ADHD is one of the most common neurodevelopmental conditions, affecting about 8% of children under 12. The prevalence of persistent adult ADHD (with childhood onset) is estimated to be around 2.6% of the population and symptomatic adult ADHD (regardless of childhood onset) around 6.8% (Song et al., 2021 1). It is the most common psychiatric disorder in childhood with key symptoms of inattentiveness (difficulty concentrating), hyperactivity and impulsivity. It significantly impairs many aspects of life, commonly leading to educational underachievement, difficulties with employment and relationships and an increased risk of criminality. It also has significant correlations with a wide range of linked psychiatric disorders including mood disorders, anxiety disorders, substance misuse and self-harm (Sayal et al., 2018 2, Sobanski 2006 3 and Liu et al., 20194).
There is a certain amount of research evidence to suggest that medicinal cannabinoids may be helpful in treating adult ADHD (Fransisco et al., 20235). This systematic search of the wider evidence base included all publications up to 27th June 2022 with both experimental and observational studies. Of 39 studies, one employed a randomised and placebo-controlled design. Positive suggestions included outcomes suggestive that Cannabidiol (CBD) improved ADHD symptoms however, overall, the small sample sizes and limitations in objective measurements for cannabis exposure as well as mixed definitions mean there are limitations on being able to draw definite conclusions. Reports that cannabinoids help improve focus and hyperactivity in adults with ADHD (Mitchell et al., 2016 6) have relied on qualitative analysis of online forum discussions which, at best, leads to an anecdotal suggestion that people can find unlicenced, unregulated use of illegally derived cannabis helpful. A 2022 study (Stueber and Cuttler, 20227) found people diagnosed with ADHD reported that illegally derived cannabis use helped with their symptoms and medication side effects. However, self-reporting is subjective therefore not to be considered reliable. One of the more pertinent pieces of research is a randomised control trial looking at medicinal cannabinoids in ADHD (Cooper et al., 20178). This experimental study of Sativex spray in 30 adults with ADHD showed small but significant improvement in hyperactivity/impulsivity, inhibition and inattention. The study was suggestive that adults with ADHD may represent a subgroup of individuals who experience reduced symptoms without cognitive impairment following use of medicinal cannabinoids. While not definitive, this study does provide preliminary evidence to support the role of the endocannabinoids system in ADHD.
A small 2020 study of 112 adult medical cannabinoids patients with ADHD (Hergenrather et al., 20209) found that those who took a higher dose of CBD took fewer other ADHD medications. A 2020 scientific review (Khan et al., 202010) looked at the therapeutic application of CBD in mental health. This systematic search of case reports, case series, open label trials, non-randomised and randomised controlled trials (RCTs) resulted in 23 relevant studies whose quality of evidence was judged by levels of evidence related to quality and study design. Graded recommendations from Grade A (strong), Grade B (moderate), Grade C (weak) to Grade D (weakest) were applied. Grade B (moderate recommendation) supported the use of CBD for the treatment of ADHD with particular regard to comorbidities.
An analysis of clinical outcomes of medicinal cannabis therapy for ADHD (Ittiphakorn et al., 202311) analysed health related quality of life (HRQOL) and safety outcomes in ADHD patients treated with cannabis based medicinal products (CBMPs) and found significant improvements in general quality of life at 1, 3 and 6 months. The conclusion was an association between CBMP treatment and improvements in anxiety, sleep quality and general quality of life observed in patients with ADHD. Treatment was well tolerated at 12 months.
References
1 P. Song et al. 2021 “The prevalence of adult attention deficit hyperactivity disorder: A global systematic review and meta-analysis”. Journal of Global Health, 11.2 Kapil Sayal et al. 2018 “ADHD in children and young people: prevalence, care pathways and service provision”. Lancet Psychiatry: Feb;5(2): 175-186.
3 Esther Sobanski 2006 “Psychiatric comorbidity in adults with ADHD”. Eur Arch Psychiatry Clin Neursci. Sep:256 Suppl 1:i26-31.
4 Lu Liu 2019 “Is emotional lability distinct from ‘angry/irritable mood,’ ‘negative affect,’ or other subdimensions of oppositional defiance disorder in children with ADHD?”. J Atten Disord. Jun:23(8):859-868.
5 Anna Paula Fransisco et al. 2023 “Cannabis use in ADHD: A scoping review”. J Psychiatr Res.Jan:157:239-256.
6 John T Mitchell et al. 2016 “A qualitative analysis of online forum discussions on cannabis use and ADHD”. PLoS One. May 26;(5).
7 A Stueber & C Cuttler 2022 “Self-reported effects of cannabis on ADHD symptoms, ADHD medication side effects, and ADHD-related executive dysfunction”. J Atten Disord. 26(6):942-955.
8 R E Cooper et al. 2017 “Cannabinoids in attention-deficit/hyperactivity disorder: a randomised-controlled trial”. Eur Neuropsychopharmacol. 27(8): 795-808.
9 JY Hergenrather et al. 2020 “Cannabinoid and terpenoid doses are associated with adult ADHD status of medical cannabis patients”. Rambam Maimonides Med J. 11(1):e0001.
10 R Khan et al. 2020 “The therapeutic role of Cannabidiol in mental health: a systematic review”. J Cannabis Res.2:2.
11 Pim Ittiphakorn 2023 “UK Medical Cannabis Registry: an analysis of medicinal cannabis therapy for ADHD”. Neuropsychopharmacol Rep Dec.