For years, the Alcohol vs. Cannabis debate seemed settled for many people. Alcohol was viewed as the obvious villain, linked to violence, addiction, liver disease, and fatal crashes. Cannabis, by contrast, gained a reputation as the safer option, especially as legalization spread and medical use expanded. Yet psychiatrist Dr Daniel Amen says that assumption deserves serious reconsideration. His brain imaging research suggests that cannabis may cause more serious long-term damage than many people expect, even when compared with alcohol.
Dr Amen, founder of Amen Clinics and a leading voice in brain health research, recently revisited this comparison in a public discussion. “Now those of you who follow me know neither one are good for you,” he said. “And quite frankly, there are more deaths every year from alcohol than there are marijuana.” He acknowledged alcohol’s devastating toll, adding, “There’s more domestic violence, there’s more drunk driving accidents, there’s more bad decisions, people ending up in jail.” However, his own data complicates the idea that cannabis is the safer choice.
Dr Daniel Amen’s brain scan findings
Dr Daniel Amen’s work relies on single-photon emission computed tomography, or SPECT imaging, which measures blood flow and activity patterns in the brain. Using tens of thousands of scans, his team examined how different substances affect aging in key brain regions. “We did a study where we evaluated 62,454 spec scans, and then we looked at how the brain ages,” he said. The results showed accelerated brain aging in people who regularly used alcohol or cannabis. Surprisingly, cannabis produced the strongest association. Dr Amen has emphasized that accelerated brain aging is not a cosmetic issue.
Reduced blood flow and activity in certain brain areas are linked to poorer memory, impaired judgment, emotional instability, and a higher risk of neurodegenerative disease. In the study, cannabis users showed widespread reductions in blood flow across multiple regions, including areas tied to motivation and impulse control. Amen has repeatedly warned that damage in these areas can quietly undermine mental health, even in people who appear functional. While alcohol remains responsible for more deaths each year, Dr Amen argues that cannabis carries a different kind of risk. Alcohol often produces visible crises, such as accidents or arrests. Cannabis, in contrast, may slowly erode brain health over time. That distinction matters for psychiatrists, especially as high-potency products become more common and daily use increases among younger adults who assume long-term harm is unlikely.
A frightening new side effect puts cannabis in the spotlight
At the same time, emergency departments across several countries report more patients arriving with a cannabis-related condition that causes violent vomiting, nicknamed “scromiting.” Doctors first described cannabinoid hyperemesis syndrome more than a decade ago, but many clinicians still missed it. Cleveland Clinic explains that CHS happens when people experience cycles of nausea, vomiting, and abdominal pain after using cannabis for a long time. Patients often arrive in severe distress, unable to stop vomiting and sometimes screaming from pain, which inspired the slang term “scromiting.” Cedars-Sinai notes that CHS is a condition that leads to repeated and severe bouts of nausea, vomiting, and abdominal pain in daily, long-term users. In October 2025, the World Health Organization assigned CHS its own diagnostic code, and the United States health system adopted the same entry. This step means hospitals can finally track CHS systematically and separate it from other vomiting illnesses.
A recent review found that emergency departments now record rising CHS diagnoses, especially among younger adults who use high-potency cannabis frequently. They warned that patients often dismiss persistent vomiting as food poisoning or anxiety. In their view, recognising CHS early helps people link terrifying symptoms to heavy cannabis use. That professional warning has helped push this once obscure syndrome into mainstream discussion. For psychiatrists, CHS is a wake-up call. A drug widely promoted as an anti-nausea remedy can, in some users, trigger relentless vomiting that only stops when cannabis use ends. That contradiction helps challenge simplistic claims that one substance is inherently safe and the other is not.
What smoking weed does to your heart
For many people, the truly shocking news involves the heart, not the stomach. At a 2025 scientific meeting of the American College of Cardiology, researchers presented a retrospective study. It included more than 4.6 million adults younger than 50. Cannabis users in this group were over 6 times more likely to suffer a heart attack than non-users. The same analysis found a 4-fold increase in ischemic stroke and a 2-fold increase in heart failure. It also showed a sharply higher risk of serious cardiovascular events, including heart attack or stroke. Study leader Dr Ibrahim Kamel said that clinicians should always ask about cannabis use when they assess cardiovascular risk. A separate meta-analysis of 12 studies, also presented by the American College of Cardiology, examined active cannabis users.
Those users were about 1.5 times as likely to have a heart attack as people who did not use cannabis. A global review from researchers at the University of Toulouse suggested that cannabis use may double the risk of death from cardiovascular disease. The same review reported a 20% increase in stroke risk among cannabis users. Cardiologists suspect several mechanisms, including increased heart rate and damage to the blood vessel lining. These findings directly challenge the casual idea that a joint offers a harmless way to relax after work. Importantly, the researchers controlled for factors like tobacco use and obesity where possible. That approach strengthens the signal that cannabis itself may drive extra cardiovascular risk. Experts also stress that many participants were still relatively young adults with otherwise good health. Seeing heart attacks in people under 50 makes clinicians pay very close attention.
Lungs, blood vessels, and the myth of a “gentler” smoke
Many people argue that cannabis smoke must be less harmful than tobacco smoke. Heart surgeon Dr Jeremy London gives a blunt answer. He tells his patients that lungs have one simple function, which is to move air in and out efficiently, and that anything else is potentially harmful. In his operating theatre, he has described operating on multiple patients who smoked marijuana regularly, whose lungs looked totally black, as if they had worked in a coal mine, despite never smoking cigarettes. Those patients had such severe blockages that they needed to undergo bypass surgery.
Research backs his concern. The American Lung Association cautions the public against smoking marijuana because of the risk of damage to the lungs. The United States Centers for Disease Control and Prevention similarly warns that smoked cannabis can harm lung tissues and cause scarring and damage to small blood vessels. These harms matter for mental health as well, because low oxygen levels and chronic inflammation affect brain function and mood. Psychiatrists increasingly remind patients that inhaling any burning plant material, whether tobacco or cannabis, pushes toxins, fine particles, and carcinogens directly into delicate lung tissue and the bloodstream. This is markedly different from an occasional prescription medication used under careful supervision.
Alcohol’s damage runs deeper than most drinkers realise
None of this turns alcohol into the “good” substance in the alcohol vs. cannabis debate. Excessive drinking remains one of the most important preventable causes of disease worldwide. The Centers for Disease Control and Prevention report that excessive alcohol use is a leading preventable cause of death in the United States, contributing to around 178,000 deaths every year. The World Health Organization goes further, stating that when it comes to alcohol, there is no safe amount that does not affect health. Even light drinking increases the risk of several cancers, including breast and colorectal cancer.
Recent research in the journal Neurology found that people who consumed eight or more alcoholic drinks per week had greater brain damage associated with cognitive decline and Alzheimer’s disease, and died younger than lighter drinkers. The National Institute on Alcohol Abuse and Alcoholism describes alcohol as a leading cause of illness and early death and warns of health risks even at low consumption levels. For psychiatrists, alcohol still causes more social harm, violence, self-harm, and dependence globally than cannabis. However, the fact that alcohol carries enormous risk does not excuse the emerging cardiovascular and gastrointestinal harms linked to heavy cannabis use. Both substances can take a serious toll, just in different ways and at different doses.
Addiction and dependence: which drug hooks more people?
Patients sometimes insist that cannabis cannot be addictive. Official data says otherwise. The CDC estimates that approximately 3 in 10 people who use cannabis have cannabis use disorder. The risk is higher for those who start in adolescence or use daily. The American Psychiatric Association notes that studies indicate that around 9% of users become dependent on cannabis, and that the figure rises significantly among daily users and young people who start early. Withdrawal can involve irritability, sleep problems, and strong cravings, which sometimes surprise users who believed they could stop easily.
Alcohol dependence remains even more common and often more destructive. The National Institute on Alcohol Abuse and Alcoholism describes alcohol as a leading cause of illness and early death, highlighting that alcohol-related emergency visits and deaths keep rising. Many people underestimate how quickly heavy or frequent drinking can spiral into alcohol use disorder, with job loss, family breakdown, and legal problems following. From a psychiatrist’s perspective, both alcohol and cannabis can create powerful psychological habits. However, alcohol usually causes more dramatic withdrawal syndromes and more immediate external harm, while cannabis dependence can quietly undermine motivation, memory, and emotional stability over time.
Mental health consequences through a psychiatrist’s eyes
Psychiatrists worry deeply about how both substances affect the brain. The American Psychiatric Association notes that cannabis can have short and long-term effects on the brain, including attention and memory problems, and that there is evidence that cannabis may worsen or hasten the start of psychiatric illness, particularly in young adults. Research shows higher rates of psychotic disorders among people who use high-potency cannabis frequently, especially if they have a family history of psychosis. For some patients with depression, cannabis use is linked to increased suicidal thoughts and attempts, which adds another layer of concern.
Alcohol also damages mental health, but in slightly different ways. It can worsen depression and anxiety, while heavy drinking increases the risk of self-harm, domestic violence, and accidents. The National Institute on Alcohol Abuse and Alcoholism reports that alcohol contributes to millions of emergency visits for both physical and mental health crises. From a psychiatrist’s perspective, heavy cannabis use raises more alarms about psychosis and motivational decline, whereas heavy alcohol use raises more alarms about impulsive harm and long-term cognitive decline. Neither substance supports stable mood, clear thinking, or good judgment when used heavily or as self-medication.
Weighing everyday risks: dose, frequency, and personal vulnerability
The real-world alcohol vs. cannabis comparison depends heavily on dose, frequency, and individual vulnerability. A person who drinks one small beer once a week carries a different risk profile than someone who binge-drinks several nights. Likewise, someone who takes a prescribed cannabis-based medicine under supervision is different from a young adult vaping high-THC concentrates daily. The Centers for Disease Control and Prevention notes that the risk of developing cannabis use disorder is greater for people who begin to use it before age 18. High-potency products and daily use increase both CHS and psychosis risks.
Alcohol risk also rises with total intake and binge episodes. The World Health Organization emphasises that risks start from the first drop, and that the type of drink matters far less than the amount consumed. For some people, genetic factors, existing heart disease, or trauma histories make either substance especially dangerous. Psychiatrists, therefore, try to move conversations away from blanket statements and toward personal risk. A person with a family history of psychosis may face great danger from regular cannabis, while a person with liver disease or breast cancer risk may need to avoid alcohol completely.
How psychiatrists now talk about alcohol versus cannabis
When patients ask which substance is better, many psychiatrists now answer with careful nuance and clear warnings. The American College of Cardiology recently reported that people who use cannabis are more likely to suffer a heart attack than people who do not use the drug, even among younger and otherwise healthy adults. At the same time, the World Health Organization reminds the public that there is no safe amount of alcohol that leaves health untouched. These messages may sound strict, but they help people see that both substances carry measurable and sometimes serious risks.
A balanced view recognises that alcohol currently causes more deaths, cancers, and social harm worldwide, while cannabis now shows clearer links to heart attacks, psychosis, CHS, and dependence, particularly in younger heavy users. Psychiatrists, therefore, encourage patients to ask a different question. Instead of choosing sides in the alcohol vs. cannabis debates, they can ask how to reduce total exposure to both. That might involve cutting down drinking days, avoiding high-potency cannabis products, choosing non-smoking routes when medically appropriate, or seeking help for any use that feels difficult to control. In clinical practice, the safest long-term strategy usually involves fewer intoxicants, honest conversations with health professionals, and solid support for underlying anxiety, pain, or trauma that people often try to treat on their own.