By Elizabeth Short, Staff Writer, MedPage Today
National data show that cannabis use that does not reach the level of a diagnosable substance use disorder was associated with negative effects on mental health.
In the 2015-2019 National Surveys on Drug Use and Health, 2.5% of participants aged 12 to 17 reported repeated cannabis use in the past year to a degree that led to clinically significant impairment or distress and met the thresholds for a diagnosis of cannabis use disorder (CUD), according to Ryan S. Sultan, MD, of Columbia University in New York City, and co-authors.
But four times as many, 10.2%, reported non-disordered cannabis use (NDCU), meaning that their use in the previous month or year did not meet the Diagnostic and Statistical Manual of Mental Disorders (Five Edition) criteria for an official diagnosis, according to the published cross-sectional study.
In terms of impact, suicidal ideation was 2.08 times more likely among those with non-cannabis use (adjusted OR 2.08, 95% CI 1.88–2.29) compared to those who did not use cannabis at all in the previous year. Major depression was also significantly more common with non-cannabis use (aOR 1.86, 95% CI 1.67–2.08), as were difficulty concentrating (aOR 1.81, 95% CI 1.65–2.00) and slowed thinking (aOR 1.76, 95% CI 1.58–1.96).
NDCU was also associated with problems for these adolescents and pre-adolescents, including arrest (aOR 4.15, 95% CI 3.17-5.43), aggression (aOR 2.16, 95% CI 1.79-2.62), fighting (aOR 2.04, 95% CI 1.80-2.31), and truancy (aOR 1.90, CI
Sultan told MedPage Today via email that seeing such adverse effects in patients who are not experiencing a clear substance use disorder is surprising.
The primary purpose of labeling something as a mental health condition is to link it to an adverse impact on a person's life. These findings suggest that cannabis use, even at recreational levels, is associated with adverse outcomes in young people,” he said. “In the context of an epidemic of depression and suicide among young people, this is concerning.”
Based on previous studies, these findings support "underdiagnosed cannabis use" as a risk marker for adverse psychosocial events in adolescence, including major depression and suicidality, according to the researchers.
They noted a gradual severity gradient in the likelihood of psychosocial associations between non-use and non-consumer cannabis (NCC) levels. “This severity gradient was also observed in the prevalence of adverse psychosocial events across all levels of cannabis use. Furthermore, this observation was corroborated by a gradual trend in the frequency of cannabis use between NCC and NCC levels.”
For example, suicidal ideation was almost three times more likely among those with CUD (aOR 2.92, 95% CI 2.43–3.50) compared with those who did not use cannabis at all, while major depression was more than twice as likely (aOR 2.42, 95% CI 2.02–2.89). Other results followed a similar pattern.
The researchers noted that cannabis use itself could be a symptom of existing mental health problems, but it could also worsen pre-existing issues.
“Cannabis use in adolescence may represent self-treatment to improve mood symptoms and is also associated with the development of major depression,” they wrote. However, recent studies have suggested that continued use worsens mood symptoms. “Given the public perception of cannabis as a treatment for depressive symptoms, further longitudinal research is needed to better describe this association.”
As of last month, 21 U.S. states and the District of Columbia have legalized marijuana, and many of the remaining states have policies of decriminalization or exclusive use for medicines.
As laws and policies change against a backdrop of fairly positive public perceptions of cannabis use, but negative associations between mental health and cannabis, Sultan encouraged discussions about cannabis use among doctors and patients, noting that cannabis use could act as a "marker."
"Educators, parents, medical providers, and mental health professionals must be vigilant in detecting and treating cannabis use among young people," he said, noting that depression, suicide, truancy, and poor academic performance can have long-term negative effects on a young person's life trajectory.
A total of 68,263 participants responded to the survey, ranging in age from 12 to 17 years. The average age of those surveyed was 14.5 years, and males represented 50.9% of the study population.
The limitations of this study included self-reported data that did not account for potential psychiatric comorbidities prior to cannabis use. "If anxiety were a common cause of both cannabis use and psychosocial events, it could partially or even completely explain the observed associations between cannabis use and psychosocial events," the researchers noted.
Due to the cross-sectional and observational nature of this study, direct causality between cannabis use and psychological events could not be determined.