Bipolar disorder and weed: how experts say they go together

Cannabis use can harm those with bipolar disorder, a new study finds. But other experts have doubts

December 19, 2019
A person holds a glass bowl and lights up
Marijuana is a go-to recreational drug for some, but it could be harming those with bipolar disorder [Sharon McCutcheon | Unsplash]

Patients with bipolar disorder who use cannabis have an earlier onset of mental illness, a lifetime of more severe symptoms and more suicide attempts, a new study finds.

The researchers, who did not respond to an interview request, found that people with bipolar disorder who use cannabis are most likely to be single males having a lifetime of psychotic symptoms, have a history of tobacco, alcohol, and psychoactive use, and have attempted suicide. But other researchers who study marijuana and bipolar disorder have doubts. 

“What [the researchers] are saying is that people with bipolar disorder have a number of negative outcomes associated with cannabis use. I think that’s true in general,” said Staci Gruber, an associate professor who studies cannabis in people with mental illnesses at Harvard University. She was not involved in the study. 

The researchers, based out of various institutions in Brazil, sifted through 2,918 bipolar-cannabis articles down to find 53. The researchers noted, among other things, the sample size, age, gender, ethnicity, prevalence of cannabis use, type of bipolar disorder, age at onset of bipolar disorder and lifetime suicide attempts of the subjects included in their studies. The researchers then analyzed these to pull out commonalities. 

Those with bipolar disorder were also significantly more likely to abuse cannabis to the point of having a disorder than those without the mental illness. According to the study, 24% of people with bipolar disorder used cannabis or abused it to the point of harming their lives. The researchers did not respond to requests for further comment on their study. 

Bipolar disorder is a mental condition involving unusual changes in energy, mood and ability to function in daily life. Approximately 4.4% of Americans — or 14.5 million people in the United States — experience bipolar disorder. 

The quarter of bipolar patients who use cannabis, according to the study, could be doing so at the risk of their mental health and lives. 

However, Gruber and other marijuana and bipolar disorder researchers are skeptical of the Brazilian study’s results. Gruber says the study has unaddressed limitations that make it difficult to discern precisely how marijuana affects bipolar patients. 

To create comprehensive studies, also called systematic reviews or meta-analyses, researchers assess numerous scientific papers to tease out broader trends. The findings are generally considered robust because they average the points of numerous peer reviewed papers. 

But Gruber says the study should have disentangled why people use marijuana. Some bipolar patients may use cannabis recreationally to induce an altered emotional or mental state. Others might pragmatically use marijuana to alleviate depressive episodes or calm manic periods. 

Gruber also notes that bipolar patients are likely to use more than one substance at once, meaning they could be consuming marijuana as well as alcohol and other drugs. To say cannabis alone causes negative outcomes skews the context in which the drug was used. 

Trine Vik Lagerberg, a clinical psychologist from the Oslo University Hospital in Norway researching cannabis and bipolar disorder, also sees limitations in the study. She has read high-quality studies indicating correlation between an earlier onset of bipolar disorder symptoms and cannabis use, but she’s more skeptical that marijuana is the sole cause. 

“I am not fully convinced that this relationship is independent from other factors,” Lagerberg says. “With this, I mean that cannabis users may have some characteristics that leave them at greater risk for suicide which does not have to do with the cannabis use itself.”

In other words, here’s what hobbles the efficacy of this study: the failure to differentiate the reason for marijuana use among bipolar patients and the types of marijuana used, as well as the generalized correlation between cannabis use and suicide in bipolar disorder.

With Luxembourg, Mexico, and other countries poised to legalize marijuana, cannabis use is becoming a common pastime in many nations. Comprehensive studies like this one provide stronger support for how marijuana affects people with bipolar disorder, but Gruber notes a more nuanced take on the research is needed to support definitive claims. 

“Why are they using and what are they using? […] Did cannabis use precede the bipolar disorder, or did it follow?” Gruber says. “All these things are important.”

About the Author

M.K. Manoylov

MK Manoylov likes covering trees, the environment, microbes, and all things bugs. MK was the former opinion editor for The Red & Black newspaper and moved to Brooklyn to pursue science journalism. When not writing, you can find MK editing videos or drawing comics.



P. A. Sam says:

Well thought out analysis. Also, consider dosages of Cannabis as well as type, and reason for use. How much is helpful for depression and how much drives mania, and dopamine surges. So interesting. It can be difficult to know if Cannabis was a precursor of, or, as a result of having bipolar symptoms. Bipolar in children may show different and/or milder symptoms and therefore be difficult to recognize. What is also interesting is the theory of inflammation and gut health. For instance I know a family where the mother has Crohn’s and the son has Bipolar. Good luck on the further research. So many people with bipolar use Cannabis, that it would be helpful to know what can be useful, if anything, and what is detrimental. Thank you.

Michelle says:

P.A. Sam,
I wonder if there is a connection with Crohn’s and Bipolar. My ex and his brother have Bipolar and his mother has Crohn’s. A certain strain of weed set off his first panic attack before diagnosis. Other strains were ok. I do not know how it would affect his meds at this point however.

JB says:

Currently experiencing this dilemma now. Seeing a psychiatrist next week to discuss. Thanks for posting.

Diana Martin says:

Sorry, but bullshit.

Jesse J Johnson says:

My daughter is diagnosed as Bipolar and has a state medical card for Cannabis has experienced severe mental illness. She sees things coming out of the walls & voices talking to her. Recently she thought an intruder was breaking into her apartment. She barricaded herself and her two children in one of her upstairs bedrooms. She dialed 911 the police for help. She says the voices told her to get the children outside for safety, unfortunately, this was all an illusion in her own mind. The police broke down the door just in time to save the oldest child from being thrown out of the window. The first child was rushed to the hospital, which later was ok. The children were removed & my daughter is in jail facing all the charges that would come with this type of incident. This type of mental illness never manifested in her until she started to use Cannabis with her Bipolar condition. I can now say, she is taking her normal medication that helps with being bipolar, and it is pleasant talking to a normal person for once. Child services were notified by us, the parents about her condition and they chose not to do anything about it, until this incident happened.

Emile Lupichuk says:

Well this is nonsense.
Interesting replies but the experiment in finding out if a person became worse with the use of pot for bipolar seems to be trying too much to show that pot is bad and this kind of thing has been done to death.
It is part of the reason that people like myself could never get a doctor to prescribe pot for the condition because they have been scared for decades over the pot evil mantra that doctors pull out whenever you broach the subject afraid that big brother will take their licence away from them.
Let’s really look into the problem of people using pot to help them with the highs and lows of using THC Sativa or CBD Indica for their current conditions and don’t take people that are addicted to pot because that brings up a whole set of problems that any addiction will bring and is a self fulfilling prophesy that ends with you saying pot bad.
Try getting new patients that did not use pot prior to the experiment and have them take the right kind of pot to start in the right dosage.
Just don’t treat them like imbeciles or children that need you to take away their right to independent thought.
That would be an actual study instead of getting people already using for a while who just happen to be bi polar.

LEE MANA says:

Cannibas is a cover up and may temporary work for one person, as it may not work for the other, everyone is different. Unfortunately cannibas was marketed as a cure all, which it is not If I knew that 70% of the people who used cannibas would increase the chances of delisions and panic attacks, or make your mind think your pain is worse, (result of addiction) I would stay away, even though it may give you a calm for the first use. These chemicals add up and your messing with the brain. Quite scarry. There is always a root of the problem, it could be PTSD, or it could be an abusive relationship, and you have to to work hard to climb out above this illness and make changes in your life. Hopefully you have people in your life to help you through this difficult time. Using cannibas for a temporary relief is insulting the diagnoses because it is chemicals and adding to the illness, messing with the brain. There is a fine line to controlling this illness, stay with a good medical Doctor who does not encourage cannibas, and start with minimum doses of perscription. I see many bipolar people who become medicated zombies. Again, everyone is different. But cannibas is not the answer. It will not get you better in the long term.

Jacqueline Oner says:

My questions were not answered. Particularly, does a bi polar son who is addicted
to pot from age 9, smoking heavily everyday lose his ability to love, to care, to be
compassionate, to honor his mother who raised him singly and never abused him
or acted hostily towards him. Does the affectionate part of the mind stop growing
or is it completely lost in the growing process?

E J says:

I smoke pot when I get into my manic episodes.

It is the ONLY thing that calms me down and turns the 1000 gerbils on their wheels into only a cymbal monkey.

It’s wonderful. It calms me down and I’ve never had any negative side effects because of it. I feel what I know is normal when I smoke during these times.

I also never respond to internet articles, so to add that I truly am having a manic episode! :D

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