Cannabis can raise – or lower – depression risk among adolescents

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Research at Johns Hopkins University in America found a complicated and counterintuitive relationship between cannabis use among adolescents and depression, writes Eric W Dolan for PsyPost. Adolescents who had used cannabis at any point were more likely to show symptoms of depression – but more frequent consumption the reduced odds of depression.

“Depression and cannabis use often co-occur, but the reasons for this are still not fully understood. In this study, we attempted to determine whether frequency of cannabis use was associated with depressive symptoms,” said study author Natalie Gukasyan, a postdoctoral fellow at Johns Hopkins University School of Medicine.

“We chose to look at an adolescent population because this is a sensitive developmental period and is often the age of onset for both mood disorders and cannabis use. Given that prior studies have suggested that cannabis use may increase the risk of depression, we expected to find the highest rates of depression in those that used cannabis most frequently.”

The PsyPost article, published on 8 August 2020, reported on research published in March in the journal Drug and Alcohol Dependence. The study, “Relationship between cannabis use frequency and major depressive disorder in adolescents: Findings from the National Survey on Drug Use and Health 2012-2017”, was authored Natalie Gukasyan and Eric C Strain.

The research

The researchers examined data from 90,314 American adolescents who participated in the National Survey on Drug Use and Health. They found that depression was more prevalent among adolescents with any history of cannabis use compared to those with no history of cannabis use.

But among cannabis users, those who used the drug more frequently tended to have lower rates of depression than those who used it less frequently. Among users, 33.1% reported using cannabis one to 12 days in the past year, 14.6% reported using cannabis 13 to 51 days in the past year, and 32.7 % reported using cannabis more than 52 days in the past year.

“Any history of cannabis use in an adolescent, even if it was over a year ago, is associated with a higher risk of past year and lifetime major depressive episode. However, when we analysed adolescents with any history of cannabis use, the higher frequency users had lower risk of depression compared to lower frequency users when other factors were accounted for,” Gukasyan told PsyPost.

“Among the subset of adolescents with any history of cannabis use, the highest rate of past year major depressive episode was found in those that had last used cannabis over a year ago.”

After controlling for other factors, the researchers found that heavy cannabis use was not associated with significantly different odds of past year depression compared to never users.

Difficult to draw conclusions

“It is difficult to draw conclusions about why we observed this pattern,” Gukasyan said. The researchers believe the findings could reflect differences in motives for using cannabis, “with some adolescents using for subjective relief of depression, and others using for social or other factors”.

Differences in access to treatments for depression could also play a role, as could some methodological limitations.

“This was based on self-reported data, which is subject to recall and other types of bias. Cannabis use frequency may not be perfectly correlated to amount or dose of cannabis used – eg a daily smoker might use the same absolute amount of cannabis as someone who smokes a large quantity once per week, yet these individuals could have been analysed in separate groups,” Gukasyan explained.

“This analysis cannot conclude anything about the future risk of depression in cannabis users. Other studies, including prospective studies, have found that cannabis use during adolescence predicted higher likelihood of developing major depressive disorder and other mental health issues in adulthood.”

 

Relationship between cannabis use frequency and major depressive disorder in adolescents: Findings from the National Survey on Drug Use and Health 2012–2017

Drug and Alcohol Dependence, Volume 208. Published on 1 March 2020

Authors

Natalie Gukasyan and Eric C Strain

Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine.

Abstract

Highlights

Depression is more prevalent among adolescents with cannabis use compared to never users.

Among cannabis users, higher frequency of use was associated with lower rates of depression.

Consistent with prior research, female sex, past year alcohol use, and illicit drug use other than cannabis were associated with depression.

Background

Cannabis use and major depressive disorder (MDD) are common and often co-morbid in adolescents, but the nature and directionality of the relationship between these two conditions remains obscure.

Methods

We examined results from the National Survey on Drug Use and Health. Weighted demographics were compared between adolescents with a history of cannabis use (N = 14,873) and never users (N = 73,079). Weighted logistic regression controlling for demographic variables and other substance use was used to determine the relationship between cannabis use frequency and MDD.

Results

Adolescents with any history of cannabis use had significantly higher rates of lifetime and past year MDD, MDD with severe role impairment, and past year suicide attempt (p < 0.001).

Comparing use frequency groups in the adjusted model revealed that heavy users (weekly or greater use) had significantly lower predicted prevalence of lifetime and past year MDD, and past year MDD with severe role impairment compared to light users and those who used cannabis >1 year ago.

Rates of reported past year suicide attempt did not differ significantly by cannabis use frequency.

Conclusions

Adolescents with any cannabis use history have significantly higher rates of MDD. However, the directionality between frequency of use and MDD is counter to what was expected.

 

New research raises questions about the link between cannabis use and depression among adolescents

 

Relationship between cannabis use frequency and major depressive disorder in adolescents: Findings from the National Survey on Drug Use and Health 2012–2017

 


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