Links between Cannabinoid Hyperemesis Syndrome symptoms and drug use, mental health problems, antisocial behavior, and personality in a national survey of adults in the United States

A 2025 national survey of US adults reveals that individuals experiencing Cannabinoid Hyperemesis Syndrome (CHS) symptoms exhibit significantly higher rates of polysubstance use, psychiatric disorders, antisocial behavior, and dysfunctional personality traits compared to other cannabis users and non-users.

The Gist

Imagine your body is a high-performance car. For most people, putting a little bit of fuel (cannabis) in the tank is fine, or maybe even helpful for a short ride. But for a specific group of drivers who have been running that engine at maximum speed, day in and day out, for years, the car starts to sputter, overheat, and eventually, the engine starts throwing a massive tantrum.

This "engine tantrum" is what doctors call Cannabinoid Hyperemesis Syndrome (CHS). It's a condition where heavy, long-term cannabis users start suffering from uncontrollable nausea, vomiting, and stomach pain.

This new study is like a massive "driver's report card" for the United States. The researchers didn't just look at the car's engine (the vomiting); they looked at the driver's entire life to see what else was going on under the hood. They compared three groups of people:

1. The "CHS Drivers": Heavy users who are currently vomiting and in pain.
2. The "Heavy Drivers": People who use cannabis daily but aren't vomiting.
3. The "Casual Drivers": People who use it occasionally or not at all.

Here is what the report card revealed, translated into everyday language:

1. The "All-You-Can-Eat" Drug Buffet

If you think the CHS group only uses cannabis, think again. They are the ones with the most chaotic pantry.

• The Analogy: Imagine a buffet. The casual drivers might grab a salad and a soda. The heavy drivers might grab a burger and fries. But the CHS group? They are grabbing the burger, the fries, the soda, the dessert, the spicy wings, and the extra hot sauce all at once.
• The Finding: People with CHS symptoms were much more likely to use other drugs alongside cannabis, including opioids (painkillers), sedatives (sleeping pills), and hallucinogens. They also had a much higher rate of drug overdoses. It's as if their bodies are trying to "fix" the nausea by piling on more substances, which only makes the problem worse.

2. The Emotional Storm Cloud

The study looked at the drivers' mental weather.

• The Analogy: While the casual drivers might have a few scattered clouds, and the heavy drivers might have a rainy day, the CHS group is living in a permanent hurricane.
• The Finding: This group reported significantly higher levels of depression, anxiety, and sleeplessness. They also felt a lot more physical pain and rated their overall health as "poor." They felt like they were drowning in a storm that the other groups barely noticed.

3. The "Wild West" Behavior

The researchers also checked the drivers' behavior on the road.

• The Analogy: If the casual drivers follow the speed limit and the heavy drivers might occasionally run a red light, the CHS group is driving with their hands off the wheel, swerving, and getting into fender benders.
• The Finding: This group had higher rates of "antisocial behavior" (like theft or aggression) and was much more likely to be involved in fights or violence with their romantic partners (both as the person starting the fight and the person getting hurt). They also felt a deep sense of powerlessness, like they were passengers in their own lives rather than the drivers.

4. The Personality "Leak"

Finally, they looked at the drivers' personality "tires."

• The Analogy: Imagine personality traits as tires. Most people have tires that hold air well (conscientiousness, feeling good about life). The CHS group's tires seem to be leaking air. They showed "disinhibited" traits—meaning they struggle to control their impulses, are more aggressive, and feel less responsible for their actions.
• The Finding: They scored lowest on "conscientiousness" (being organized and responsible) and highest on "negative urgency" (doing reckless things when stressed).

The Big Picture: Why This Matters

Think of CHS not just as a stomach bug, but as a canary in a coal mine.

When a person shows up with CHS symptoms, it's not just their stomach that is screaming for help. It's a signal that their entire life system is under immense stress. They are likely juggling multiple addictions, battling severe depression, and struggling with relationships and impulse control.

The Takeaway:
If a doctor only treats the vomiting (the engine noise) but ignores the chaotic driving, the stormy weather, and the other drugs in the car, the patient will likely keep crashing. This study suggests that to help these people, we need a full-service repair shop. We need to treat the nausea, yes, but we also need to help them with their mental health, their other drug use, and their life struggles all at the same time.

The CHS group isn't just "sick"; they are the most vulnerable group in the cannabis-using population, carrying the heaviest load of psychological and behavioral challenges.

Technical Summary

1. Problem Statement

Cannabis use patterns in the United States have shifted toward higher potency and increased frequency of heavy use over the last two decades. Cannabinoid Hyperemesis Syndrome (CHS) is a condition characterized by recurrent episodes of severe nausea, vomiting, and abdominal pain in chronic heavy cannabis users. While previously identified primarily in acute care settings, recent estimates suggest the prevalence is significantly higher in the general population (approx. 18% of daily users, or ~7 million US adults).

Despite the growing prevalence, there is a lack of comprehensive data characterizing the psychosocial, behavioral, and psychiatric profile of individuals with CHS symptoms compared to other cannabis users. It remains unclear whether CHS represents a distinct high-risk subgroup with unique comorbidities (e.g., polysubstance use, severe mental illness, antisocial behavior) or if these issues are simply correlated with heavy cannabis use in general. This study aims to fill that gap by comparing CHS symptomatology against daily cannabis users without CHS, less frequent users, and non-users.

2. Methodology

Study Design and Sample:

• Data Source: The National Firearms, Alcohol, Cannabis, and Suicide (NFACS) survey, a nationally representative cross-sectional survey of U.S. adults conducted in 2025 ($N = 7,034$).
• Recruitment: Random address-based sampling (ABS) and mobile messaging (MMS/SMS) via Verasight.
• Weighting: Data were weighted to match July 2025 Current Population Survey benchmarks for demographics (age, sex, race, income, education, region, etc.).
• Ethics: Exempt determination by the University of Michigan IRB; active consent obtained.

Group Classification:
Participants were stratified into four distinct groups based on cannabis use history and symptom endorsement:

1. CHS Symptom Group ($n=191$): Endorsed daily/near-daily cannabis use in the past 5 years AND periods of severe nausea, vomiting, or abdominal pain.
2. Daily Cannabis Use Group ($n=882$): Endorsed daily/near-daily use in the past 5 years BUT no CHS symptoms.
3. Less-Than-Daily Cannabis Use Group ($n=1,288$): Cannabis use in the past 12 months, but not daily/near-daily.
4. No Cannabis Use Group ($n=4,673$): No cannabis use in the past 12 months.

Measures:

• Substance Use: Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST); AUDIT items; lifetime and past-12-month overdose/poisoning history.
• Mental Health: PHQ-2 (depression), GAD-2 (anxiety), NIH Toolbox Social Support scales.
• Physical Health: Sleep problems (Jenkins scale), Pain (PEG scale), self-rated overall health.
• Behavioral/Social: Antisocial behavior scale (theft, aggression, arrests), Intimate Partner Violence (perpetrator and victim scales).
• Personality: Scales for antagonism, conscientiousness, negative urgency, persecutory ideas, desire for power/powerlessness, and subjective well-being.

Statistical Analysis:

• Logistic and linear regression models were used to compare groups.
• Analyses utilized Stata 19 with survey weights to adjust for design effects.
• Effect sizes were reported as Cohen's $d$.
• Bonferroni corrections were applied for post-hoc pairwise comparisons.

3. Key Contributions

• First National Profile: Provides the first large-scale, nationally representative characterization of the CHS population in the general U.S. adult community, moving beyond clinical samples.
• Differentiation from Heavy Use: Crucially, the study isolates CHS symptoms from general "daily cannabis use," demonstrating that CHS represents a distinct, higher-risk subgroup even among daily users.
• Multidimensional Risk Profile: Establishes a comprehensive "high-risk profile" linking CHS not just to gastrointestinal issues, but to a constellation of polysubstance use, severe psychopathology, and antisocial behavior.

4. Key Results

Substance Use and Overdose:

• Polysubstance Use: The CHS group reported the highest lifetime rates and greatest variety of drug use across all classes (opioids, hallucinogens, sedatives, stimulants).
• Overdose Risk: The CHS group had significantly higher lifetime rates of drug overdose (21.0%) compared to daily users without CHS (7.4%) and non-users (1.9%).
• Specific Correlates: CHS was strongly associated with "downer" drugs (opioids, sedatives, heroin/fentanyl) and alcohol poisoning. While daily users also had higher rates than non-users, the CHS group consistently showed the highest prevalence.

Mental Health and Physical Well-being:

• Psychopathology: The CHS group exhibited significantly higher levels of depression (mean $d = 0.84$) and generalized anxiety (mean $d = 0.90$) compared to all other groups.
• Physical Health: They reported the most severe sleep problems, highest pain ratings, and lowest self-rated overall health.
• Social Support: The CHS group reported the lowest levels of perceived social support.

Antisocial Behavior and Violence:

• Antisocial Behavior: The CHS group showed the highest rates of antisocial behavior (theft, destruction of property, aggression), with a large effect size compared to non-users ($d = 1.32$).
• Intimate Partner Violence (IPV): The CHS group was significantly more likely to be both perpetrators ($d = 0.71$) and victims ($d = 0.73$) of IPV compared to daily users and non-users.

Personality Traits:

• The CHS group displayed a dysfunctional personality profile characterized by:
  • High Negative Urgency (impulsivity under distress; $d = 0.72$).
  • High Antagonism and Persecutory Ideas.
  • Low Conscientiousness ($d = -0.59$).
  • Low Subjective Well-being and high feelings of powerlessness.

Comparative Findings:

• While daily cannabis users (without CHS) generally fared worse than non-users, the CHS group was statistically distinct and significantly worse than the daily user group across almost all metrics (substance variety, mental health, violence, personality).
• The effect sizes for differences between CHS and non-users were consistently large (often $d > 0.9$), indicating a profound psychosocial deficit associated with CHS symptoms.

5. Significance and Implications

Clinical Implications:

• Beyond Acute Care: The findings suggest that treating CHS requires more than just managing acute nausea/vomiting (e.g., antiemetics, hot showers). Clinicians must screen for and address severe comorbidities, including polysubstance use disorders, depression, anxiety, and interpersonal violence.
• Treatment Engagement: The high levels of antisocial behavior, low conscientiousness, and poor subjective well-being suggest that individuals with CHS may face significant barriers to treatment engagement. Integrated care models addressing both substance use and mental health are likely necessary for successful outcomes.

Public Health and Policy:

• Risk Stratification: The study identifies a specific "high-risk" phenotype within the cannabis-using population. Public health interventions should target this subgroup for overdose prevention and mental health support.
• Diagnostic Criteria: The results support the validity of CHS as a distinct clinical entity with a unique psychosocial profile, rather than merely a symptom of general heavy cannabis use.

Limitations:

• Causality: As a cross-sectional survey, causality cannot be established (e.g., whether drug use causes CHS or CHS drives drug use).
• Self-Report: Data relies on self-reported symptoms and behaviors, which may be subject to recall bias.
• Diagnostic Specificity: The CHS criteria used were sensitive but not specific; some participants may have gastrointestinal issues unrelated to cannabis, though the authors note that the "over-inclusive" nature likely biases results toward the null, making the detected differences even more robust.

In conclusion, this study establishes that adults with CHS symptoms represent a highly vulnerable population characterized by a convergence of severe substance use disorders, psychiatric morbidity, and antisocial behaviors, necessitating a holistic, multidisciplinary approach to care.