Cannabis has long had a reputation for helping people relax, but recent research has shown that it can have a negative impact on mental health. Therefore, it is understandable that you have questions.
Cannabis – also referred to as weed, weed, or marijuana – is legal in 23 states, making it more accessible than ever. It’s also worth noting that many pharmacies sell cannabis strains that are marketed to help with certain mental conditions, including anxiety and depression. How should we reconcile this conflicting information? Here’s a breakdown of the data, along with how mental health experts advise their patients about cannabis use.
What does the data on mental health and cannabis use say?
A few studies have been done on the impact of cannabis on mental health, and the results are mixed. Below are some of the most important:
A study of more than 6 million Danes published in JAMA Psychiatry found in May that people with cannabis use disorder (meaning they can’t stop using marijuana) have a higher risk of psychotic and nonpsychotic depression and bipolar disorder. The researchers found that people with cannabis use disorders had nearly twice the risk of developing depression and up to three times the risk of bipolar disorder.
A scientific review published in JAMA Psychiatry in 2016 found that people who use marijuana are more likely to develop temporary psychosis, as well as long-term mental disorders such as schizophrenia. The link between schizophrenia and cannabis use was stronger in people who started using cannabis at a young age and continued to use it more often.
A 2021 review published in Boundaries in psychiatry notes that people with serious mental illness use cannabis “much higher than the general population”. The rates of lifetime cannabis use for patients with schizophrenia, major depressive disorder or bipolar disorder are 80%, 17% and 24%, respectively, the review found. The researchers also found that about 40% of patients with schizophrenia and 20% of patients with major depressive disorder or bipolar disorder are also diagnosed with cannabis use disorder.
On the bright side, a 2020 research article published in BMC Psychiatry concluded that there is “encouraging, if embryonic” (i.e. early stage) evidence for the use of medical cannabis to treat a range of psychiatric disorders. The researchers noted that there is “tentative support” for using CBD to treat social anxiety; there are also case studies suggesting that cannabis can help with sleep and post-traumatic stress disorder. The researchers pointed out that cannabis can also help with ADHD.
Research has shown that heavy marijuana use during the teenage and young adult years can increase the risk of developing schizophrenia and psychosis. There is also some evidence that regular marijuana use may accelerate the onset of symptoms of mood disorders such as bipolar disorder and major depression, along with anxiety disorders, especially in younger people.
The National Alliance on Mental Illness (NAMI) notes that while some states have legalized marijuana, it is still classified as a Schedule I drug, making it difficult to study. This has limited “robust scientific research,” NAMI says.
Mental health experts say the reality of cannabis use is complicated
Much of the data on marijuana use and mental health focuses on people who are heavy cannabis users, making it difficult to say for sure how sporadic marijuana use will affect people, Hillary Ammon, a clinical psychologist at the Center for Anxiety & Women’s Emotional Wellness, said. tells Yahoo Life. It’s also hard to say that heavy marijuana use causes certain psychological symptoms – it may simply be that people with certain mental illnesses are more likely to turn to marijuana.
“Studies show that frequent cannabis users consistently have a higher prevalence of anxiety and depressive disorders,” Dr. Zachary Kelm, clinical assistant professor in the department of psychiatry and behavioral health at The Ohio State University Wexner Medical Center, told Yahoo Life. “At the same time, people with depression and anxiety use cannabis more often. It is not clear whether cannabis use causes anxiety or depression, but there is clearly a connection.”
However, some people feel that using cannabis helps them relax, says Ammon. “I work with many clients with anxiety who have reported that smoking cannabis helps them feel calmer and slow down or quiet spiraling thoughts. Others report that it helps them sleep better at night,” she says. Ammon says she has also worked with patients with ADHD who say some strains of cannabis help them focus.
“Such anecdotal reports are hard to ignore,” says Dr. David Nathan, a psychiatrist at Penn Medicine and Princeton House Behavioral Health, told Yahoo Life. But Nathan says there are caveats. “While people often feel comfortable for the first few hours after consuming cannabis, they may feel a bit more anxious or moody after cannabis is out of their system,” he says. “Frequent use of cannabis may amplify this type of ‘rebound’ and consumers may not link cannabis use to later negative effects.”
Developing a cannabis use disorder is also a possibility with marijuana use, says Kelm. “Addiction, or a cannabis use disorder, develops in about 10% of users,” he says. “Initiating cannabis at a younger age is a risk factor for developing problematic cannabis use, which can lead to cravings, tolerance, withdrawal, difficulty reducing use, difficulty fulfilling important role obligations at work, school or home, use in physically hazardous situations, and limitations in social or occupational functioning.”
What do experts recommend?
Experts generally recommend that people with mental illness try to avoid cannabis, especially if they are related to certain mental disorders. “I almost always recommend that people with a personal history of schizophrenia or another psychotic disorder avoid THC-containing cannabis completely,” says Nathan. “Even people wh
o have close relatives with psychotic disorders should think twice and be very careful before using cannabis.”
Ammon also urges caution. “Cannabis use can be helpful in the short term, but it’s often just that: a temporary fix,” she says. “It can help you feel calm or quiet thoughts for a moment, but those problems often come back.”
Kelm also advises against its use. “There is currently no strong scientific evidence that cannabis is a beneficial treatment for any mental illness,” he says. “Cannabis use has been linked to both depression and anxiety, but it’s not clear whether it causes these conditions.”
That said, Kelm says he’s open to patients who say cannabis use benefits their mental health. “We continue to work towards achieving their goals,” he says. “I have also informed patients that I will keep abreast of the scientific literature on cannabis and mental health as it evolves. We will hopefully gain a better understanding of how cannabis, especially THC and CBD, affect both mental and physical health issues over the next decade as more research is done.
If you want to try cannabis for mental health, Ammon suggests having a conversation with your healthcare provider first. “Talk to your medical provider about your interest and find out if they support the use of medical cannabis and can provide a script,” she says. “Also look at state regulations regarding obtaining a medical cannabis prescription. The types offered in these regulated stores are often cleaner and safer than drugs purchased from an unregulated provider.
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