Adverse Effects of Cannabis Use in Individuals Under 18


Cannabis use among adolescents is a growing concern due to its potential impact on brain development and overall health. Adolescents are particularly vulnerable to the adverse effects of cannabis because their brains are still developing, which can lead to long-term negative consequences.

Cognitive Impairments

  1. Memory and Learning:
  • Cannabis use can impair short-term memory and learning abilities. THC (tetrahydrocannabinol), the psychoactive component of cannabis, disrupts the functioning of the hippocampus, a brain area crucial for memory formation .
  • Adolescents who use cannabis may have difficulties retaining information, affecting their academic performance and cognitive development.
  1. Attention and Concentration:
  • Regular cannabis use can lead to problems with attention and concentration. This impairment can interfere with schoolwork and other activities that require sustained mental effort .
  1. IQ Decline:
  • Long-term studies suggest that heavy cannabis use during adolescence can result in a significant decline in IQ. This decline persists even after cessation of use, indicating potential long-lasting effects on cognitive abilities .

Mental Health Issues

  1. Anxiety and Depression:
  • Cannabis use can exacerbate symptoms of anxiety and depression in adolescents. Some studies indicate that individuals who start using cannabis at a young age are more likely to develop mental health disorders later in life .
  • The risk is particularly high for those with a family history of mental health issues or pre-existing conditions.
  1. Psychosis and Schizophrenia:
  • There is a strong association between cannabis use and the onset of psychosis, especially in individuals with a genetic predisposition. Adolescents who use high-potency cannabis are at a higher risk of developing psychotic symptoms .
  • Early and frequent use can increase the likelihood of developing schizophrenia or other severe mental health disorders .

Impact on Brain Development

  1. Structural Changes:
  • Cannabis use during adolescence can cause structural changes in the brain, particularly in areas involved in decision-making, emotional regulation, and impulse control .
  • These changes can affect behavior and cognitive functions, potentially leading to issues with self-regulation and increased risk-taking behavior.
  1. Neurodevelopmental Effects:
  • The adolescent brain undergoes significant development, including the maturation of the prefrontal cortex, which is critical for executive functions. Cannabis use can interfere with this process, leading to deficits in planning, decision-making, and social behavior .

Physical Health Consequences

  1. Respiratory Problems:
  • Smoking cannabis can cause respiratory issues similar to those caused by tobacco smoke, including chronic bronchitis and other lung conditions. Adolescents who smoke cannabis are at risk of developing long-term respiratory problems .
  • Vaping and edibles might reduce some respiratory risks, but these methods also have their own set of potential health concerns.
  1. Impact on Growth and Development:
  • Cannabis use can negatively affect physical development. Some studies suggest that regular cannabis use during adolescence can impact hormonal regulation, potentially affecting growth and pubertal development .

Social and Behavioral Issues

  1. Academic and Occupational Outcomes:
  • Adolescents who use cannabis frequently are more likely to experience poor academic performance, higher dropout rates, and reduced educational attainment .
  • These academic challenges can translate into difficulties in finding and maintaining employment in adulthood.
  1. Substance Use Disorder:
  • Early cannabis use increases the likelihood of developing a substance use disorder. Adolescents who use cannabis are more prone to experimenting with other illicit drugs and developing addiction problems .


Cannabis use during adolescence can have profound and lasting adverse effects on cognitive, mental, and physical health. It is crucial for parents, educators, and healthcare providers to educate young people about these risks and promote healthy, substance-free lifestyles. Early intervention and support can help mitigate the negative impacts and guide adolescents towards safer developmental trajectories.


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