Youth Cannabis Use and Mental Health in Adulthood: What Families Need to Know
Cannabis use among teenagers can be difficult for families to discuss.
Some conversations frame cannabis as relatively harmless because it is legal for adults in Canada and has become widely accepted. Others rely on frightening warnings that can leave young people feeling judged, defensive, or unwilling to speak honestly.
Neither approach provides the full picture.
Cannabis use during adolescence does not guarantee that a young person will develop a mental health disorder. However, a growing body of research shows that youth who use cannabis face significantly higher risks of serious mental health concerns during adolescence and early adulthood.
These concerns include depressive disorders, anxiety disorders, psychotic disorders, bipolar disorder, cannabis use disorder, and difficulties involving cognition and emotional regulation. Risk may be greater when cannabis use begins earlier, becomes frequent, or involves higher-potency products.
This information should not be used to shame young people or suggest that their future has already been determined. It should help families understand why youth cannabis use deserves informed attention, appropriate boundaries, and early support.
Adolescence Is Not the Same as Adulthood
Adolescence is an important period of neurological, emotional, cognitive, and social development.
Young people are still developing their ability to manage difficult emotions, control impulses, consider consequences, make decisions, sustain attention, navigate conflict, and respond flexibly when life becomes uncomfortable.
These abilities develop gradually through experience. Young people build emotional regulation by learning how to move through anxiety, disappointment, frustration, loneliness, boredom, social pressure, and uncertainty without becoming completely overwhelmed or dependent on one form of relief.
Cannabis may temporarily reduce or change uncomfortable feelings. A young person may experience it as a way to relax, sleep, quiet racing thoughts, reduce social discomfort, or create distance from emotional pain.
That short-term relief can be real. It does not necessarily mean cannabis is improving the underlying concern or supporting healthy emotional development over time.
When cannabis becomes a young person’s primary or automatic response to distress, it may reduce opportunities to practise other forms of emotional regulation, problem-solving, and distress tolerance. It may also make it more difficult to identify and address the anxiety, sadness, trauma, conflict, isolation, or pressure contributing to the use.
The research does not show that cannabis permanently removes a young person’s emotional capacity. A more accurate concern is that early and repeated cannabis use may interfere with the development and consistent use of emotional regulation and executive-function skills that are still taking shape during adolescence.
A Major Study Followed More Than 463,000 Adolescents
A large cohort study published in JAMA Health Forum in February 2026 examined the relationship between adolescent cannabis use and later clinician-diagnosed psychiatric disorders.
Researchers studied 463,396 adolescents between the ages of 13 and 17 who received healthcare through Kaiser Permanente Northern California. The adolescents were confidentially screened for past-year cannabis use during routine healthcare visits and followed through age 25.
The researchers examined whether cannabis use was associated with later psychotic, bipolar, depressive, or anxiety disorders.
Compared with adolescents who did not report past-year cannabis use, those who did had:
More than twice the risk of developing a psychotic disorder
Approximately twice the risk of developing bipolar disorder
A 34 per cent higher risk of developing a depressive disorder
A 24 per cent higher risk of developing an anxiety disorder
The associations remained statistically significant after the researchers adjusted for several factors, including alcohol and other substance use, demographic characteristics, neighbourhood deprivation, insurance type, and previous psychiatric conditions.
The researchers also conducted an analysis that excluded adolescents who already had a history of psychotic, bipolar, depressive, anxiety, or disruptive behaviour disorders. The associations remained significant.
The strongest results involved psychotic and bipolar disorders. However, the increased risks of depressive and anxiety disorders were also significant and were more pronounced among younger adolescents.
These findings suggest that adolescence may be a particularly vulnerable period and that delaying cannabis use matters.
Association Is Not the Same as Certainty
The JAMA Health Forum study was observational. It identified strong associations but could not prove that cannabis alone caused every later psychiatric diagnosis.
Mental health disorders develop through a combination of biological, psychological, social, developmental, behavioural, genetic, and environmental factors.
Some young people may begin using cannabis because they are already experiencing anxiety, low mood, sleep difficulties, trauma-related symptoms, emotional distress, social isolation, or early psychiatric symptoms that have not yet been recognized.
Cannabis use may contribute to later concerns. Existing mental health concerns may contribute to cannabis use. Shared vulnerabilities may increase the likelihood of both.
The researchers could not fully account for every possible influence, including adverse childhood experiences, genetic vulnerability, parental mental health, frequency of cannabis use, method of use, or THC concentration.
These limitations do not make the findings unimportant. They mean the research should be understood as evidence of increased risk rather than a prediction of what will happen to every young person.
Cannabis Use and Later Depression
The relationship between cannabis use and later depression has been found across multiple longitudinal studies.
A 2025 systematic review and meta-analysis examined 22 longitudinal studies that measured cannabis use before later depression. Most participants were under 18 when cannabis exposure was first assessed.
The analysis found that people who used cannabis had 29 per cent higher odds of later depression than those who did not.
The authors noted that the studies varied in how they defined cannabis exposure, frequent use, and depression. Even with those differences, the overall evidence supported an association between cannabis use and increased depression risk.
A separate systematic review and meta-analysis published in JAMA Psychiatry examined 11 studies involving 23,317 participants. It found that cannabis use during adolescence was associated with an increased risk of major depression in young adulthood.
The relationship can be complicated and may move in more than one direction.
A young person who feels depressed, emotionally numb, overwhelmed, or disconnected may use cannabis to create temporary relief. Continued use may then contribute to reduced activity, withdrawal from relationships, disrupted sleep, lower motivation, difficulty meeting responsibilities, or greater reliance on cannabis to feel okay.
The important question is not simply whether cannabis or depression came first. When the two appear together, both deserve attention.
Cannabis Use and Later Anxiety
Young people may also use cannabis because they believe it helps them manage anxiety.
They may experience temporary relief from racing thoughts, social discomfort, school pressure, sleep difficulties, or emotional tension. That experience should not be dismissed.
At the same time, temporary relief does not necessarily translate into improved anxiety over time.
A 2024 systematic review and meta-analysis examined prospective research on adolescent cannabis use and later anxiety. The quantitative analysis found that adolescents who used cannabis had more than twice the odds of developing a later anxiety disorder compared with adolescents who did not use it.
The broader systematic review included 12 longitudinal studies. Nine found a significant prospective relationship between adolescent cannabis use and later anxiety symptoms or disorders.
The authors remained appropriately cautious about causation. Anxiety may contribute to cannabis use, cannabis may contribute to anxiety, or other factors may contribute to both.
The findings do show that cannabis should not be assumed to be a reliably protective or effective response to adolescent anxiety.
When a young person increasingly depends on cannabis to attend school, socialize, sleep, manage conflict, or tolerate difficult thoughts and feelings, the underlying anxiety still needs to be understood and addressed.
Serious Psychiatric Disorders Cannot Be Ignored
Although anxiety and depression may be more familiar to families, the stronger psychiatric findings in the 2026 study should not be minimized.
Adolescents who reported past-year cannabis use had more than twice the risk of later psychotic disorders and approximately twice the risk of bipolar disorder.
Most young people who use cannabis will not develop either condition. Psychotic and bipolar disorders involve complex genetic, developmental, neurological, environmental, and clinical factors.
Cannabis may nevertheless increase or accelerate risk for some young people, particularly those with an existing vulnerability.
The possibility becomes more concerning when use begins early, occurs frequently, or involves products containing higher concentrations of THC.
Families may not know the potency of the cannabis a young person is using. Products may include concentrated cannabis extracts, vaping products, edibles, or cannabis flower with THC levels that are considerably higher than products available in previous decades.
A 2024 study of adolescents found that use of higher-potency cannabis was associated with a greater likelihood of depression, anxiety, and auditory experiences after accounting for several potential confounding factors.
While potency is not the only factor, this does support the concern that not all cannabis products carry the same level of risk.
Cognitive and Emotional Functioning
Research has also examined the relationship between youth cannabis use and cognition.
A 2024 scoping review of youth cannabis research reported associations involving reduced cognitive functioning, memory, attention, learning, executive functioning, mental health concerns, and cannabis dependence. More frequent or prolonged use was generally connected with greater concern.
Executive functions help people plan, organize, remember information, control impulses, solve problems, adjust their behaviour, and make decisions based on longer-term goals rather than immediate relief.
Difficulties in these areas can affect school attendance, academic performance, employment, relationships, routines, decision-making, and the ability to follow through on responsibilities.
A longitudinal neuroimaging study published in JAMA Psychiatry examined brain imaging from 799 adolescents at approximately age 14 and again five years later. Cannabis use during adolescence was associated with differences in cortical development, particularly in areas of the brain undergoing substantial age-related change.
The researchers described an association with altered neurodevelopment. The study did not prove that cannabis caused permanent brain damage or that every adolescent who uses cannabis will experience the same changes.
Some cognitive difficulties may improve after cannabis use is reduced or stopped. Findings vary across studies, and outcomes may be influenced by age of first use, frequency, potency, duration of use, other substance use, existing vulnerabilities, and length of time since last use.
The responsible message is not that cannabis inevitably destroys a developing brain. It is that repeated exposure during a significant developmental period may affect abilities and emotional processes that young people are still establishing.
Cannabis May Be Meeting a Real Need
A young person’s cannabis use may create risk while still serving an understandable purpose.
They may be trying to manage:
Anxiety or racing thoughts
Difficulty sleeping
Sadness or emotional numbness
Social discomfort
Family conflict
Academic or employment pressure
Loneliness or isolation
Trauma or grief
Boredom or lack of connection
Pressure to fit in with peers
Understanding the purpose of the behaviour means recognizing that removing cannabis without addressing the reason it became important may leave the original concern unresolved.
When the underlying need remains, the young person may return to cannabis, become increasingly secretive, or shift their reliance to another behaviour.
A more effective response combines clear expectations and accountability with genuine attention to the young person’s mental health, relationships, environment, and reasons for using.
What Families May Notice
Cannabis use does not always produce obvious signs, and no single change proves that a young person is using cannabis or developing a mental health disorder.
Patterns that deserve closer attention may include:
Increasingly frequent or daily cannabis use
Using before school, work, sports, or other responsibilities
Believing cannabis is needed to sleep, eat, socialize, or feel normal
Increasing isolation from family or established friendships
Loss of interest in activities that previously mattered
Significant changes in school attendance, performance, or motivation
New difficulties with concentration, memory, or organization
Persistent anxiety, low mood, irritability, or emotional withdrawal
Spending increasing amounts of money on cannabis
Unsuccessful attempts to reduce or stop
Continuing to use despite problems at home, school, work, or in relationships
Unusual changes in thinking, perception, suspicion, fear, or behaviour
It is important not to interpret every difficult week or ordinary adolescent mood as evidence of cannabis-related harm.
The concern is a pattern that persists, escalates, or begins interfering with the young person’s daily functioning, relationships, responsibilities, or well-being.
Starting the Conversation Without Shame
Families do not need a carefully prepared script to begin addressing cannabis use.
The conversation is more likely to be useful when it is based on specific observations, genuine concern, and a willingness to listen. Beginning with accusations, labels, threats, or exaggerated claims can quickly turn the discussion into an argument about whether cannabis is harmful rather than an honest examination of what is happening.
Young people may minimize their use, become defensive, or insist that cannabis helps them. Families can listen without agreeing and remain clear that the concern is real.
Listening does not require removing boundaries or accepting unsafe behaviour. It helps families understand the pattern well enough to respond appropriately.
The first conversation may not lead to immediate disclosure or change. Maintaining a calm and consistent approach can make it more likely that the young person will speak honestly when they are ready.
Support Should Address More Than Cannabis
When cannabis use overlaps with anxiety, depression, trauma, cognitive difficulties, behavioural changes, or other psychiatric symptoms, focusing only on stopping the cannabis may not be enough.
A young person may need support to:
Understand their cannabis use and its effects
Identify emotional and situational triggers
Develop additional ways of managing distress
Rebuild sleep, school, and daily routines
Strengthen emotional regulation and coping skills
Address anxiety, depression, trauma, or family conflict
Reconnect with meaningful activities and relationships
Receive an appropriate medical or mental health assessment
Families may also need guidance and support.
Concern about a young person can lead family members to become consumed by monitoring, searching, arguing, rescuing, or trying to control every decision. This can affect the entire household without resolving the underlying problem.
Healthy boundaries focus on safety, responsibilities, access to family resources, and what family members will do in response to specific circumstances. They do not depend on shame, humiliation, or attempting to control everything the young person thinks or feels.
Early Attention Is Not an Overreaction
Families sometimes wait because they are afraid of damaging the relationship, overreacting, or placing a label on the young person.
Early attention does not require assuming that a young person has developed an addiction or serious psychiatric disorder.
It may begin with a conversation, an appointment with a family doctor or nurse practitioner, a mental health assessment, or a consultation with a qualified substance use professional.
The purpose is to understand what is happening before patterns become more established and consequences become more difficult to address.
The earlier cannabis becomes part of a young person’s coping system, the more important it is to help them build alternatives.
Risk Is Not Destiny
The research does not support treating adolescent cannabis use as harmless.
Youth who use cannabis have significantly higher risks of several mental health concerns during adolescence and early adulthood. These include depression, anxiety, psychotic disorders, bipolar disorder, cannabis use disorder, and cognitive difficulties.
The risk is not identical for every person. The presence of risk also does not mean that the outcome is inevitable.
Young people can change their relationship with cannabis. They can develop stronger emotional regulation and coping skills, receive appropriate mental health support, rebuild routines and relationships, and move toward a healthier adulthood.
Accurate information gives families a reason to pay attention. Compassionate accountability gives young people a better chance of accepting support.
Finding Support in London, Ontario
Families concerned about a young person’s cannabis use or mental health can begin by speaking with a family doctor, nurse practitioner, pediatrician, school-based professional, or qualified mental health or substance use practitioner.
ConnexOntario.ca provides free and confidential information about mental health and substance use services throughout Ontario.
EPIC Recovery primarily supports adults with mild to moderate substance use concerns, as well as family members and others affected by a loved one’s substance use. Families may contact EPIC for counselling and support related to communication, boundaries, substance use, and their own well-being.
Sudden or severe changes in thinking, perception, behaviour, or personal safety require prompt professional assessment.
Research Referenced
Young-Wolff, K. C., Cortez, C. A., Alexeeff, S. E., et al. (2026). Adolescent cannabis use and risk of psychotic, bipolar, depressive, and anxiety disorders. JAMA Health Forum, 7(2), e256839. https://doi.org/10.1001/jamahealthforum.2025.6839
Sanz-Pérez, A., Serrano, D. R., Fraguas-Sánchez, A. I., Pardo, M. C., Ruiz Sánchez de León, J. M., Estupiñá, F. J., Pérez, T., & González-Burgos, E. (2026). Growing concerns: A systematic review and meta-analysis of cannabis use and mental health risks in youth. Addictive Behaviors, 172, 108528. https://doi.org/10.1016/j.addbeh.2025.108528
Churchill, V., Chubb, C. S., Popova, L., Spears, C. A., & Pigott, T. (2025). The association between cannabis and depression: An updated systematic review and meta-analysis. Psychological Medicine, 55, e44. https://doi.org/10.1017/S0033291724003143
Lowe, D. J. E., Sorkhou, M., & George, T. P. (2024). Cannabis use in adolescents and anxiety symptoms and disorders: A systematic review and meta-analysis. The American Journal of Drug and Alcohol Abuse, 50(2), 150–161. https://doi.org/10.1080/00952990.2023.2299922
Gobbi, G., Atkin, T., Zytynski, T., Wang, S., Askari, S., Boruff, J., Ware, M., Marmorstein, N., Cipriani, A., Dendukuri, N., & Mayo, N. (2019). Association of cannabis use in adolescence and risk of depression, anxiety, and suicidality in young adulthood: A systematic review and meta-analysis. JAMA Psychiatry, 76(4), 426–434. https://doi.org/10.1001/jamapsychiatry.2018.4500
Baral, A., Hanna, F., Chimoriya, R., & Rana, K. (2024). Cannabis use and its impact on mental health in youth in Australia and the United States: A scoping review. Epidemiologia, 5(1), 106–121. https://doi.org/10.3390/epidemiologia5010007
Hines, L. A., Cannings-John, R., Hawkins, J., Bonell, C., Hickman, M., Zammit, S., Adara, L., Townson, J., & White, J. (2024). Association between cannabis potency and mental health in adolescence. Drug and Alcohol Dependence, 261, 111359. https://doi.org/10.1016/j.drugalcdep.2024.111359
Albaugh, M. D., Ottino-Gonzalez, J., Sidwell, A., et al. (2021). Association of cannabis use during adolescence with neurodevelopment. JAMA Psychiatry, 78(9), 1031–1040. https://doi.org/10.1001/jamapsychiatry.2021.1258