People who vape cannabis develop a debilitating vomiting disorder far sooner than those who smoke flower. That is the headline finding from a new study into chronic cannabis use disorder, which surveyed more than 1,000 sufferers. The research adds urgency to a condition that still catches many by surprise.

The study appeared in March 2026 in Cannabis and Cannabinoid Research. Researchers from the University of California, Irvine gathered self-reported data from 1,134 participants. Each person had either received a formal diagnosis or strongly suspected they had CHS. It ranks among the largest surveys of its kind to date.

What Is Chronic Cannabis Use Disorder?

Chronic cannabis use disorder can trigger a severe vomiting condition known as cannabinoid hyperemesis syndrome (CHS) in some long-term users. It produces cyclical episodes of intense nausea and vomiting, often paired with severe abdominal cramping. Episodes can be serious enough to land patients in hospital.

The condition moves through three recognised phases. The prodromal phase brings early morning nausea and stomach discomfort. Many people mistake these symptoms for an unrelated gut problem. Next comes the hyperemetic phase. Vomiting becomes severe and relentless, sometimes continuing for several days. Dangerous dehydration is a real risk if the episode goes untreated. The recovery phase begins once cannabis use stops, though symptoms often return when use resumes.

CHS places a growing strain on healthcare systems. In the United States, an estimated 2.75 million people are affected each year. Hospital emergency visits linked to the condition doubled between 2017 and 2021. In Ontario, Canada, emergency department visits for CHS rose 13-fold between 2014 and 2021 following cannabis legalisation.

Vaping Speeds Up the Path From Heavy Cannabis Use to CHS

The study’s standout finding concerns how cannabis reaches the body. Participants who exclusively vaped developed CHS symptoms notably sooner than those who exclusively smoked flower. Researchers confirmed this difference was statistically significant.

Vape cartridge users also reported using cannabis more often. Both factors, the pharmacological profile of vapourised THC and the ease of frequent dosing, appear to accelerate the path to illness.

Researchers offer several possible explanations. Vapourised cannabis typically carries higher THC concentrations. It also hits the bloodstream faster, producing sharper peaks than smoked flower. That rapid delivery may speed up dysregulation of cannabinoid receptor 1 (CB1), a mechanism researchers increasingly link to CHS. Additives, solvents, and terpenes in cartridge formulations could also contribute. The study authors note this remains speculative and needs further investigation.

How Chronic Cannabis Use Disorder Shapes the Risk Profile

The survey produced a consistent picture of who develops CHS. A striking 96.5% of respondents used cannabis at least once daily. Around 45% used it six or more times a day when symptoms first appeared.

Most participants had used cannabis for years before CHS emerged. Nearly two thirds (65.4%) reported more than three years of heavy cannabis use before symptoms began. Another 26.2% had been using for over a decade. Only 3.9% developed symptoms within six months of starting.

Delta-9-THC dominated the products participants used, with 59.5% identifying it as the main cannabinoid. Crucially, CHS symptoms appeared regardless of where people sourced their cannabis. Licensed dispensaries, the unlicensed market, home cultivation, and hemp retailers all produced the same outcome. That consistency makes a single shared contaminant an unlikely explanation.

Smoking flower remained the most common method overall, reported by 75.8% of participants. Vape cartridges followed at 51.2%, then dabbing concentrates at 16.9%, and edibles at 15.5%.

Women Experience Greater Symptom Burden

The research highlights clear differences between male and female experiences of CHS. Women reported more symptoms across both the prodromal and hyperemetic phases. They also experienced longer episodes. Men more commonly reported episodes that resolved within a single day. Women were significantly more likely to endure episodes lasting three days or more.

Over a third of female respondents (37.8%) said their symptoms worsened around menstruation. Researchers suggest hormonal factors may play a role. Sex-based differences in metabolism and body composition, particularly higher adiposity in women, could slow the clearance of cannabinoid metabolites and extend episode duration.

The Importance of Early Warning Signs

The prodromal phase offers the clearest opportunity for early intervention. Yet researchers describe it as historically overlooked. Only 3.8% of participants reported no prodromal symptoms at all.

For most people, early morning nausea arrived first. Some 63.1% reported prodromal symptoms clustered between 4am and noon. Other early signals included stomach pain (66.5%), appetite changes (51.7%), and anxiety (48.3%). Spotting this pattern earlier could give both patients and clinicians a vital window to act before full hyperemetic episodes take hold.

Lead author Dr Codi Peterson of the University of California, Irvine, stressed that better awareness of these use patterns and symptom profiles can support earlier recognition and more effective management in acute care settings.

A Growing Public Health Concern

Doctors first described CHS in medical literature in 2004. For years the condition remained poorly understood and routinely misdiagnosed. A dedicated International Classification of Diseases code for CHS only arrived in 2025. That change should improve how accurately the condition gets counted and tracked.

Cannabis use has expanded rapidly across many countries. High-potency vape products have spread alongside it. CHS emergency visits continue to climb. Recognising the signs of chronic cannabis use disorder has never been more important.

The study’s authors called for standardised clinical questionnaires covering cannabis use and CHS-specific symptoms. They also urged wider adoption of unified diagnostic criteria. Both steps would build a stronger evidence base and support better prevention and care.

Source: dbrecoveryresources