Cannabis — whether marijuana itself or various products containing cannabinoids and/or THC, the main psychoactive compound in weed – have been touted as panaceas for everything from anxiety and sleep problems to epilepsy and cancer pain.
Nursing researcher Jennie Ryan, PhD , at Thomas Jefferson University, studies the effects of cannabis on symptoms of attention deficit hyperactivity disorder (ADHD). Current medical guidelines for ADHD include medications such as Adderall and cognitive behavioral therapy. As with most treatments, the benefits can be accompanied by downsides. "Parents are interested in cannabidiol, which does not contain THC," Dr. Ryan says. "But we don't have the science yet to back recommendations."
In a recent review paper , Dr. Ryan and her colleagues plumbed the scientific literature to compile evidence, which is generally suggestive of interactions between cannabis and ADHD. The researchers focused on how cannabis use affects ADHD symptoms. Furthermore, the human body produces its own cannabinoids – the endocannabinoid system – which led the researchers to wonder how might this endogenous system influence ADHD? They scrutinized clinical and preclinical findings, which together suggest that cannabis affects the endocannabinoid system in a variety of ways to affect attention, hyperactivity and anxiety.
"A relationship is there," Dr. Ryan says. However, the picture is complicated by the sheer variety of cannabis products used, the many types of endocannabinoids and their biological pathways and the variability of ADHD presentation in people. Teasing all these factors apart, she says, "is super complicated." In addition, cannabis researchers are hobbled by legal restrictions around marijuana.
Co-author Brooke Worster, MD , who specializes in pain management and palliative care, says she suspected the published evidence would be sparse. When that was indeed what they found, "I wasn't super surprised," she says. "Still, it is shocking how many holes there are. We have a lot of work ahead."
Drs. Ryan and Worster plan to publish results from a second survey of cannabis use in adults with ADHD.
