Initiating Cannabis Usage for Self-Medication Linked to Higher Rates of Depression, Paranoia: Study

Marijuana users are at a significantly higher risk of developing a psychotic disorder.

Picture of a cannabis plant taken at the Cannabis Expo Brazil, a hemp and cannabis industry exhibition, in Sao Paulo, Brazil, on Sept. 15, 2023. Nelson Almeida/AFP via Getty Images

People who first use cannabis for self-medication purposes have been associated with a higher average rate of consumption as well as increased anxiety, depression, and paranoia, according to a new study published in the journal BMJ Mental Health.

The study participants reported a mean weekly consumption of 206 Tetrahydrocannabinol (THC) units. The THC unit is a standardized measure of the primary psychoactive compound in cannabis.

“Initiating cannabis use for anxiety, depression or because ‘family members were using it’ was associated with higher weekly THC units,” the study said.

Using cannabis for the first time to relieve physical discomfort, pain, anxiety, depression, and minor psychotic symptoms were linked to higher paranoia scores.

However, starting cannabis usage for “fun” or “curiosity” was associated with lower paranoia and anxiety, while usage for “boredom” was linked to increased depression.

Based on data collected from the study, 69.8 percent reported starting to use cannabis because of friends, 62.3 percent out of curiosity, and 52.7 percent for fun.

About 15.4 percent reported starting use to relieve anxiety, 13.8 percent to relieve depression, 7.6 percent to relieve pain, and 6 percent to relieve physical discomfort.

The peer-reviewed study looked at how reasons for first using cannabis impacted later-use patterns and mental health outcomes for the individuals.

It analyzed data from 3,389 people with lifetime use of cannabis, collected between March 2022 and July 2024, and was done by researchers mostly from King’s College London. The results were published on Aug. 26.

Participants were all above the age of 18, residents of the London area or able to travel, English speakers, and did not have a past diagnosis of psychotic disorders. They had a mean age of 30.9 years, and a majority were white, British, and employed.

Data for the study were taken from the Cannabis&Me population survey. Cannabis&Me has been supported by various charitable trusts. The funders were not involved in the design and conduct of the study or the collection, management, analysis, or interpretation of the data. Two of the study authors reported fees from pharmaceutical companies such as Janssen, Lundbeck, Sunovion, and Otsuka. No other authors declared any conflict of interest.

Psychosis Links, Trump Administration’s Reclassification

The Epoch Times had earlier reported on the links between marijuana or cannabis use and mental issues, especially its impact on young people.

A May 2024 study in the journal Psychological Medicine found that teens who use marijuana are at a significantly higher risk of developing a psychotic disorder.

“We found a very strong association between self-reported cannabis use and risk of psychotic disorder in adolescence,” said lead author André McDonald. “These findings are consistent with neurodevelopmental theory that teens are especially vulnerable to the effects of cannabis.”

Compared to non-users, the researchers discovered an 11 times higher risk of developing psychotic disorders, including schizophrenia, for marijuana users.

Another study in the same journal published in August 2024 explored the impact of childhood trauma and cannabis use on paranoia.

The study findings said that childhood trauma was a primary driver of paranoia and that cannabis use amplified its effects.

“Cannabis played a significant mediating role” to increase paranoia, said the study.

Meanwhile, the Trump administration is looking to give marijuana a more moderate classification. The Biden administration had also looked to reclassify marijuana as a less harmful drug.

On Aug. 11, while answering reporters’ questions, President Donald Trump said: “Some people like it. Some people hate it—some people hate the whole concept of marijuana, because it does bad for the children [and] it does bad for people that are older than children.

“But we’re looking at reclassification, and we’ll make a determination over the next few weeks—and that determination, hopefully, will be the right one. Very complicated subject.

“I’ve heard great things having to do with medical [and] bad things having to do with just about everything else.”

Alcohol-Like Unit Measurements for Cannabis

A King’s College statement on the study said, “The use and potency of cannabis is increasing worldwide, and dependence and cannabis-induced psychosis are also greatly increasing as a result, especially in North America.”

Researchers found that the average respondent consumed 206 units of THC a week, which is roughly 10–17 “joints,” with an expected 20 percent THC content.

“However, respondents who started using cannabis to help with their anxiety, depression, or in cases where they started due to others in their household who were already using cannabis, reported on average 248, 254.7, and 286.9 average weekly THC units, respectively,” the statement said.

Professor Tom Freeman, director of the Addiction and Mental Health Group at the University of Bath, said, “In future, standard THC units could be used in a similar way to alcohol units—for example, to help people to track their cannabis consumption and better manage its effects on their health.”

“My experience in clinic tells me that there are groups of people who start to use cannabis as a means of coping with physical and emotional pain,” said Marta Di Forti, professor of drug use, genetics, and psychosis at King’s IoPPN, and clinical lead at the South London and Maudsley NHS Foundation Trust’s Cannabis Clinic for Patients With Psychosis.

“My research has confirmed that this is not without significant further risk to their health and wellbeing, and policy makers across the world should be mindful of the impact that legalisation, without adequate public education and health support, could have on both the individual, as well as on health care systems more broadly.”