Abstract
Distinguishing between cannabinoid hyperemesis syndrome and cyclic vomiting syndrome (CVS) in patients with cyclical vomiting and heavy cannabinoid use is a significant diagnostic challenge. A critical consideration is catamenial CVS, a subtype of CVS in which vomiting episodes are closely linked to the menstrual cycle. This pattern is frequently overlooked in cannabinoid users due to the overlapping symptomatology of both conditions. However, identifying a menstrual association with vomiting episodes is crucial for diagnosing catamenial CVS because hormonal contraceptive therapy is an effective treatment. We present 2 adolescent cases of cyclical vomiting with cannabis use, where further clinical investigation revealed the menstrual cycle as a key trigger for vomiting, ultimately leading to successful treatment with hormonal contraception despite continued cannabis use. Clinicians should always consider menstrual history in patients with cyclical vomiting to facilitate early and accurate diagnosis and timely treatment of catamenial CVS.