Up to 8.2% of Americans and 9.2 of Canadians suffer from PTSD, and estimates of the global prevalence rate vary wildly, from 1.3% to 37.4% . Many sufferers of PTSD report significant relief from their symptoms when consuming cannabis, and recently there have been several shocking reports of U.S. veterans and other affected individuals given harsh custodial sentences as a result. Clearly, further work is needed to ensure that these individuals are able to medicate as needed.
Post-traumatic stress disorder (PTSD) is a severe psychiatric condition which can render sufferers incapable of enjoying a normal lifestyle. As the name suggests, the condition is a direct result of experiencing earlier trauma, and symptoms include flashbacks of the traumatic event, avoidance of associated triggers, anxiety, depression, anger and hyper vigilance.
Global Prevalence of PTSD
Up to 8.2% of Americans and 9.2 of Canadians suffer from PTSD, and estimates of the global prevalence rate vary wildly, from 1.3% to 37.4%. Many sufferers of PTSD report significant relief from their symptoms when consuming cannabis, and recently there have been several shocking reports of U.S. veterans and other affected individuals given harsh custodial sentences as a result. Clearly, further work is needed to ensure that these individuals are able to medicate as needed.
Not every individual that experiences a traumatic event will go on to develop PTSD. One study determined that 17% of Iraq veterans would go on to develop PTSD, generalised anxiety disorder or depression, another that around 25% of children exposed to trauma will go on to develop PTSD. Another concluded that monozygotic (identical) twins have a greater risk of developing PTSD after combat trauma if their twin also suffers from the disorder, pointing to a genetic predisposition.
PTSD and substance dependence
Sufferers of PTSD, in common with many other psychiatric disorders, are more likely to be dependent on substances such as alcohol, cannabis and cocaine. Therefore, whether cannabis can be truly seen as a treatment for PTSD remains in question, as affected individuals may seek solace in such substances whether or not they are truly an effective medication.
Although there has been significant research into substance use among those suffering from PTSD, studies relating to the effectiveness of cannabis as a treatment are relatively sparse. Up until relatively recently, the consensus among the medical community generally was that PTSD was a contributing factor in cannabis use disorders, and little investigation was undertaken into the brain mechanisms by which such disorders develop.
The role of the endocannabinoid system in PTSD
Understanding of the complexities of the endocannabinoid system has increased in recent years, and the role that it may have to play in regulating the symptoms of PTSD and similar disorders has come into focus. An article published in 2012 noted that stress-tolerant individuals exposed to acute stress in the form of a parabolic flight experiment experienced significantly-increased endocannabinoid (EC) concentration in the plasma, whereas non-stress-tolerant individuals experienced no increase.
However, these individuals were healthy, and not suffering from any chronic stress condition. PTSD (and other chronic stress) sufferers, on the other hand, showed consistently elevated levels of EC concentration compared with non-sufferers, even in ordinary, non-stressful situations. This implies that the EC system plays a definite role in the stress response, but the exact mechanism is still unclear.
Genetic phenotype of CB receptors could increase predisposition to PTSD
It was also noted that patients who had undergone cardiac surgery experienced more intense symptoms of PTSD post-surgery if they carried a single-nucleotide polymorphism (a variation affecting just one of the nucleotide bases, A, C, T or G) of the CB2 receptor gene.
An article published this year describes the role of the CB1 receptor in the experience and memory of stressful events: normal EC signalling through the receptor assists in extinction of fear, and impaired signalling is associated with a failure to eradicate memories of trauma, as well as chronic anxiety and depression (in animal subjects).
The article also noted that existing medications for PTSD have been implemented “opportunistically” when their benefits were discovered, and that such medications had usually been originally designed for other conditions. Often, such drugs are of limited effectiveness and may harbour serious side-effects.
THC and Nabilone as possible treatment options
The author concluded that while use of tetrahydrocannabinol (THC) could provide temporary cessation of symptoms, but that long-term use would lead to impairment of CB1 receptor signalling, causing an increase in the severity of anxiety, irritability and sleep disturbance in PTSD sufferes.
A study in 2009 investigated the effectiveness of nabilone, a synthetic form of THC, as an adjunctive treatment for PTSD. An adjunctive therapy is one that is prescribed in addition to a primary medication, in this case antidepressants and hypnotics. This study found that 72% of patients experienced cessation or reduction in nightmares, improvement in sleep time and quality, and a reduction of daytime flashbacks.
Although the results of this study are promising, the small sample size of just 47 individuals means that further research must be done to determine the effectiveness of nabilone. As interest in use of cannabinoids as treatment for PTSD is increasing so rapidly, we are likely to see the results of further research in the near future.
Furthermore, despite ongoing controversy surrounding the effectiveness of medical cannabis as a treatment for PTSD, the Medical Cannabis Advisory Board recently recommended keeping PTSD on the list of qualifiers allowing prospective cannabis users to take prescriptions.
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