Does Marijuana Help or Hurt People With Bipolar Disorder?

by HelloMD

Cannabis is used to manage so many conditions that it's only natural to wonder if it can help people with bipolar disorder. The answer, however, is still unclear. While some people have said it helps them manage their bipolar disorder symptoms, research suggests that cannabis use can make certain symptoms worsen. The question then becomes: What does this mean for people diagnosed with bipolar disorder?


After Consuming Cannabis, Patients With Bipolar Disorder Have More Mania & Depression

In 2015, the U.K.'s Lancaster University conducted a study that concluded that cannabis use exacerbates or worsens some bipolar symptoms. In particular, it claimed that depression and mania increased due to the consumption of cannabis. This finding has surprised many people, in light of the fact that some doctors have recommended medical marijuana to their patients with bipolar disorder due to the plant’s ability to help support cognitive functioning.

During the study, 24 people with bipolar disorder consumed cannabis at least three times per week and then recorded their mood in a diary. Called the experience sampling method, or ESM, its intended to reduce the risk of memory bias, which can happen when patients report their mood at a later date.


Bipolar Disorder Patients Took Cannabis When Experiencing Positive Feelings

Before the researchers drew any conclusions, they analyzed the participants’ diary entries, taking into account age, sex and the use of other types of drugs. The results showed that the use of cannabis often led to more positive feelings, but were accompanied by more manic and depressive symptoms.

It should be noted that the bipolar disorder study participants used marijuana when they were experiencing positive emotions, not right after a depressive or manic episode. This suggests that their cannabis consumption wasn’t due to any self-medicating type of behavior.

Marijuana Study on Folks With Bipolar Disorder Is Flawed

As with a number of studies, people should take the findings with a grain of salt, because there are some possible flaws in this study. For example, the sample size of this study was very small: only 24 people. As well, there was a lack of diversity among the participants; they were all from the U.K., so there's no telling if their background possibly influenced the findings.

In addition, the people who participated in the study weren’t in the middle of a manic or depressive episode. It's possible the findings could be different if they were.

Also, those who were studied were only able to report their cannabis ingestion methods with the use of three categories: resin, skunk and grass. The study didn’t take into account the possibility that different doses and methods of cannabis delivery could have different results.


Another possible problem is that the researchers involved the study may have interpreted the diary entries with a subjective lens—meaning, they weren’t objective. Their own biases could have influenced their conclusions.

Lastly, this study had no control group. This makes it impossible to know if people who don’t have bipolar disorder could have the same—or different—results when consuming cannabis.

The Jury’s Still Out on Whether Marijuana Is Bad for Bipolar Disorder

Considering that this study's findings may be skewed and therefore inaccurate, we can’t know for sure whether marijuana hurts—or helps—people with bipolar disorder. In the end, people who’ve noticed positive effects with cannabis on bipolar disorder symptoms should continue using it. Those who’ve noticed no change or negative effects when consuming marijuana can move on to other options for reducing symptoms of bipolar disorder.

In the meantime, anyone interested in the relationship between bipolar disorder and marijuana use can look forward to seeing more definitive answers once a larger, more accurate study is completed.

Photo credit: Bill Strain

If you’re new to cannabis and want to learn more, take a look at our Cannabis 101 post. HelloMD can help you get your medical marijuana recommendation; it's easy, private and 100% online.