Despite the justified concern about rising opiate use in the United States, cannabis remains the most commonly used substance in the 12- to 17-year-old population.1 Cannabis use is widespread, particularly in states in which it has been decriminalized or legalized. While use of alcohol and nicotine has fallen among high school students from the years 2010 to 2015, marijuana use has remained relatively constant.2 In addition, the potency of cannabis with regard to tetrahydrocannabinol (THC) content has increased over the years. Despite the common belief among the public that cannabis use is benign, accumulating research is revealing a number of concerning consequences, especially in vulnerable populations and those who use cannabis regularly.

Case summary

Adam is a 17-year-old boy with a past history of social anxiety treated with psychotherapy at age 14. He presents to the emergency department with nausea, vomiting, and abdominal pain. He had presented to the ED six times in the past 2 months with a similar presentation. On previous occasions, he had received multiple abdominal ultrasounds, two abdominal CTs, an upper endoscopy, and had been treated with a proton pump inhibitor for presumed gastroesophageal reflux. None of the investigations had been revealing and the empirical treatment for reflux was not effective. On presentation to the ED this time, his temperature was 36.7° C, pulse 72 beats per minute, respirations 12 breaths per minute, and blood pressure 112/66 mm Hg. Physical exam was normal. Laboratory examination showed a normal metabolic panel and complete blood count. Serum transaminases were normal as was lipase and amylase. Urinalysis was normal, but urine toxicology screen was positive for THC. This prompted further history taking with the patient and family. The patient stated that he smokes one to three bowls daily. Nausea typically has its onset a few hours after the inhalation. His mother reported that the only thing that she had noticed that was different was that the patient was now taking very long, hot showers. The patient stated that a hot shower relieved the symptoms.

Case discussion

Adam may be suffering from cannabinoid hyperemesis syndrome. While cannabis has been used for nausea and hyperemesis associated with chemotherapy, it also can be a cause of hyperemesis. It should be considered in any individual who has cyclical vomiting of unexplained etiology, especially when the telltale sign of associated hot baths/showers for relief is present, as it is in approximately 60% of cases.3 This is one of the “paradoxical” actions of cannabis wherein some individuals experience reduction in nausea while others experience more nausea. Similarly, some individuals experience dysphoria, rather than euphoria, and some experience increases in anxiety, rather than relief of anxiety. With regard to psychosis, studies suggest that regular cannabis use is associated with a doubling of the risk of a psychotic illness and may be particularly harmful for those who are vulnerable because of a personal or family history of psychosis or bipolar disorder.4 Clearly, for certain individuals, cannabis use is hardly benign and can cause medical problems over and above the psychosocial problems that it can induce. Cannabis also is associated with an increased risk of motor vehicle crashes.

Treatment for these adverse effects of cannabis is cessation of the drug. This can be accomplished through hard work with a counselor, who may recommend any of a number of treatments, including contingency management, cognitive behavioral therapy, systematic multidimensional family therapy, and motivational enhancement therapy, among others.5 While common lore is that it is impossible to stop cannabis use, the effect sizes of these treatments is in the moderate to large range. There are viable options to stop cannabis use, especially when it becomes problematic.

Dr. Althoff is associate professor of psychiatry, psychology, and pediatrics at the University of Vermont, Burlington. He is director of the division of behavioral genetics and conducts research on the development of self-regulation in children. Email him at .


1. “Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings,” Substance Abuse and Mental Health Services Administration Center for Behavioral Health Statistics and Quality, 2013.

2. “Monitoring the Future Survey, 2015,” National Institute on Drug Abuse.

3. Pharmaceuticals (Basel). 2012 Jul;5(7):719-26.

4. Nat Rev Neurosci. 2007 Nov;8(11):885-95.

5. Dtsch Arztebl Int. 2016 Sep;113(39): 653-9.