Marijuana Use in Teens: Risks and Recommendations
Direct Answer
Teenagers should not use marijuana under any circumstances due to severe, potentially permanent neurodevelopmental damage that occurs uniquely during adolescence, with effects including cognitive impairment, increased risk of psychosis and schizophrenia, and structural brain changes that develop more rapidly than in adults. 1, 2
Critical Neurodevelopmental Risks
Brain Structural Damage
The adolescent brain is uniquely vulnerable to cannabis-induced damage through specific mechanisms:
- Glutamate excitotoxicity: Cannabis inhibits GABAergic inhibitory action on glutaminergic neurons, causing increased susceptibility to excitotoxic damage in the developing brain 1, 2
- Structural alterations: Cannabis causes altered grey matter volume, reduced cortical thickness, and disrupted prefrontal cortex connectivity—changes that occur more rapidly in adolescents than adults 1, 2
- Orbitofrontal cortex damage: This region essential for adolescent decision-making shows specific vulnerability to cannabis effects 1
- Altered dopamine and glutamate signaling: These neurochemical changes contribute directly to cognitive deficits and heightened psychosis risk 1, 2
Cognitive and Functional Impairments
Cannabis use during adolescence causes measurable deficits across multiple domains:
- Memory and learning: Deficits in episodic memory, verbal learning, and information processing speed 1, 2
- Executive function: Impaired decision-making, inhibitory processing, and attention control 1, 2
- Academic performance: Direct negative impacts on school performance and cognitive development 3, 4
Psychiatric Consequences
Psychotic Disorders
The risk of schizophrenia and psychosis represents one of the most severe consequences:
- Heightened risk for transition to schizophrenia and psychosis, attributed to cannabis-related alterations in glutamate and dopamine signaling 1, 2
- High doses of THC are associated with acute psychotic symptoms in vulnerable individuals 2, 5
- Cannabis worsens positive psychotic symptoms and total psychiatric symptoms in those with existing vulnerability 2, 5
Mood and Anxiety Disorders
- Increased risk for developing depressive disorders and suicidal ideation or behavior 2, 3
- Enhanced risk for ADHD and anxiety disorders 1
- Older adults who use cannabis show higher risk for behavioral health issues including anxiety and depression, suggesting long-term psychiatric vulnerability 2
Addiction Risk
Early initiation dramatically increases addiction vulnerability:
- Early onset of cannabis use, especially weekly or daily use, strongly predicts future dependence 2
- Approximately 10% of adults with chronic cannabis use develop cannabis use disorder characterized by clinically significant impairment 2
- A randomized trial found participants receiving a medical cannabis card had almost twice the incidence of developing cannabis use disorder within 12 weeks 2
Physical Health Risks
Cardiovascular Effects
- Adverse cardiovascular events including arrhythmias, tachycardia, and orthostatic hypotension with acute use 2
- Long-term use associated with myocardial infarction and stroke 2
- Cannabis causes coronary vasoconstriction, increases endothelin-1, decreases nitric oxide, and promotes a prothrombotic state through increased platelet activation 2
Respiratory Complications
- Cannabis smoking affects lung function and is associated with chronic bronchitis and chronic obstructive pulmonary disease 2
- Cannabis smoke contains hundreds of compounds that act as respiratory irritants 6
- Vaping cannabis poses unique risks, as demonstrated by the 2019 outbreak of acute lung injury associated with THC concentrate and vitamin E acetate 2
Cannabinoid Hyperemesis Syndrome
- Long-standing cannabis use can lead to cannabinoid hyperemesis syndrome, characterized by cyclical emetic episodes relieved by hot showers 2
- Treatment focuses on cannabis cessation 2
Critical Potency Considerations
The danger has escalated dramatically with modern cannabis products:
- Average THC concentration almost doubled from 9% in 2008 to 17% in 2017, significantly elevating all health risks 2, 5
- Cannabis concentrates may have THC levels as high as 70%, which intensifies adverse health effects 2
- Higher doses of THC are associated with more severe acute effects, including psychosis in vulnerable individuals 2
- Vaping delivers higher concentrations of psychoactive properties compared to smoking 6
Age-Specific Vulnerability
Adolescence represents a uniquely dangerous period for cannabis exposure:
- Neural changes occur more rapidly among adolescents than adults, and many cannabis-related structural changes are unique to this age group 1
- The developing adolescent brain shows increased susceptibility to cannabis-induced excitotoxicity and structural damage 2
- Early initiation of cannabis use causes the most severe and lasting neurological damage 2
- Cannabis use may have a deleterious effect on adolescent brain development that persists into adulthood 2
Clinical Recommendations for Healthcare Providers
Screening Approach
- All teenagers should be screened for cannabis use using validated screening tools 1
- Screen for underlying mental health disorders that may co-occur with cannabis use 6
- Address risky behaviors in a sensitive and confidential manner, recognizing that adolescents may use substances to feel normal and part of their peer group 1
Education and Counseling
- Provide age-specific education about cannabis risks starting in elementary education and continuing through high school 6
- Educate on the documented health effects including respiratory, cardiovascular, and neurological impacts 2
- Emphasize that cannabis should not be used if there is a history of psychotic episodes or breaks with reality 5
- Counsel on methods for lowering risk if an adolescent chooses to continue use, including avoiding high THC-content products, synthetic cannabinoids, and inhalation of combusted cannabis 1
Treatment Focus
- The primary treatment goal is cannabis cessation 2, 5
- Behavioral therapies are currently the mainstay of treating cannabis misuse, with no pharmacotherapies currently approved by the FDA for cannabis use disorder in youth 4
- Long-term daily cannabis users may experience non-life-threatening withdrawal symptoms after cessation, including sleep disturbances, appetite changes, and abdominal pain, typically occurring within 3 days and lasting up to 14 days 2
Protective Factors
- Provide positive reinforcement for not using cannabis 1
- Improve quality of life, self-efficacy, and spirituality 6
- Provide teenagers with opportunities to naturally stimulate the brain's reward center 6
Critical Pitfalls to Avoid
Do not minimize the risks based on legalization trends: Despite marijuana legalization in various states, these changes coincide with a decrease in perceived harmfulness and an increase in use among youth—a trend of critical concern given the potential harmful impact on adolescents 3
Do not assume cannabis is safe for medical use in adolescents: There are very limited FDA-approved cannabinoid medications, none supporting their use for the treatment of psychiatric symptoms in youth 4
Do not overlook medication interactions: Cannabis can potentiate unwanted side effects of anxiety medications and fundamentally undermine antipsychotic treatment goals 5
Do not ignore the permanency of damage: Current evidence indicates that adolescence is a sensitive period during which cannabis use results in adverse neurocognitive effects that show a level of permanency into adulthood 7