated.
A discussion of short-term memory loss by marijuana is proposed to be a benefit in the patient with PTSD. Based on animal models, they were able to dissociate negative associations faster while exposed to THC. This association hasn’t been studied or confirmed in humans at this time.
Some purport that the use of marijuana in PTSD is just a “numbing” approach to treatment and no amount of drugs or medication will ultimately heal the pain of PTSD. While there is some evidence to support the use of marijuana in patients with PTSD, further research needs to be completed to elucidate the optimal dose, frequency, and long-term effects.