ADHD is a neurodevelopmental disorder that is characterised by loss of attention and impulsive behaviour. There is substantial overlap between ADHD, Anxiety, PTSD, OCD and other autism spectrum disorders and possibly also between the therapeutic potential of cannabinoids in the treatment of these disorders.
Stimulants, such as amphetamines, are often used to treat ADHD.
The behavioral effects of amphetamine depend on its ability to increase monoamine neurotransmission in brain regions such as the nucleus accumbens (NAC) and medial prefrontal cortex (mPFC).
In a rat study it was found that the therapeutic effect of amphetamins actually requires CB1 activation (Kleijn et al., 2012).
This opens the possibility that treatment of ADHD with cannabinoids may supplement or replace current amphetamine treatment.
ADHD is a heritable disorder.
A genetics study pointed out that ADHD is tightly linked to small variations/mutations (single nucleotide polymorphisms) in the CB1 gene (CNR1)(Lu et al., 2008).
Similar to OCD, there is a correlation between the occurrence of ADHD and the use of cannabis.
The prevailing view was that cannabis use may therefore precipitate ADHD, but an alternative view is emerging that people that are prone to develop psychiatric disorders like ADHD may suppress symptoms by self-medicating with cannabis (De Alwis et al., 2014; Bidwell et al., 2014; Loflin et al., 2014).
De Alwis, D., Agrawal, A., Reiersen, A.M., Constantino, J.N., Henders, A., Martin, N.G., and Lynskey, M.T. (2014). ADHD symptoms, autistic traits, and substance use and misuse in adult Australian twins. J. Stud. Alcohol Drugs 75, 211–221.
Bidwell, L.C., Henry, E.A., Willcutt, E.G., Kinnear, M.K., and Ito, T.A. (2014). Childhood and current ADHD symptom dimensions are associated with more severe cannabis outcomes in college students. Drug Alcohol Depend. 135, 88–94.
Kleijn, J., Wiskerke, J., Cremers, T.I.F.H., Schoffelmeer, A.N.M., Westerink, B.H.C., and Pattij, T. (2012). Effects of amphetamine on dopamine release in the rat nucleus accumbens shell region depend on cannabinoid CB1 receptor activation. Neurochem. Int. 60, 791–798.
Loflin, M., Earleywine, M., De Leo, J., and Hobkirk, A. (2014). Subtypes of attention deficit-hyperactivity disorder (ADHD) and cannabis use. Subst. Use Misuse 49, 427–434.
Lu, A.T., Ogdie, M.N., Järvelin, M.-R., Moilanen, I.K., Loo, S.K., McCracken, J.T., McGough, J.J., Yang, M.H., Peltonen, L., Nelson, S.F., et al. (2008). Association of the cannabinoid receptor gene (CNR1) with ADHD and post-traumatic stress disorder. Am. J. Med. Genet. Part B Neuropsychiatr. Genet. Off. Publ. Int. Soc. Psychiatr. Genet. 147B, 1488–1494.
In a meta-study of clinical trials, supplementation of food with omega-3 fatty acids (especially EPA) was found to slightly, but significantly reduce behavioural symptoms of ADHD (Bloch and Qawasmi, 2011). Omega-3, and particularly the ratio of Omega-6 to omega-3 fatty acids are high-level regulators of the endocannabinoid system.
Bloch, M.H., and Qawasmi, A. (2011). Omega-3 fatty acid supplementation for the treatment of children with attention-deficit/hyperactivity disorder symptomatology: systematic review and meta-analysis. J. Am. Acad. Child Adolesc. Psychiatry 50, 991–1000.