Confirming the Diagnosis of Cannabinoid Hyperemesis

To the Editor: I was delighted to read the interesting case report by Chang and Windish¹ of 2 patients with cannabinoid hyperemesis and compulsive bathing. However, I was surprised by the authors' claim that these cases were the first reported in the United States. I found 3 other case reports that had already been published in the United States by simply searching PubMed and Google.^2-4 Although still rarely reported, cannabinoid hyperemesis may be much more common than currently recognized. Because this syndrome has been recognized only recently and its validity has been questioned,⁵ it is of paramount importance to clearly define and fully report all new cases.

The diagnosis is suggested by the characteristic triad of habitual cannabis use, cyclic vomiting, and compulsive bathing, but confirmation relies heavily on patient follow-up. Previous case reports and case series have shown that, almost universally, patients improve in the months after marijuana cessation, thus confirming the diagnosis. Unfortunately, adequate patient follow-up was lacking for the 2 cases by Chang and Windish, and the diagnosis remains uncertain. I hope that the authors can convey their patients' outcome and that a future issue of Mayo Clinic Proceedings might provide the necessary follow-up to confirm the suspected diagnosis.