Regular cannabis use is linked to withdrawal, dependence, and a growing list of physical health risks, doctors say. (AP Photo/Andrew Selsky, file)
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In the United States, the trend of regular or daily cannabis use is on the rise. Between 1992 and 2022, the rate of daily or near-daily cannabis consumption per person increased fifteen times. Currently, 40% of those who used cannabis in the last month now use it daily or nearly every day.
Cannabis use has now surpassed alcohol use. In 2022, 17.7 million Americans reported using cannabis daily or almost daily, compared to 14.7 million who drank alcohol with the same frequency. This marks the first time cannabis has overtaken alcohol in this aspect.
The potency of cannabis has also seen a significant increase. In 1995, samples showed an average of less than 4% THC, but by 2022, this average had risen to about 16%. Meanwhile, CBD content has decreased, which is significant because CBD can mitigate some of THC’s psychoactive effects. Consequently, today’s cannabis is not only more potent but has also lost some of its natural balancing effect.
One of the health concerns associated with cannabis use is cannabis hyperemesis syndrome (CHS). This condition leads to repeated bouts of vomiting, often severe enough to warrant emergency room visits or even hospitalization. The CDC recorded nearly 200,000 ER visits for CHS from January 2023 to May 2026.
As an ER physician, I frequently encounter CHS cases. Patients typically arrive at the ER with severe vomiting and abdominal pain, often after using cannabis multiple times daily for years. When informed that cannabis is causing their symptoms, patients often react with shock and disbelief.
This is just one of the health risks linked to regular cannabis use. The following examines the physical effects of regular use, withdrawal symptoms, health risks, and the steps patients and healthcare providers should take with this information.
Effects of Regular Cannabis Use on the Body
Contrary to popular belief, cannabis can be addictive with regular use. PET imaging studies of frequent cannabis smokers revealed a 20% downregulation of cortical CB1 receptors, which THC binds to. This downregulation is linked to the duration of use.
This explains two common experiences among regular users: the development of tolerance and the gradual decline of anxiety relief that initially made cannabis attractive. The brain adjusts, requiring more of the drug to achieve the same effects.
Withdrawal symptoms often follow cessation among regular users. A meta-analysis in JAMA Network Open involving 23,518 participants found that 47% experienced withdrawal symptoms. These symptoms include irritability, anxiety, sleep disturbances, vivid dreams, appetite loss, restlessness, and low mood, often clustering in the first week after stopping use.
A systematic review found that 22% of cannabis users meet the criteria for cannabis use disorder, indicating a dependence on the drug. This risk increases to 33% among young people who use weekly or daily.
People often cite sleep as a reason for nightly use, and it’s also the reason many fail to quit. THC reduces the time to fall asleep but suppresses REM sleep. When use stops, REM sleep returns intensely, often causing vivid, unpleasant dreams and insomnia. This withdrawal symptom typically resolves within one to two weeks, but it can drive people back to daily use even if they want to quit.
Physical Effects of Cannabis: Psychosis, Heart Disease, Cognition, and Lung Cancer
A study in The Lancet Psychiatry compared 901 first-episode psychosis patients to 1,237 controls. It found that daily cannabis use increased the likelihood of a psychotic disorder by 3.2 times compared to non-users, rising to 4.8 times with high-potency products (10% THC or higher).
Another study in JAMA Network Open involving over 13 million Ontario residents indicated that cannabis use disorder contributed to new schizophrenia diagnoses, increasing from 3.7% to 10.3% after legalization. This was most pronounced in men aged 19 to 24.
Regarding cardiovascular health, a study of 434,104 individuals linked daily cannabis use to a 25% increase in myocardial infarction odds and a 42% increase in cerebrovascular event odds, with stronger associations among non-tobacco smokers: 49% for heart attacks and 116% for strokes.
In terms of cognition, a large brain imaging study involving over 1,000 young adults examined various cognitive tasks. Heavy cannabis use (over 1,000 exposures) was associated with lower brain activation during memory tasks, impacting verbal memory and intelligence.
Older studies suggesting no link between cannabis use and lung cancer are now being questioned. A recent study tracking around 150,000 participants found a 3.9 relative risk of lung cancer among those with cannabis use disorder.
Implications of New Data for Regular Cannabis Users
The frequency and potency of cannabis use significantly influence risk. Monthly low-dose edibles differ greatly from daily concentrate use.
To assess dependence, users can stop for two weeks. If irritability, insomnia, and appetite loss occur, dependence may be present.
Cyclic vomiting in daily users is often related to cannabis, and cessation is the only effective treatment. Traditional anti-nausea medications are ineffective, though topical capsaicin and hot showers may provide temporary relief. Repeat ER visits are common, where intravenous haldol is often used to manage symptoms.
The risk-benefit balance is most unfavorable for those under 25, as the brain is still developing and the risk of psychosis is higher.
The U.S. has commercialized cannabis quickly, and the understanding of its risks is catching up. This does not suggest a return to criminalization but emphasizes the need for awareness of the effects of daily high-potency THC use. Clear communication similar to that used for alcohol and tobacco is essential, and most patients are open to hearing it, having never been informed before.
