Cannabinoid Hyperemesis is a previously undiagnosed disorder which occurs in susceptible individuals and is characterised by ongoing cannabis abuse over many years, cyclical episodes of vomiting and compulsive bathing behaviour.The hyperemesis is delayed for several years prior to the onset of illness, and for several weeks or months with a return to regular cannabis use following a period of abstinence. Cessation of cannabis is curative.                                                                                                                                                                                                                                                

South Australia has had liberal laws[1] for many years regarding the possession of Cannabis plants in comparison to other parts of the world.  Many South Australians have two or three plants in their back gardens for their own domestic use[2].

 

Within our area of the Adelaide Hills it has only recently become apparent that much of what might have previously been described as psychogenic vomiting is a cannabis related illness.

 

This disorder is characterised by:

 

(1) A history of several years of cannabis abuse prior to the onset of  hyperemesis in susceptible individuals.

(2) The hyperemesis will follow a cyclical pattern every few weeks or months, often for many years, against a background of regular cannabis abuse.

(3) Cessation of cannabis leads to cessation of the hyperemesis in the presence of a negative urine drug screen for cannabinoids.

(4) A return to cannabis use will see a return of the hyperemesis many weeks or months later.

(5) The patient will compulsively bathe i.e. will take multiple hot showers or baths during the acute phase of the illness in an attempt to quell the hyperemesis.

 

The patho-physiology is as follows:

 

(a) Susceptible patients develop a hypersensitivity to cannabis following several years of exposure.

(b) Cannabis has a long half-life of weeks or months in the body. Regular use is accumulative and this gives rise to toxicity in the hypersensitive patient.

(c) It has been shown that cannabis delays gastric emptying[4] and in the toxic patient this may lead to gastric stasis and hence hyperemesis.

(d) The patient may compulsively bathe because of the presence of the cannabinoid receptors in the limbic system of the brain[3].  The toxicity may disrupt the thermoregulatory systems of the hypothalmus and this disruption might settle with hot bathing or showering.

 

Three cases of Cannabinoid Hyperemesis are presented here.[See Table 1].They compare very similarly with a case described by Dr.Gregory de Moore in 'Psychogenic vomiting complicated by marijuana abuse and spontaneous pneumomediastinum'[5].  In this article we have a man described as a psychogenic vomiter who has smoked marijuana as a teenager, developed a cyclical vomiting syndrome in his twenties and is noted to compulsively bathe.  A year following psychotherapy he is still smoking marijuana and still vomiting.

 

 [Insert Table 1. Here]

REFERENCES              

 

[1] South Australia:Controlled Substances Act 1984.

[2] South Australia: Controlled Substances Act- Expiation of Simple Cannabis Offences 1987.                                                                                 

[3] Her Ken Ham M. et al. "Cannabinoid receptor localization in the brain." Proc Nath.Acad..Sci.USA 1990;87: 1932-1936.                                                                                   

[4]McCallum R.W. et al. "delta-9-Tetra Hydro Cannabinoid delays the gastric emptying of solid food in humans-a double blind randomized study." Alimentary Pharmacology and Therapeutics 13 [1];77.80 1999 June.

[5]deMoore G.M. Baker J. Bui.T. "Psychogenic Vomiting complicated by Marijuana abuse and spontaneous pneumomediastinum."Australian and New Zealand Journal of Psychiatry 30[2]; 290-4 1996 April.