Researchers have found clear associations between marijuana use in young males and cyclic vomiting syndrome (CVS), where patients experience episodes of vomiting separated by symptom free intervals.

The study, published in the January issue of Neurogastroenterology and Motility, looked at 226 patients seen at the Mayo Clinic in Rochester, New York, USA, over a 13-year period.

These were broken into three groups. Eighty-two patients with CVS were randomly matched with 82 patients with Irritable Bowel Syndrome (IBS) based on age, gender and geographic referral region. Researchers also examined the records of 62 patients with functional vomiting (FV), recurrent vomiting that cannot be attributed to a specific physical or psychiatric cause.

"Our study showed that CVS and FV had very similar clinical features, apart from marijuana use" says Dr G Richard Locke III from the Division of Gastroenterology and Hepatology at the Clinic.

Key findings of the study included:

    Members of the CVS group were younger than members of the FV group (30 versus 36 years) and more likely to be male (53% versus 46%).
    No statistically significant association was detected between membership of the CVS and FV groups and marital status, education level, body mass index, employment status, alcohol use or smoking history.
    37% of the CVS group had used marijuana (81% male), together with 13% of the FV group (equally split between male and female) and 11% of the IBS group (73% male).
    Marijuana users were 2.9 times more likely to be in the CVS group than the FV group. When this was adjusted for age and gender, males using marijuana were 3.9 times more likely to be in the CVS group and women using marijuana were 1.2 times more likely.

The research team also looked at gastrointestinal symptoms and migraine as these have previously been associated with CVS. They found that

    The prevalence of gastrointestinal symptoms, including abdominal pain and nausea, was similar in CVS and FV patients, with the exception of retching, which was more common in patients with CVS (69% versus 31%).
    Patients in the CVS group were more likely to have headaches and migraines than patients in the FV group, but the difference was not statistically significant. Migraine headache and psychiatric disorders did not appear to commonly co-exist in CVS patients, unlike in the IBS group.
    The researchers also measured rapid gastric emptying, which is when undigested food enters the small bowel too quickly causing nausea, vomiting and other symptoms. This showed that there were much higher rates of fast gastric emptying in patients in the CVS and FV group (45% and 46% respectively), compared with the IBS group (8%). A novel finding was that the patterns of fast, normal and delayed gastric emptying were similar in the CVS and FV groups.

"Our study confirms that cyclic vomiting syndrome occurs most often in young males and is significantly associated with marijuana use, unlike functional vomiting" says Dr Locke. "The current treatment options for this condition remain challenging and are limited by the lack of randomised controlled trials. Further research is clearly needed."