Emily Ledger

In recent years, medical cannabis has been slowly emerging from the shadows and is increasingly seen as a legitimate treatment for a large number of ailments. There is growing evidence to suggest its potential in the management of several conditions from epilepsy to anxiety; but what about obsessive-compulsive disorder? What is obsessive-compulsive disorder? Obsessive-compulsive disorder – widely known by its abbreviation ‘OCD’ - is a chronic psychiatric disorder characterised by symptoms including compulsions and intrusive thoughts. Many people with OCD experience compulsive urges; for example, these may manifest as a frequent need to clean, check locks, or wash their hands. It is also common for people living with OCD to experience heightened anxiety and persistent fears (e.g., of things going wrong). The exact cause of OCD still isn’t fully understood; however, it is believed that genetics, brain abnormalities, and environmental factors may play a role in the development of the condition. Some reports suggest that OCD may be associated with alterations in brain function and in the levels of neurotransmitters such as serotonin, dopamine, and glutamate. OCD is typically diagnosed during a physical and psychiatric examination when obsessions and compulsions begin to interfere with daily life, take up at least one hour each day, or cause distress to the individual. Conventional treatment for OCD typically includes medications (often antidepressants) and therapies, such as cognitive behavioural therapies. Many patients may find these interventions helpful; however, they are not always effective at managing the condition and its symptoms. Furthermore, some medications used in the treatment of OCD may have undesirable side effects. Medical cannabis and OCD Cannabis has been used medicinally for thousands of years, and despite restrictions in many parts of the world, the use of the drug in the aid of both physical and mental conditions remains extremely high. Cannabis use is often higher among patient populations – a trend that can also be seen among people with OCD. According to a report by a large residential treatment facility for OCD in the US, around 30% of adults seeking intensive OCD treatment endorsed current or past cannabis use. There is evidence to suggest that patients with OCD may use cannabis as a means of self-medication; however, current clinical and real-world evidence to support this use is mixed. Some recent reports have implicated the endocannabinoid system (ECS) in the physiopathology of OCD. Furthermore, a small number of animal studies have found beneficial effects in OCD-like behaviour after the use of substances that stimulate the ECS. However, very few studies have assessed this relationship in humans. Is there any evidence? The most recent study in this area, published in 2020, analysed data from the app Strainprint® which “provides medical cannabis patients a means of tracking changes in symptoms as a function of different doses and strains of cannabis across time.” The study included 87 individuals self-identifying with OCD who tracked the severity of their symptoms (intrusions, compulsions, and/or anxiety) immediately before and after cannabis use. The data suggested that acute cannabis use – particularly with high-CBD strains – was associated with a reduction of OCD symptoms. Almost all cannabis sessions recorded by participants resulted in a self-reported improvement in symptoms. Overall, participants reported an average of 60% reduction in compulsions, 49% reduction in intrusive thoughts, and a 52% reduction in anxiety. While these results seem promising, it must be noted that participants self-identified as having OCD, meaning that some may not have received an official diagnosis for the condition. Furthermore, the lack of a placebo control group makes it difficult to accurately determine the significance of these findings. Nonetheless, the findings of this study build on existing evidence that may support the use of medical cannabis in the treatment of obsessive-compulsive disorder. This includes a trial, published in 2020, that assessed the effects of cannabinoid augmentation of exposure-based therapy. Participants were assigned to either treatment with synthetic THC analogue nabilone alone or a combination of nabilone and exposure-based therapy for four weeks. Treatment with nabilone alone was associated with very minor symptom change; however, combined treatment with nabilone and exposure-based therapy significantly improved the therapeutic effect of exposure-based therapy. A controlled trial, published in 2008, also described the effects of dronabinol (added to existing treatments), in two patients with treatment-resistant OCD. In one patient, initiation of combined treatment with clomipramine and dronabinol was associated with a 50% decrease in OCD symptoms. The second patient, who was diagnosed with schizophrenia and OCD and admitted to the hospital due to deterioration of psychotic and obsessive symptoms, also experienced significant improvements following the initiation of combined therapy with dronabinol, clomipramine, and clozapine. Could cannabis use make OCD symptoms worse? While there is a growing body of evidence to support the initiation of more studies in this area, some past findings also report some negative associations between cannabis use and OCD symptoms. According to a 2021 survey of adults with OCD who used cannabis, 29% reported using cannabis specifically to manage OCD symptoms. However, while most participants reported improved obsessions/compulsions, cannabis use was also associated with decreased odds of receiving evidence-based treatments. Furthermore, other studies, including a randomised, placebo-controlled trial of 12 adults found that smoked cannabis did not significantly differ from placebo in its acute effects on OCD symptoms and state anxiety was significantly lower immediately after placebo administration relative to both THC and CBD. There is clearly a need for more studies into the relationship between the endocannabinoid system and obsessive-compulsive disorder, as well as the effects of medical cannabis on related symptoms. Until this is achieved, it is hard to say whether cannabis could be a helpful option for those living with OCD – though current findings seem promising. However, despite the current lack of clinical evidence, it may be possible to receive a medical cannabis prescription for OCD in the UK from a private clinic. Take a look the leafie guide to medical cannabis in the UK to learn more