Autism Spectrum Disorder (ASD) is a neurological and developmental disorder that is largely characterised by differences in social communication and interaction as well as the presence of restricted, repetitive behaviours and/or interests. ASD is a relatively common disorder that is thought to affect 1 in 132 people globally. The symptoms of ASD typically appear within the first two years of an individual’s life; however, many people are also diagnosed later in life.
People with ASD are more likely to be affected by comorbid symptoms, such as destructiveness, aggression, and hyperactivity – many of which persist into adulthood. ASD is also associated with an increased incidence of self-injury, psychiatric conditions, physical comorbidities, and sleep disturbance, all of which may be associated with reduced quality of life for both adult and paediatric patients.
Current Management Approaches to ASD
The broad range of symptoms associated with ASD means that there is no single best treatment approach, if one is needed at all. Instead, a combination of treatments, including psychological approaches and medications is usually advised. This can include medications such as monoamine reuptake inhibitors for the treatment of comorbid psychiatric illnesses. Atypical neuroleptics for the management of irritability and aggression may also be considered, although they are often poorly tolerated due to their associated side effects. There is, therefore, an unmet clinical need for the management of core symptoms of ASD, other associated symptoms, and comorbid diagnoses.
Medical Cannabis and ASD
In recent years, there has been an uptake in research focusing on the role of the endocannabinoid system in the pathophysiology of ASD. Due to this system’s implication in the regulation of anxiety, mood, motor coordination, and social behaviour, it is theorised that it may be promising for further research into how it may impact the non-core symptoms individuals with ASD might experience. Furthermore, children with ASD have been found to have lower circulating levels of anandamide – an endocannabinoid that acts as an endogenous ligand of CB1 receptors.
In the UK, cannabis-based medical products (CBMPs) may be considered for the management of ASD-associated symptoms, such as those listed above, if conventional treatments have failed to achieve satisfactory results or are not well tolerated. Nonetheless, there is a paucity of clinical evidence of the efficacy and safety of CBMPs in this setting. In order to address this, the UK Medical Cannabis Registry was established to record real-world outcomes of medical cannabis treatment for various conditions. A recent study aimed to assess the quality-of-life outcomes and adverse event incidence of patients prescribed CBMPs for ASD who were enrolled on the UK Medical Cannabis Registry.
Methods
The UK Medical Cannabis Registry has recruited patients via Sapphire Medical Clinic since 2019. The primary outcomes for assessment in this study were changes in the Generalised Anxiety Disorder Scale (GAD-7), 5-level version of the EQ-5D index value (a measure of health-related quality of life) and the single-item Sleep Quality Scale (SQS) from baseline to 1, 3, and 6 months. The Patient Global Impression of Change (PGIC) – a numerical scale where patients self-report changes in activity limitations, symptoms, emotions, and overall quality of life since starting treatment – was also reported at 1, 3 and 6 months.
Secondary outcome measures were the incidence of adverse events. These were self-reported by patients when completing patient-reported outcome measures (PROMs) or completed by clinicians during routine follow-up.
Results of the Study
A total of 74 patients with a mean age of 32.7 were included in the analysis. The completion of PROMs varied at 1 month (n = 60; 81.1%), 3 months (n = 49; 66.2%), and 6 months (n = 31; 41.9%). The majority of patients (67.6%) were regular cannabis users at baseline, prior to the initiation of formal medical cannabis treatment. Thirty-six (48.6%) participants were prescribed dried cannabis flower only, 16 (21.6%) were prescribed oral/sublingual preparations, and 22 (29.7%) were prescribed both CBMPs. The median prescribed CBD dose per day was 10.0 mg, while the median Δ9-THC dose was 112.5 mg per day.
Patient-Reported Outcome Measures
The studied PROMs showed improvements from baseline in general health-related quality of life, sleep, and anxiety in patients with ASD. For quality of life and sleep, these improvements were observed at 1, 3, and 6 months. Improvements in quality of life are supported by previous evaluations of participants in the UK Medical Cannabis Registry. However, this is the first study to report these findings in an adult ASD population.
Whilst sleep improved in this population, the effect of CBMPs on sleep is disputed. Furthermore, insomnia was the most commonly reported adverse event in this patient sample, indicating that CBMPs may have a negative impact on sleep in some patients.
Reductions in the severity of anxiety were observed at 1-month and 3-month follow-ups, but no change was reported at 6 months. While there was a general trend towards improved generalised anxiety symptoms at 6 months, a reduced sample size may have meant that this improvement was not significant. Nonetheless, previous evaluations of children and adults with ASD have similarly found associated improvements in anxiety outcomes.
Co-administered Medications and Adverse Events
The most commonly co-administered class of medications were antidepressants (n = 45; 60.8%), antiepileptics (n = 7; 9.5%), benzodiazepines (n = 12; 16.2%), neuroleptics (n = 12; 16.2%) and stimulants (n = 6; 8.1%). The researchers observed a reduction in co-administered medication from baseline. In all, 33.3% of participants stopped taking benzodiazepines and 25% of participants discontinued neuroleptics.
Adverse events were reported by 18.9% of participants, with a total incidence of 243.2%. Most adverse events were mild (78.4%) or moderate (109.5%).
Conclusions
This study is the first to assess the clinical outcomes of adults with ASD enrolled in the UK Medical Cannabis Registry. The patient sample demonstrated and reported improvements in general health-related quality of life, and sleep- and anxiety-specific outcomes. Whilst the results show promise, the authors of this study acknowledge the need for “further evaluation within the context of randomised controlled trials”.
