Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common childhood neurodevelopmental disorders that also affects a significant portion (1-6%) of the adult population (Kolar et al., 2008). Various studies have reported a significant amount of patients that claim administration of cannabis/cannabinoids alleviates or mitigates their ADHD symptoms.
A new 2017 study in 30 patients showed encouraging results in the use of Sativex, a 1:1 CBD:THC ratio, whole plant cannabis based formulation, for the treatment of ADHD. However, patients with ADHD are also at a higher risk for concomitant drug abuse, a comorbidity prevalent in an overwhelming percentage of patients (Kelly et al., 2016). While stimulant medications like Adderall and Ritalin are mainstay treatments prescribed by physicians in the treatment of ADHD, patients “self medicating” with cannabis have widely reported an improvement in their symptoms, as per anecdotal reports found online (Mitchell et al., 2016).
With limited clinical data available on the efficacy of cannabinoids in ADHD treatment, the paradox of employing cannabis, the most commonly abused drug in the U.S. and Europe, to treat patients who have a high risk for drug abuse, is a complicated one. This review will examine available data on the efficacy of cannabinoids in the treatment of ADHD, as the currently available findings warrant further study and scrutiny into cannabinoids as a potential ADHD treatment.
ADHD is estimated to affect 5% of children and 3% of adults (Polanczyk et al, 2007). The condition is generally characterized by “developmentally inappropriate and impairing levels of attention, hyperactivity and impulsivity, commonly accompanied by emotional dysregulation, cognitive impairments and psychiatric combordities” (Cooper et al., 2017). A commonly occurring phenomenon observed in patients with ADHD is co-occurring substance abuse, perhaps as a means of “self medicating” (Bolea-Alamanñac et al., 2014; Loflin et al., 2014).
A comprehensive review of anecdotal reports in online forums reveal that several patients with ADHD self report cannabis use and many consequently report alleviation of related ADHD symptomology (Mitchell et al., 2016). A new 2017 study indeed demonstrates the efficacy of an oral mucosal cannabinoid drug, Sativex, in a small sample of 30 adults diagnosed with ADHD (Cooper et al., 2017). Collectively, these findings begin to define a complex relationship between cannabis use and patients with ADHD, as well as its implications on cannabis/cannabinoids as a potential treatment for patients with this disorder. This article will examine the data from this study while also exploring other relevant and available data surrounding the potential use of cannabis in the treatment of ADHD.
Cannabis and cannabinoid therapy is increasingly being investigated and used in the treatment of a wide variety of pathologies with varying levels of success. While the efficacy of cannabis has been better studied and documented in the treatment of conditions such as epilepsy and glaucoma (Rosenberg et al., 2016; Tomida et al., 2004), other areas of cannabis research and medicine are still in its infancy and offer limited data.
One conditioning gaining popularity as a viable candidate for cannabinoid therapy is Attention Deficit Hyperactivity Disorder (ADHD). A new 2017 study performed by Cooper and colleagues piloted a randomized, placebo-controlled study involving the administration of Sativex, a whole plant cannabinoid medication, to 20 adults diagnosed with ADHD (Cooper et al., 2017). While the results of this study suggest the benefits of cannabis in the treatment of ADHD may be largely subjective, emerging data seems to suggest that the endocannabinoid system may be implicated in the pathophysiology of ADHD and should therefore be further investigated.
The mechanism for cannabinoids in the pathology of ADHD is still largely unknown, however, it is thought to be related to enhanced dopaminergic transmission (Cooper et al., 2017). This enhanced dopamine activity is the reason stimulants are considered the “gold standard” for pharmacotreatment of ADHD (Punja et al., 2016). Physicians, however, are sometimes reluctant to prescribe such psychotropic drugs to a population of patients commonly presenting with a comorbidity for substance abuse.
The same reluctance may be a factor in using cannabis, a widely abused drug, in the treatment of ADHD as well. However, this author argues that the side effect profile of cannabis may be better tolerated than that of stimulants. Insomnia is one of the most commonly reported side effects of stimulant medication and can have significantly detrimental effects on the patient, especially in children (Punja et al., 2016).
A 12-year comprehensive review showed a steep rise in stimulant medications (0.6% in 1987 to 2.7% in 1997) prescribed to children over time for the treatment of ADHD (Zuvekas & Vitiello, 2012). The use of these powerful psychotropic meds in children has begun to spur some controversy. A similar concern presents itself when considering cannabis treatment for ADHD in pediatric patients. More research is beginning to emerge on the role of cannabis in the developing brain and the results warrant further investigation into cannabis therapy in pediatric patients.
In trying to understand the role of cannabis use in the developing brain, it is critical to explore the documented neurocognitive effects of cannabis in children and adolescents. Recent attention has been brought to remarkably dramatic case reports of children with debilitating illnesses failing to respond to traditional medicine and for whom cannabis is the only solution. As such, there are an increasing number of pediatric and adolescent patients being added to the medical cannabis registry, particularly for conditions such as epilepsy (Handland et al., 2016).
However, early cannabis use in adolescents has also showed to negatively affect white matter in the brain by modulating axonal fiber connectivity, which are essentially the connective fibers that join brain cells called axons, which send electrical signals and messages around the brain (Zalesky et al., 2012). Heavy cannabis use in adolescents has also been proven to show negative brain related developments as well (Jacobus & Tapert, 2014).
When considering the architectural impact of ADHD in the brain however, a 2016 study by Kelly and colleagues that followed 75 adults over 7-9.9 years, demonstrated cannabis use “does not exacerbate ADHD related alterations” to the brain (Kelly et al., 2016). These findings continue to paint a sophisticated and complex picture in regards to cannabis and cannabinoid treatments for the treatment of ADHDH, especially in children.
The use of cannabis in the treatment of Attention Deficit Hyperactivity Disorder, a condition with a multifaceted, complex pathology that is compounded by the comorbidity of substance abuse, is complicated to say the least. However, emerging data most certainly warrants further investigation into cannabinoids as a potential treatment.
Additional research may provide better insight into the etiology and neuropharmacology of the disease while also helping elucidate the mechanisms by which cannabis may be therapeutic for some patients. The extensive sample size of positive anecdotal reports from patients purportedly benefiting from cannabis use in treating their ADHD symptoms, combined with the promising clinical data presented, such as the data from Cooper’s new study, offers a compelling argument for further investigation into cannabinoid treatment for ADHD. Whether the majority of symptom alleviation and benefits cannabis users with ADHD report can be scientifically verified in larger sample sizes, or if such effects are more subjective and solely present in the minds of the users still remains to be seen.
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