Adults with ADHD describe self-medicating with cannabis, with some reporting a preference for cannabis over ADHD medications.

The experimental medicine in ADHD-cannabinoids study was a pilot randomised placebo-controlled experimental study of a cannabinoid medication, Sativex oromucosal spray, in 30 adults with ADHD.

The primary outcome was cognitive performance and activity level using QbTest. Secondary outcomes included ADHD and emotional lability (EL) symptoms.

Thirty participants were randomly assigned to the active (n = 15) or placebo (n = 15) group. For the primary outcome, no significant difference was found in the ITT analysis although the overall pattern of scores was such that the active group usually had scores that were better than the placebo group (Est = -0.17, 95%CI-0.40 to 0.07, P = 0.16, n = 15/11 active/placebo). For secondary outcomes, Sativex was associated with non-significant improvements in hyperactivity/impulsivity (P = 0.03), a cognitive measure of inhibition (P = 0.05), inattention (P = 0.10) and emotional lability. Per-protocol effects were higher.

Results did not meet significance following adjustment for multiple testing. One serious (muscular seizures/spasms) and three mild adverse events occurred in the active group and one serious (cardiovascular problems) adverse event in the placebo group. Adults with ADHD may represent a subgroup of individuals who experience a reduction of symptoms and no cognitive impairments following cannabinoid use. This provides some preliminary evidence in support of the self-medication theory of cannabis use in ADHD. A larger trial is warranted.

Kings College London research support account for Asherson received honoraria for consultancy to Shire, Eli-Lilly and Novartis educational/research awards from Shire, Lilly, Novartis, Vifor Pharma, GW Pharma and QbTech speaker at sponsored events for Shire, Lilly and Novartis.