Cannabis has become more widely accepted in many parts of the world in recent years.
Some countries and regions have legalized its use for medical or recreational purposes, and many young people believe it is a relatively harmless drug.
Social media often portrays cannabis as a natural way to relax, improve sleep, or deal with stress.
However, scientists are increasingly concerned about how regular cannabis use may affect mental health, especially in teenagers and young adults.
A new international study led by researchers from the University of Queensland has found that young people who use cannabis every day are up to four times more likely to develop psychosis than people who do not use cannabis.
Psychosis is a serious mental health condition that affects the way a person thinks and experiences reality. People with psychosis may hear voices, see things that are not there, or develop false beliefs that seem completely real to them.
The study reviewed evidence from 17 previous studies that examined whether cannabis use contributes to mental health problems, including psychosis, bipolar disorder, depression, and anxiety. The researchers found that the link between daily cannabis use and psychosis was the strongest and most consistent result.
Associate Professor Janni Leung from the University of Queensland’s National Centre for Youth Substance Use Research explained that young people are particularly vulnerable because their brains are still developing.
During the teenage years and early adulthood, important parts of the brain continue to mature. This period is also when many mental health conditions first appear and when cannabis use often begins. According to the researchers, this combination creates a particularly high-risk situation.
The study also found another worrying pattern. Around one in three people between the ages of 15 and 25 who used cannabis every day or almost every day developed cannabis use disorder.
This condition means that people struggle to control their cannabis use even when it causes problems in their health, studies, work, or relationships. Some people may want to stop using cannabis but find that they cannot easily cut back or quit.
Researchers also found evidence that daily cannabis use may worsen symptoms of bipolar disorder. Bipolar disorder is a mental illness that causes extreme changes in mood, energy levels, and activity. These mood swings can interfere with work, relationships, and everyday life.
The evidence connecting cannabis with depression and anxiety was less certain. However, some studies reviewed by the researchers found that mental health symptoms improved when people reduced their cannabis use or stopped using it entirely.
The University of Queensland team also participated in another study published in The Lancet Psychiatry. This review found no clear evidence that medicinal cannabis effectively treated anxiety, depression, or sleep disorders. These findings challenge the growing belief that cannabis products can replace established treatments for mental health conditions.
The researchers are urging policymakers and healthcare professionals to be cautious. They recommend that doctors routinely ask patients about cannabis use and screen for mental health conditions at the same time.
People who have both cannabis use disorder and mental health problems often experience poorer outcomes and may need treatment that addresses both issues together.
This review does not prove that cannabis directly causes psychosis because it examined previous studies rather than conducting a new experiment. However, the consistency of the findings across many studies makes the association difficult to ignore.
The fact that daily users had up to four times the risk of psychosis suggests that heavy cannabis use may be an important factor in mental health problems among young people. The findings also raise questions about increasing cannabis use and changing public attitudes toward the drug.
Future studies will need to clarify why some young people are especially vulnerable and whether reducing cannabis use can lower the risk of developing serious mental illnesses.
If you care about cannabis, please read studies that what you need to know about cannabis and heart attack, and CBD from cannabis may help inhibit COVID-19 infection.
For more information about cannabis, please see recent studies that medical cannabis could help reduce depression, and results showing this stuff in cannabis may protect aging brain, treat Alzheimer’s.
