I’m a Psychiatrist. Here’s What I Want People to Know About Marijuana and Mental Health

Guest article by Jody Ryan, M.D., Chief Medical Officer at WellPower

Key Takeaways

I’m an addiction-certified psychiatrist, and I also happen to be WellPower’s chief medical officer. Here’s what I want every person, parent and provider to know about marijuana and mental health:

Cannabis is not always harmless. Regular use carries real risks, especially for young people and those with a family history of mental illness.
Potency matters. Today’s products are often far stronger than the cannabis of past decades.
Early use increases harm. The adolescent and young adult brain is particularly vulnerable.
If you notice changes, stop and seek help. Symptoms of increased anxiety, mood instability, social withdrawal, or school or work performance should be taken seriously. Cessation is strongly recommended while you seek professional medical guidance.

Marijuana and Mental Health

A topic we hear a lot about in the mental health world is marijuana, also known by many other names like cannabis and weed (note that this is different from CBD). In fact, I work with my own patients a lot around this topic – both the impact on mental health in general and on their mental health symptoms in particular.

In Colorado, marijuana legalization is more than a decade old. And as people drink less alcohol these days – this is especially true among Gen Z – cannabis is a common alternative. So, I thought I would take a moment to share with you what we know at this point in time about the impact of marijuana on mental health. (My focus here is specifically on recreational use. The prescribed use of cannabis under medical supervision for things like pain relief is a slightly different area with other implications.)

Just a note before we begin: What follows is all based on the most current research on cannabis and mental health. Because we in the medical community are learning more and more every day about this topic, this guidance might continue to evolve in the coming years, and even months. And this is a good thing – when we learn more, we understand things differently, and that might mean that we make different kinds of recommendations and decisions than in the recent past. When it’s done well, scientifically-inspired change gets us closer to understanding the way things truly work.

Cannabis and Psychosis: A Risk We Can’t Ignore

While cannabis is often perceived as “natural,” “safe” or “therapeutic,” emerging research highlights a more complicated picture. For many people, the effects of marijuana really are quite benign – they can use the substance without significant near- or longer-term impact. However, for many other people, the effects of marijuana are not harmless. Among this group, regular use – especially daily or near daily use, high‑ potency‑ products, or use beginning in adolescence – can significantly increase mental health risks.

Among the most well documented, but least understood, is the association between regular cannabis use and psychosis, or the experience of not being able to tell what’s real and what’s not. Large population studies now indicate that regular cannabis use increases the likelihood of developing psychotic symptoms and schizophrenia-spectrum disorders. But there is some nuance here.

Two main factors influence the risk of psychosis following cannabis use.

Genetic predisposition. For individuals who are already vulnerable – particularly young people, men and those with a family history of psychosis – the risk is significantly higher. In fact, some studies estimate that 15–20% of schizophrenia cases in young men may be attributable to cannabis use disorder if the relationship is causal. (Note: this doesn’t mean that 20% of people who use cannabis will develop schizophrenia, but that among the people who do experience schizophrenia, up to 20% may be able to trace onset back to marijuana use.)

Dose. The more frequently a person uses marijuana and the higher the THC concentration (the “active ingredient” in marijuana that produces the feeling of a high), the higher the risk. High potency products, concentrates and dabs – widely available in today’s market – exacerbate that risk even further. In the medical and public health communities, we call this “dose dependent” – the more of a substance, the greater the effect.

Before we continue I do want to emphasize again: cannabis does not cause psychosis in everyone, nor does every person who uses marijuana experience long-term effects. Instead, cannabis acts as a risk amplifier that can accelerate or trigger psychosis in those already predisposed. The amount of substance used and the length of time over which it’s used turn the dial up on this risk even more.

Marijuana and Depression, Anxiety and Suicidality

Another common belief is that cannabis helps people relax or manage their emotions. Again, for many people, this can actually be true: some individuals do experience short term calming effects. However, for many others, regular cannabis use is strongly associated with higher rates of depression, increased anxiety over time and elevated risk of suicidal ideation or attempts. This is especially common among adolescents.

Unsurprisingly, this can lead to a challenging cycle: someone uses marijuana to cope with stress or sadness, but over time the symptoms worsen, leading them to use more frequently, which in turn makes their symptoms even worse.

At WellPower, we see this pattern frequently in both youth and adults who are experiencing mental health conditions. For those already navigating the complexities of mental health symptoms, as well as identity, relationships, academic and general life pressures, regular marijuana use can make an already difficult experience even more challenging.

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Cannabis Use Disorder: More Common Than Many Realize

Regular cannabis use can also lead to dependence. Research shows that:

1 in 10 people who ever use cannabis will develop Cannabis Use Disorder (CUD), and
That number rises to 1 in 3 among daily or near daily users. Remember that dose dependency from the risk of psychosis? That same principle applies with CUD, as well.

As with other addictions, withdrawal symptoms – including irritability, insomnia, anxiety, low mood and reduced appetite – are real and can make quitting extremely difficult.

For many, cannabis does not fit the stereotype of an addictive substance. But the clinical reality based on data is clear: cannabis can be addictive, and dependence is increasingly common in states like Colorado where accessibility is high (no pun intended).

Marijuana’s Impact on Learning, Memory and Attention

Cannabis affects the brain’s ability to learn, remember and focus. Studies show that regular marijuana use is associated with significant impairments in memory, attention and executive functioning, which is the brain’s management system.

These effects are strongest in individuals who begin using before age 25, during a critical stage of brain development. You might recall that the brain continues to develop rapidly up to a person’s mid-20s. During this time, environmental factors can have outsized effects on how our brains function throughout the rest of adulthood. Some cognitive impairments from cannabis use are relatively temporary and improve with abstinence, but long-term heavy use can lead to persistent lifelong changes.

For adolescents and young adults – particularly those still in school – regular cannabis use is linked to:

Lower academic performance
Higher dropout rates
Reduced work-related functioning in adulthood

In other words, early cannabis use may shape not only cognitive health but long- term life opportunities. And no, this isn’t just due to stereotypes about laziness and lack of motivation among people who use marijuana – it comes down to actual, physical changes in the brain.

Physical Health Risks: Beyond the Brain

Going beyond the brain now, the physical health effects of regular cannabis use are also real and measurable. Here are a few:

Cardiovascular (Heart) Effects

Multiple large‑scale analyses published in 2025 show significant increases in cardiovascular risks among cannabis users, even in populations without traditional risk factors.

Key findings include:

6-times higher risk of myocardial infarction (heart attack) in adults under age 50 who use cannabis and don’t have other related health concerns.
4-times higher risk of ischemic stroke (a stroke that occurs due to lack of blood to the brain).
2-times higher risk of heart failure.

Pulmonary (Lung) Effects

Though smoking marijuana is often perceived as safer than smoking tobacco, inhaled cannabis can cause:

Chronic cough
Wheezing
Bronchitis‑like symptoms

This is because inhalation – especially deep inhalation or prolonged breath holding – delivers strong concentrations of irritants and carcinogens into the lungs.

Cannabinoid Hyperemesis Syndrome (CHS)

An increasingly recognized condition, cannabinoid hyperemesis syndrome (CHS) involves recurrent severe nausea and vomiting in long‑term, frequent users. Symptoms often improve temporarily with hot showers but resolve only with stopping cannabis use.

Driving, Daily Functioning and Quality of Life

I would be remiss if I didn’t at least mention a few other important impacts of marijuana, which could each be the subject of articles unto themselves. Cannabis use impairs reaction time and coordination, increasing the risk of motor vehicle accidents. And depending on how it’s used, cannabis can also interfere with relationships, work performance and school performance – all significant factors that shape overall well‑being throughout our lives. I encourage you to follow each of these links for more information from reputable sources about these areas.

How to Get Help with Marijuana Use

If you or someone you love is struggling with marijuana use or experiencing mental health symptoms, my team at WellPower is here to help. Just like with any other mental health or substance use concern, our approach is not judgment – it’s education, compassion and support, all with individualized care that addresses each person’s unique needs and goals.

Please always feel free to give us a call at (303) 504-7900, or find out more about our approach to mental health services here. We gladly welcome Medicaid members, and we accept a range of Medicare and commercial insurance plans.

For immediate, round-the-clock support – especially outside of WellPower’s open hours – you can call, text or chat 988, the Mental Health Lifeline. In Colorado, you can also visit a walk-in center for immediate, in-person help in a crisis. Denver’s 24/7/365 walk-in center (operated by WellPower) is at 4353 E. Colfax Ave. Other locations are listed here.

Dr. Jody Ryan is board certified in Psychiatry (FRCPSC) and Addiction Medicine, as well as ABAM-certified in Addiction Medicine from the American Board of Addiction Medicine. He currently serves as WellPower’s chief medical officer and continues to see patients while overseeing the organization’s medical and psychiatry programs.

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