Marijuana Use in Adults Over 50 Was Linked to Higher Rates of Depression and Suicidal Thoughts | Research

The takeaway

In a national survey of nearly 30,000 adults aged 50+, marijuana-only users had 1.5x higher odds of major depression compared to non-users, though among all illicit drug users, marijuana users were not worse off than other drug users.

Older adults who use cannabis and clinicians working with aging populations.

Marijuana-only users over 50 had 1.54x odds of major depression vs. non-users

What the researchers found

Researchers analyzed data from nearly 30,000 Americans aged 50 and older to examine the relationship between marijuana use and depression and suicidal thoughts in this understudied population.

About 6% of adults over 50 reported past-year illicit drug use. Compared to non-users, marijuana-only users had 1.54 times higher odds of a major depressive episode. Those using both marijuana and other drugs had 2.12 times higher odds, while those using other drugs only had 2.75 times higher odds.

However, among people who used any illicit drug, there was no significant difference in depression or suicidal thoughts between marijuana-only users and other drug users. Among marijuana users, frequency of use correlated with suicidal thoughts only in those who already had major depression.

Why it matters

As the population ages and cannabis use among older adults increases, understanding the mental health associations in this age group becomes important. This is one of relatively few studies to focus specifically on marijuana and mental health in adults over 50.

The numbers in context

29,634 individuals aged 50+. Nearly 6% reported past-year illicit drug use. Marijuana-only vs. non-users: OR 1.54 for depression. Other drugs only: OR 2.75. Both: OR 2.12. Suicidal thoughts among marijuana+other drug users: OR 2.44.

How the study worked

Analysis of the 2008-2012 National Survey on Drug Use and Health (NSDUH), a nationally representative US survey. The sample included 29,634 individuals aged 50+. Logistic regression was used to test associations between drug use and mental health outcomes.

What this study cannot tell us

Cross-sectional design cannot determine whether marijuana use contributes to depression or whether depressed older adults are more likely to use marijuana. Self-reported drug use may be underreported. The study could not distinguish between medical and recreational cannabis use.

How to read the evidence

This is a large national survey analysis providing moderate evidence on associations, though the cross-sectional design limits causal inference.

When this study was published

Published in 2016, using 2008-2012 data. Cannabis use among older adults has continued to increase since then.

The bigger picture

The growing population of older cannabis users is an understudied group. This study suggests that marijuana use among older adults is associated with mental health concerns, but the association is weaker than for other illicit drugs and is complicated by the high correlation between marijuana use and broader patterns of substance use.

Questions still open

Are older adults using cannabis to self-medicate depression? Would the associations hold if medical cannabis users were analyzed separately?

Common questions

Is marijuana more dangerous for older adults' mental health?

This study found an association between marijuana use and depression in adults over 50, but the association was weaker than for other illicit drugs. The cross-sectional design cannot determine whether marijuana caused the depression or whether depressed adults were more likely to use cannabis.

Does frequency of marijuana use matter for suicide risk?

Among marijuana users over 50, frequency of use was associated with suicidal thoughts only in those who already had major depression. For those without depression, marijuana use frequency was not significantly linked to suicidal thoughts.

Read the original research

Relationship between marijuana and other illicit drug use and depression/suicidal thoughts among late middle-aged and older adults.

International psychogeriatrics, 28(4), 577-89

View on PubMed ↗Publisher’s paper ↗

Citation

Choi, Namkee G; DiNitto, Diana M; Marti, C Nathan; Choi, Bryan Y. (2016). Relationship between marijuana and other illicit drug use and depression/suicidal thoughts among late middle-aged and older adults.. International psychogeriatrics, 28(4), 577-89. https://doi.org/10.1017/S1041610215001738