Numerous preclinical and clinical trials have shown that cannabidiol (CBD) holds therapeutic potential in the treatment of several neurological conditions. CBD is one of over 100 cannabinoids that are found in the cannabis sativa plant but it is non-psychoactive compared to the other major cannabinoid, Δ9- tetrahydrocannabinol or THC.
One neurological condition in particular that may benefit from cannabinoid treatment is a very common condition known as ADHD.
Attention Deficit/Hyperactivity Disorder or ADHD (the term ADD is sometimes used interchangeably) is a highly genetic, brain-based syndrome that is marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.
Although historically defined as a disorder of childhood, ADHD is increasingly recognized as a valid diagnosis in the adult population and is known to have an impact on “executive functioning skills”. These refer to brain operations such as attention, concentration, memory, motivation and effort, learning and mistakes, impulsivity, hyperactivity, organization, and social skills. Contributing factors that play a role in these challenges include chemical and structural differences in the brain as well as genetics.
According to a 2011-2012 study on the prevalence of ADHD in the U.S. conducted by the Centers for Disease Control and Prevention (CDC), approximately 11% of children 4-17 years of age (6.4 million) have at one point been diagnosed with ADHD. Meanwhile, the Attention Deficit Disorder Association estimates that approximately 5% of adults have ADHD. Together, that represents over 11,000,000 people in the US.
Prevalence in the U.S. is also known to be increasing as the percentage of children with an ADHD diagnosis increased significantly, from 7.8% in 2003 to 9.5% in 2007 and to 11.0% in 2011-12.
Unfortunately, higher prevalence of ADHD amongst the general population has not prompted new and better treatment options for those affected.
Because there is no cure for ADHD, treatments have mainly focused on reducing symptoms and improving functioning. Traditionally, this has meant medication, psychotherapy, education or training, or a combination of treatments.
In terms of medications, stimulants are the most common type of medication prescribed, followed by non-stimulant medications such as atypical antidepressants, and certain blood pressure medications.
However, medications often involve risks and side effects, especially when misused or taken in excess of the prescribed dose. For example, commonly prescribed stimulants can raise blood pressure and heart rate, and also increase anxiety. Antidepressants can sometimes cause a wide range of unpleasant side effects as well.
Over the last several years, the use of CBD to treat symptoms has been gaining favor amongst the ADHD community. Not only is CBD proven to be non-intoxicating, but numerous studies have found it to have an excellent safety profile and is extremely well-tolerated in adults and children. More importantly, its track record for dealing with neurological conditions is well known – making it an excellent candidate for further investigation as a potential therapeutic option for treating ADHD symptoms.
Cannabis and CBD versus ADHD: the studies
Although there are no clinical recommendations or systematic studies to date that directly support the use of cannabis to treat ADHD, it has been reported that adults with the condition often describe self-medicating with cannabis, with some reporting a preference for cannabis over ADHD medications. In fact, there is an increasingly popular perception that cannabis is therapeutic for the condition.
In a 2016 study published in the journal PLOS One, researchers conducted a comprehensive qualitative analysis of online forum discussions about the effects of cannabis use on ADHD. After sifting through 268 separate forum threads, the researchers found that most people believe that cannabis may be therapeutic for ADHD.
But aside from reports of self-medication, there is preclinical and clinical evidence that may support the theory that cannabis is a powerful ADHD treatment as well.
One 2012 study published in the Journal of Psychopharmacology investigated the effects of CBD on rats with drug-induced ADHD symptoms (using the drug Dizocilpine) including reduced social investigative behavior, reduced attention span, and hyperactivity.
Dizocilpine, also known as MK-801, is an uncompetitive antagonist (blocker) of the N-Methyl-D-aspartate receptor, a glutamate receptor. Glutamate is a powerful excitatory neurotransmitter that is responsible for sending signals between nerve cells, and under normal conditions it plays an important role in learning and memory. Using MK-801 to block the glutamate receptor in mice produces some of the hallmark ADHD symptoms.
Although pretreatment with CBD did not have an effect on drug-induced reductions in attention span, the team of researchers from Monash University in Melbourne, Australia, found that pretreating these rats with CBD not only normalized social investigative behavior, but also increased it beyond control levels. CBD also inhibited drug-induced hyperactivity as well. The results from this study suggest that CBD may be a potential therapeutic option to reverse some of the symptoms of ADHD.
Yet probably the most convincing study on CBD’s potential to treat ADHD is a small clinical trial that was conducted by a team of researchers from the Institute of Psychiatry Psychology and Neuroscience in the U.K.
The team conducted a randomized-controlled trial using the oromucosal spray Sativex (1:1 ratio of CBD and THC) for 30 adult patients with ADHD. The researchers found that Sativex improved hyperactivity/impulsivity, improved inattention, improved activity and cognitive performance, and improved emotional liability. They concluded that ADHD individuals may gain cognitive enhancement and enjoy a reduction of symptoms from the use of cannabinoids.
Their results were recently published in the journal European Neuropsychopharmacology in 2017.
Although ADHD is a multifaceted and complex disorder, emerging data most certainly warrants further investigation into cannabinoids as a potential treatment. The extensive sample size of positive anecdotal reports from patients purportedly benefiting from cannabis use in treating their ADHD symptoms, combined with promising preclinical data, offers a compelling argument for more research.
CBD in particular may be the phytocannabinoid that currently shows the most promise in the treatment of ADHD. Hopefully additional research will provide better insight into the causes of the disease while also helping to uncover the mechanisms by which CBD may be therapeutic for some patients.
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