Cannabis can provide significant short-term relief from symptoms associated with autism spectrum disorder (ASD) in adults, according to the results of a new study.
The research, published in the journal Scientific Reports, examined data from 111 self-identified autistic adults who used cannabis to manage their symptoms over a 74-month period. Participants tracked more than 5,900 cannabis use sessions through the Strainprint app, rating symptom severity before and after use.
Results showed that overall symptom severity ratings decreased by 73.09% from before to after cannabis use, with symptoms reduced rather than exacerbated in 98.33% of tracked sessions.
The study focused on four symptom clusters commonly associated with autism: sensitivity issues (including sensory overload and sound sensitivity), repetitive behaviours, mental control problems (such as difficulty concentrating and intrusive thoughts), and negative affect (anxiety and irritability).
Sensitivity symptoms showed a 68.09% reduction, repetitive behaviours decreased by 70.41%, mental control issues dropped by 68.59%, and negative affect symptoms were reduced by 75.78%.
The study, co-led by Dr Debra Karhson from the University of New Orleans, noted that higher doses predicted greater reductions in severity for repetitive behaviours, mental control, and negative affect symptoms.
The research also revealed that more severe symptoms before cannabis use were associated with greater reductions in severity afterwards, though significant differences existed across individuals in how much relief they experienced.
Whilst doses remained consistent over time, baseline severity ratings for repetitive behaviours and negative affect significantly increased as participants continued using cannabis, suggesting that regular use might intensify these symptoms in the long term.
“While acute use of cannabis may provide a temporary reprieve from repetitive behaviours and negative affect without the development of tolerance to these effects, regular cannabis use may intensify these symptom clusters in the long-term,” the researchers wrote.
The study participants, aged 19 to 70, used inhaled cannabis products with varying concentrations of THC and CBD. Interestingly, the specific cannabinoid concentrations did not significantly influence symptom changes, contrasting with the results of other clinical trials, which focus primarily on CBD-rich products.
Age emerged as a significant factor, with older adults reporting greater relief from sensitivity symptoms than younger participants.
The researchers acknowledged several limitations, including the lack of verification for ASD diagnoses, potential sampling bias towards those who tolerate cannabis well, and the absence of a placebo control group. The non-experimental nature means expectancy effects likely contributed to some symptom reductions.
Current pharmacological options for ASD remain limited. In the United States, only two medications, aripiprazole and risperidone, are FDA-approved for treating ASD, both targeting irritability rather than core symptoms.
In the UK, however, no medications are currently licensed specifically for the core difficulties associated with autism spectrum disorder. Whilst aripiprazole and risperidone have shown evidence of efficacy for managing autism-related irritability, both remain unlicensed in the UK for this indication but can be prescribed off-label.
The study authors emphasised that their findings warrant well-powered placebo-controlled trials examining various cannabinoids’ effects on ASD symptoms in adults.
“These findings indicate that people using cannabis to manage symptoms associated with ASD may experience short-term, but not long-term, reductions in their symptoms,” the researchers concluded.
