Elevated suicidal thoughts and behaviors among adults reporting symptoms of Cannabinoid Hyperemesis Syndrome: Results from a national survey of US adults

A national survey of US adults reveals that individuals experiencing symptoms of Cannabinoid Hyperemesis Syndrome report significantly higher rates of suicidal thoughts, behaviors, and associated psychological distress compared to daily cannabis users without the syndrome.

The Gist

Imagine your body is a car, and cannabis is the fuel. For most people, this fuel runs the engine smoothly. But for a small, specific group of heavy users, something goes wrong with the engine's cooling system. This condition is called Cannabinoid Hyperemesis Syndrome (CHS). Instead of running smoothly, the car starts overheating, shaking violently, and spewing smoke (severe nausea, vomiting, and stomach pain) in unpredictable, recurring bursts.

This new study is like a mechanic's report card. It asks a big, scary question: When your car is breaking down this badly, how does it affect the driver's mind?

Here is the breakdown of the findings using simple analogies:

1. The "Broken Engine" Group vs. The "Heavy Drivers"

The researchers looked at four groups of people:

• Group A (The CHS Group): Heavy users whose "engines" are broken (severe nausea/vomiting).
• Group B (The Heavy Drivers): People who use cannabis every day, but their "engines" are fine (no vomiting).
• Group C (The Occasional Drivers): People who use cannabis sometimes but not daily.
• Group D (The Non-Drivers): People who don't use cannabis at all.

The Finding:
The study found that Group A (The Broken Engine) was in the most trouble. While Group B (Heavy Drivers) had more problems than Group D (Non-Drivers), Group A was in a league of their own. They were significantly more likely to feel hopeless, think about suicide, or even try to end their lives compared to everyone else, including the other heavy users.

2. The "Perfect Storm" Analogy

Why is the CHS group so much worse off? Think of it like a perfect storm.

Usually, heavy cannabis use is like driving in the rain (risky, but manageable). But for the CHS group, it's like driving in a hurricane while your brakes are cut, your windshield is shattered, and you are being hit by lightning.

• The Physical Pain: The vomiting and pain are relentless and unpredictable. It's like being trapped in a room where the floor keeps dropping out from under you.
• The Mental Toll: Because the pain is so bad and won't go away, people start feeling trapped (like a mouse in a maze with no exit) and defeated (like a boxer who has been knocked down one too many times).
• The Burden: They feel like a burden to their families because they can't work or function.

The study found that these feelings of being "trapped" and "a burden" were much stronger in the CHS group than in any other group.

3. The "Warning Lights"

The researchers looked at "warning lights" on the dashboard of the human mind. They found that the CHS group had almost every warning light flashing red:

• Thoughts of suicide: They thought about it more often.
• Planning: They thought more about how to do it.
• Attempts: They actually tried to hurt themselves more often.
• Self-harm: They were more likely to cut or burn themselves without wanting to die, just to feel something other than the stomach pain.

Even when compared to other daily cannabis users (who are already at higher risk than non-users), the CHS group was twice as likely to have these severe thoughts and behaviors.

4. The "Snowball Effect"

Imagine a snowball rolling down a hill.

• Base layer: Heavy cannabis use.
• Middle layer: Other drug use, anxiety, depression, and personality traits that make life harder.
• Top layer: The CHS symptoms (the vomiting and pain).

For the CHS group, the snowball has become a massive, unstoppable boulder. The physical sickness makes the mental health worse, and the mental health makes it harder to deal with the sickness. It creates a cycle where the person feels like there is no way out, leading to a much higher risk of suicide.

The Bottom Line

This study is a wake-up call for doctors and families. If you see someone who uses cannabis heavily and is suffering from constant, severe vomiting and stomach pain, do not just treat the stomach.

Think of them as a person whose car is on fire. You can't just put out the fire; you have to check the driver for injuries, too. The study suggests that these individuals are in a unique, high-risk category. They need help with their physical pain, their mental health, and their substance use all at the same time, or the "fire" might consume them completely.

In short: The physical pain of CHS isn't just a stomach ache; it's a heavy weight that pushes some people to the very edge of their mental limits, making them much more likely to think about or attempt suicide than even other heavy cannabis users.

Technical Summary

1. Problem Statement

Cannabinoid Hyperemesis Syndrome (CHS) is an emerging disorder affecting heavy, chronic cannabis users, characterized by recurrent episodes of severe nausea, vomiting, and abdominal pain. While previous research has established that CHS is associated with high rates of comorbid psychiatric disorders, substance use problems, and poor physical health, the specific link between CHS symptoms and suicidal thoughts and behaviors (STB) had not been thoroughly quantified.

Given that heavy cannabis use is already linked to increased suicide risk, and CHS represents a severe subset of heavy users with significant physical and psychological distress, the authors hypothesized that individuals with CHS symptoms constitute a distinct, high-risk psychiatric subgroup with elevated rates of suicidality compared to other heavy cannabis users.

2. Methodology

Study Design and Data Source

• Survey: The study utilized data from the National Firearms, Alcohol, Cannabis, and Suicide survey, a nationally representative cross-sectional survey of US adults ($N = 7,034$).
• Data Collection: Conducted between May 27 and September 2, 2025, by Verasight using random address-based sampling (ABS) and mobile/text message recruitment.
• Weighting: Data were weighted to match July 2025 Current Population Survey benchmarks for demographics (age, sex, race, income, education, region, etc.).
• Ethics: The protocol was exempted by the University of Michigan IRB; all participants provided active consent.

Participant Grouping
The authors stratified the sample into four distinct groups based on cannabis use history and CHS symptom endorsement:

1. CHS Symptom Group ($n=191$): Reported daily/near-daily cannabis use in the past 5 years and episodes of severe nausea, vomiting, or abdominal pain.
2. Daily Cannabis Use Group ($n=882$): Reported daily/near-daily use in the past 5 years without CHS symptoms.
3. Past-Year Cannabis Use Group ($n=1,288$): Reported cannabis use in the past 12 months but not daily use.
4. No Cannabis Use Group ($n=4,673$): No cannabis use in the past 12 months (serving as a control).

Measures

• Suicidal Thoughts and Behaviors (STB): Assessed via 9 items covering lifetime and past 12-month experiences, including wishing to be dead, thoughts of killing oneself, planning, preparation, interrupted attempts, suicide attempts, and non-suicidal self-injury (NSSI). A latent trait score ($\theta$) was calculated using a two-parameter logistic response model.
• Suicide Risk Characteristics: Assessed using constructs from the Interpersonal Theory of Suicide (perceived burdensomeness, thwarted belongingness) and the Integrated Motivational-Volitional Model (defeat, entrapment). A latent trait score was calculated for these 11 items.

Statistical Analysis

• Logistic and linear regression models were used to compare groups.
• Analyses utilized Stata 19 with survey data modules to account for poststratification weights.
• Bonferroni adjustments were applied to control for Type I error in multiple pairwise comparisons.
• Effect sizes were reported as Odds Ratios (OR) for categorical outcomes and Cohen's $d$ for continuous outcomes.

3. Key Results

Lifetime Suicidal Thoughts and Behaviors

• The CHS group exhibited the highest prevalence of all nine STB indicators compared to all other groups.
• Comparison with Daily Users: Even when compared to daily cannabis users without CHS symptoms, the CHS group showed significantly higher rates. The mean Odds Ratio (OR) was 2.43 (indicating a 143% increase in odds). Seven of nine pairwise comparisons remained significant after Bonferroni correction.
• Comparison with Non-Users: The CHS group had a mean OR of 5.26 (over 400% increase) compared to those with no cannabis use in the past year.
• Effect Sizes: The CHS group showed medium-to-large effect size differences in continuous STB scores compared to daily users ($d = 0.57$) and non-users ($d = 1.12$).

Past 12-Month STB

• The CHS group had significantly higher rates of recent suicidal ideation and behaviors than all other groups (Mean OR = 4.28 vs. daily users).
• While fewer pairwise comparisons reached statistical significance after Bonferroni adjustment (likely due to lower base rates of recent events), the effect sizes were generally larger than those for lifetime prevalence, suggesting a strong association that may be underpowered for significance testing in this timeframe.

Suicide Risk Traits

• The CHS group reported significantly higher mean levels of defeat, entrapment, perceived burdensomeness, and thwarted belongingness compared to all other groups.
• Effect sizes for these risk traits were large when comparing CHS to non-users ($d \approx 0.86–0.96$) and medium-to-large when comparing CHS to daily users ($d \approx 0.55–0.67$).
• The CHS group also reported a higher mean number of past suicide attempts ($M=1.19$) compared to daily users ($M=0.43$) and non-users ($M=0.15$).

4. Key Contributions

1. Identification of a High-Risk Subgroup: The study provides the first national-level evidence that CHS symptoms identify a specific subgroup of cannabis users at exceptionally high risk for suicidality, distinct from and more severe than daily users who do not experience CHS.
2. Quantification of Risk: It quantifies the magnitude of this risk, showing that CHS symptoms add a significant layer of risk beyond heavy cannabis use alone (e.g., a ~150% increase in odds of lifetime STB compared to daily users without CHS).
3. Mechanistic Insights: By measuring specific psychological constructs (defeat, entrapment, burdensomeness), the study suggests that the chronic, cyclical, and debilitating nature of CHS symptoms (nausea/vomiting) likely exacerbates feelings of hopelessness and entrapment, driving suicide risk.
4. Clinical Implications: The findings argue that CHS is not merely a gastrointestinal issue but a complex medical-psychiatric condition requiring integrated care.

5. Significance and Limitations

Significance

• Clinical Practice: Healthcare providers treating CHS should screen for suicidal ideation and suicide attempts, as these patients represent a "perfect storm" of medical distress, substance use disorder, and psychiatric comorbidity.
• Public Health: As cannabis legalization increases access and potency, the prevalence of CHS is rising. This study highlights an urgent need for targeted suicide prevention strategies for this specific demographic.
• Research Direction: The study calls for longitudinal research to determine if CHS symptoms predict suicide mortality, noting that this group also has high rates of firearm ideation and overdose risk.

Limitations

• Cross-Sectional Design: Causality cannot be established; it is unclear if CHS causes suicidality or if underlying psychiatric factors predispose individuals to both.
• Self-Report Bias: CHS diagnosis was based on self-reported symptoms rather than clinical interview, potentially leading to misclassification.
• Statistical Power: The low prevalence of recent (past 12-month) suicidal behaviors in the general population limited the ability to detect significant differences after multiple comparison corrections, despite large effect sizes.
• Exclusion of Medical Differentials: The survey did not rule out other medical causes for nausea/vomiting (e.g., gastroparesis, bowel obstruction).

Conclusion
The paper concludes that adults reporting CHS symptoms are a unique, high-morbidity group warranting immediate clinical attention. Their risk profile suggests that treating the physical symptoms of CHS without addressing the accompanying psychiatric distress and suicide risk is insufficient. Comprehensive treatment models must address the interplay of medical, substance use, and mental health needs in this population.