Sleep and psychoactive substances do not mix well. From cannabis to OTC sleep aids and opioids, common substances can have a profound impact on sleep, seldom for the better.
Marijuana and its constituent cannabinoids are often touted as the latest wonder drug in sleep medicine. But data are scarce and largely self-reported.
THC (tetrahydrocannabinol) is the primary psychoactive component in cannabis. CBD (cannabidiol) is more often associated with medicinal properties such as analgesia, neuroprotective, anti-inflammatory, antidepressant, and anxiolytic effects, noted Ashima Sahin, MD, FCCP, assistant professor of clinical medicine at the University of Illinois at Chicago. Dr. Sahin opened a prerecorded symposium on Sleep Disorders – Sleep and Substances: From Caffeine to Marijuana. The session is available for viewing on the virtual CHEST 2020 meeting platform through January 18, 2021, for registered attendees.
THC and CBD bind to receptors in the endocannabinoid system, which has physiologic functions in the central and peripheral nervous systems on memory, appetite, stress response, and reward/reinforcement pathways. Proponents suggest benefits for insomnia, PTSD-related nightmares, REM sleep behavior disorder, restless leg syndrome, and obstructive sleep apnea, among other conditions.
Cannabinoids have therapeutic promise, Dr. Sahin said, but there is little to no randomized controlled trial data in sleep disorders.
“Cannabinoids have differentiated impacts on sleep depending on dose, ratio of THC to CBD, timing and route of administration,” she said. “There is also a worrisome potential for dependence and tolerance as well as potential drug interactions.”
The evidence is clearer when it comes to over-the-counter sleep aids. Clinical guidelines from American Academy of Sleep Medicine recommend against the use of OTC sleep products containing diphenhydramine, melatonin, or valerian.
OTC products are less well-regulated than prescription products and can be far more dangerous than patients realize, noted Sunita Kumar, MD, FCCP, professor of pulmonary, critical care, and sleep medicine at Loyola University Medical Center and Vice-Chair of the CHEST Sleep NetWork.
Fifty milligrams of diphenhydramine have the same effect on driving as a blood alcohol level of 0.1%. Common side effects include blurred vision, constipation, urinary retention, increased intraocular pressure in glaucoma, plus psychomotor and cognitive impairment.
Herbal products such as valerian (Valeriana officianlinis) contain unpredictable amounts of active ingredient and may be contaminated with heavy metals.
OTC melatonin is similarly unpredictable. Commercial samples in a Canadian test showed more than 400% variation in active ingredient.
“It is important that we educate our patients that OTC products may not be safe and are not well-regulated,” Dr. Kumar said.
Caffeine and alcohol are the first and second most-used psychoactive substances in the US and both have adverse effects on sleep. Caffeine taken as long as 6 hours before bedtime reduces the quality and duration of sleep, said Andreea Anton, MD, FCCP, associate professor of medicine at the Medical College of Wisconsin and chief of medicine at Zablocki Veterans Affairs Medical Center in Milwaukee.
Alcohol is the most-used sleep aid in the US, she continued. Even low doses of alcohol can negatively impact sleep architecture.
Opioids, both prescription and illicit, are a major factor in sleep-disordered breathing. Opioids reduce sleep efficiency, reduce slow wave and REM sleep, and reduce arousal thresholds.
“We should have a very low threshold to order sleep testing in patients taking opioids who complain of sleep disruption or daytime sleepiness,” said Lauren Tobias, MD, assistant professor of medicine at Yale School of Medicine and director of the Sleep Program at the VA Connecticut Health System. “There is no clear threshold of opioid dosing in sleep disturbance, but anyone taking more than 200 morphine milligram equivalents of any opioid daily is all but guaranteed to have sleep-disordered breathing.”