Cannabis—Too Good to Be True?

There is mounting evidence which links cannabis use to mental health issues.

Posted Dec 02, 2019

 Torben Hansen/Wikimedia, used with permission
Marijuana joint
Source: Torben Hansen/Wikimedia, used with permission

In the past few years, I have become increasingly alarmed at the discrepancy between the hype about the merits and benevolence of marijuana use versus what I see in my psychotherapy practice.

Marijuana has become so ubiquitous and normalized that many of my patients don't even mention their marijuana use when I ask them routine questions about their drug use. They will talk about how much alcohol they consume or the Xanax they take for anxiety or the various uppers they consumed at a party over the weekend—but the joint they smoke at night to relax barely registers as a drug. 

I’ve learned that I have to ask specifically about marijuana. When I do, suddenly stories of cannabis use-gone-awry pour out. These narratives clash with the happy public image of weed as not being addictive, not being overdose-able, and curing everything from depression to cancer to doggie arthritis.

When my patients recount their bad experiences, they often tend to minimize or even apologize for them. One young woman said with a shrug, “My family just doesn’t have the right genes for weed. I stopped smoking when I had a series of disturbingly bad trips, where I lost all control over my bodily functions. My brother has it worse, though. He smokes every day, dropped out of college, and now he can’t hold a job.”

Marijuana is highly politicized. Its decriminalization and legalization were an important social justice victory since a hugely disproportionate number of those convicted for crimes involving marijuana are people of color. In addition, there is also much hope that cannabis may help alleviate the opium crisis. Within this political context, many people feel social pressure not to question the safety of cannabis and to blame their negative experiences on an allergic reaction, a genetic incompatibility, or some other circumstance.

I, too, initially viewed my patients’ stories as purely anecdotal, isolated incidents where other factors were involved in the negative outcome. For example, the distressed mother of a 16-year-old boy called to tell me that her son had been hospitalized. He had been a regular cannabis user when he, for no apparent reason, boarded a train.

Many hours later and several hundred miles from home, he got picked up by the police. He didn’t know who he was, where he was, or why he had gotten on the train in the first place (fortunately, he did have his ID with him). Although his mother was sure that he had only smoked weed, at the time, I couldn't imagine that it could have caused such a severe psychotic break, and I assumed that he must have suffered an overdose involving other psychoactive substances.

But in recent years, a steadily growing number of studies link cannabis use to an increased likelihood to develop psychosis, schizophrenia, paranoia, and higher incidences of violence. Other statistics suggest that approximately one out of nine marijuana users will become addicted, rising to about 17 percent in those who start using in their teens. These numbers might not be enough to ring alarm bells, but given how many Americans have become regular users of cannabis, it is quite possible that we may have a hidden epidemic on our hands.

Still, the general consensus is that marijuana is safe for the vast majority of users. And yet the picture might look very different if other criteria than psychotic breaks are applied to measure its safety, such as:

  • Does marijuana affect your ability to establish and maintain healthy relationships?
  • Does it make you more anxious or depressed? Less empathic? Angrier?
  • Does marijuana negatively affect your productivity?
  • Do you have a social life outside of your marijuana-smoking circle of friends?

The answers to these questions will, of course, depend heavily on the frequency of use and the potency. Cannabis is a complex plant. For example, CBD (one of the non-psychoactive substances produced by the plant) has been shown to reduce anxiety and depression, whereas THC (the main psychoactive compound in marijuana) can actually increase anxiety and depression. Similarly, cannabis has proven to be effective in treating nausea, particularly with patients undergoing chemotherapy, but at high dosages and with habitual use, it also can induce cyclical vomiting (cannabis hyperemesis).  

Psychologically speaking, cannabis is an amplifier, meaning that intent and motivation matter. Particularly for developing young brains, high-potency THC can have a highly destabilizing effect. For example, a teenager’s developmentally appropriate existential angst can quickly morph into a full-blown panic attack under the influence of THC. 

Parents should be aware that the marijuana their children have access to today is not the drug of the giggles and munchies they grew up with anymore. In the 1980s, pot generally averaged a THC content of no more than 5 percent. According to one study, in just the last 10 years, the average potency of commercially available cannabis almost doubled, from an 8.9 percent THC concentration to 17.1 percent, with much higher concentrations easily available on the street and in stores. 

More research is needed on the effects of long-term, high-potency marijuana use, particularly in teens and young adults. And maybe, we will find that more regulations are required, such as capping the potency of cannabis products available today.

The last thing I’d want, though, is the pendulum to swing back to demonizing and criminalizing cannabis. But the current hype around marijuana trivializes it to a dangerous degree. Products from cannabis-infused gummies, chocolates, sodas, and beers, to weed-cations and an ever-growing array of exotic weed strains with irreverent names, contribute to this narrative. 

A more balanced approach is needed, where the focus is as much on marijuana’s medicinal and recreational potential as it is on its capacity to cause serious and lasting harm.  

Marijuana is, at times, referred to as a “magic” plant. And as we all learned as children, from fairy tales to Harry Potter, there is no such thing as only “good” magic. If not handled carefully and responsibly, any kind of magic can very quickly get out of hand. 


Berenson,, A. (2019). Tell Your Children:  The Truth About Marijuana, Mental Illness, and Violence. Free Press, NY, NY 10020.

Chandra S, et al.. New trends in cannabis potency in USA and Europe during the last decade (2008-2017). European Archives of Psychiatry and Clinical Neuroscience. (May 2019)

Mustonen A, et al.. Adolescent Cannabis Use, Baseline Prodromal Syndromes, and the Risk of Psychosis. British Journal of Psychiatry. Volume 212, April 2018, pp. 227-233. 

National Institute on Drug Abuse (2019). Is Marijuana Addictive? 

The National Academies of Sciences, Engineering and Medicine, 2017: The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research.