Laws on cannabis (and its most popular product, marijuana) are paving the way for increased use of this substance in Latin America, the Caribbean, and the United States, both for medical and recreational purposes.

These legislative changes have been considered a victory for individual freedoms and a step forward for patients who have used marijuana for pain relief from, for example, cancer treatments. However, they have also opened the door to increased cannabis use in a socially and medically vulnerable population: adolescents.

The brains of teenagers, who are beginning to define themselves as individuals in society at this stage of life, are still in development, and cannabis can have a major negative impact. This was underscored in a recent study, the latest of hundreds that have investigated this issue, especially in association with mental health conditions.

This study primarily analyzed the relationship between psychosis symptoms and marijuana use. With a cohort of 11,868 adolescents, it found that those who used cannabis at any point during the study period reported a greater number of psychosis spectrum symptoms and more distress from those symptoms relative to those who never used cannabis.

Experts explain that adolescent cannabis use has been frequently posited to contribute to the onset and progression of psychosis—and worsening of an existing diagnosis. Part of the problem, they say, is that marijuana is considered a “soft” drug (in the public mind, less dangerous) and teenagers are using it to “self‑medicate,” believing that it may relieve the symptoms they do not understand that they are experiencing.

Psychosis (and one of its most well‑known manifestations, schizophrenia) is a mental disorder that causes strange thoughts, perceptions (visual or auditory), behaviors, and emotions. It can improve or worsen with environmental factors, such as drug use and stress.

This study’s findings underscore the importance of taking into account shared vulnerability and the effects of self‑medication when modeling associations between cannabis and psychosis risk, especially in adolescence. These studies also explored interventions to help prevent consumption of this drug, as adolescent cannabis use has also been found to be associated with an increased risk of psychosis later in life.

Another recent meta‑analysis evaluated 63 studies that investigated the impact of the use of this hallucinogenic herb and its association with academic performance. It concluded that cannabis use during adolescence and early adulthood is probably associated with increased absenteeism and dropout rates; reduced likelihood of achieving good grades, graduating high school, enrolling in university, and getting a postsecondary degree; and perhaps increased unemployment in the future. The authors highlighted the need for more research to identify interventions and policies that mitigate the factors associated with early cannabis exposure.

Going beyond the association between marijuana and mental health disorders, researchers used 11 studies, with a total of 23,317 participants, to look into the underlying relationships between cannabis use and other disorders. They concluded that the “high prevalence of adolescents consuming cannabis generates a large number of young people who could develop depression and suicidality attributable to cannabis.” They added that it is an important public health problem and concern that should be properly addressed by healthcare policies.

The mechanisms by which cannabinoids (the hundreds of components of cannabis) produce transient psychotic symptoms are unclear but may involve neurotransmission of dopamine, GABA, and glutamate. The dose, duration of exposure, and age at first exposure to cannabinoids may be important factors as well.

The combination of this first “curious” contact with the teen's personality, heredity, and health determinants can turn this transient psychedelia into a psychosis diagnosis.

Experts agree that the strategy to address adolescent cannabis use must be multifactorial. Family is the natural first step in creating a preventive barrier by allowing the teen to overcome use through confrontation with facts that demonstrate risk and honest communication.

At a social and legislative level, the American Academy of Child & Adolescent Psychiatry (AACAP) has been blunt: “Marijuana‑related policy changes, including legalization, may have significant unintended consequences for children and adolescents. AACAP supports (a) initiatives to increase awareness of marijuana’s harmful effects on adolescents, (b) improved access to evidence‑based treatment for adolescents with marijuana‑related problems, and (c) careful monitoring of the effects of marijuana‑related policy changes on child and adolescent mental health.”

This organization and the others that have echoed it strongly advocate for the involvement of the medical and research community in these critical and highly impactful policy‑related discussions.