Among Heavy Cannabis Users, Depression and Suicidal Behavior Were Linked to Parental Alcoholism, Not Cannabis Itself | Research

The takeaway

A study of 119 heavy cannabis users seeking treatment found high rates of depression (46%), suicidal ideation (42%), and suicidal behavior (23%), but these were predicted by parental alcoholism and adverse childhood experiences rather than by cannabis or other drug use.

Read this if you want to understand what drives depression and suicidality in heavy cannabis users.

Parental alcoholism, not cannabis use, predicted depression and suicidality in heavy users

What the researchers found

Researchers assessed 119 heavy cannabis users recruited from 19 substance treatment centers in Denmark. Depression, suicidal ideation, and suicidal behavior were highly prevalent: 46% had lifetime depression, 42% reported suicidal ideation, and 23% had engaged in suicidal behavior.

These problems were more common among females and were significantly associated with adverse childhood experiences and parental alcoholism. Critically, comorbid alcohol or other drug use did not independently increase the risk.

Parental alcoholism remained significantly associated with depression (P < 0.009), suicidal ideation (P < 0.001), and suicidal behavior (P < 0.03) even after adjusting for multiple potential confounders. Physical abuse during childhood independently predicted suicidal ideation (P < 0.01).

Why it matters

This study suggests that the high rates of depression and suicidality seen among heavy cannabis users may be driven more by childhood adversity and family factors than by cannabis use itself. This has implications for treatment: addressing underlying trauma and family history may be more important than focusing solely on cannabis cessation.

The numbers in context

119 heavy cannabis users from 19 treatment centers. Depression: 46%. Suicidal ideation: 42%. Suicidal behavior: 23%. Parental alcoholism predicted: depression (P < .009), suicidal ideation (P < .001), suicidal behavior (P < .03). Physical abuse predicted suicidal ideation (P < .01).

How the study worked

Cross-sectional study of 119 subjects from 19 Danish substance treatment centers. Structured questionnaires and SCAN psychiatric assessment, Beck Depression Inventory, Addiction Severity Index, CIDI, and AUDIT administered.

What this study cannot tell us

Treatment-seeking population may not represent all heavy cannabis users. Cross-sectional design cannot establish causation. Self-reported childhood experiences may be affected by current mental state (depressed individuals may recall more negative experiences). The sample was entirely from Denmark.

How to read the evidence

Cross-sectional study from multiple treatment centers with standardized psychiatric assessment. Identifies important predictors but cannot establish causation.

When this study was published

Published in 2007. Research on childhood adversity and substance use has expanded substantially, generally supporting the role of early-life factors.

The bigger picture

The finding that family and childhood factors, rather than substance use itself, predicted mental health problems in heavy cannabis users supports a more nuanced understanding of co-occurring disorders. It suggests shared risk factors drive both cannabis use and mental health problems rather than one causing the other.

Questions still open

Would addressing childhood trauma in cannabis treatment programs improve outcomes? Does parental alcoholism create genetic vulnerability, environmental risk, or both for cannabis users' mental health problems?

Common questions

Does heavy cannabis use cause depression and suicidal thoughts?

In this study, the depression and suicidality seen in heavy cannabis users were predicted by parental alcoholism and childhood adversity rather than by cannabis or other drug use. This suggests shared risk factors rather than cannabis directly causing these mental health problems.

How common is depression among heavy cannabis users?

In this treatment-seeking sample, 46% had lifetime depression, 42% reported suicidal ideation, and 23% had engaged in suicidal behavior. These rates are much higher than the general population but appear driven by childhood and family factors.

Read the original research

Parental alcoholism predicts suicidal behavior in adolescents and young adults with cannabis dependence.

International journal of adolescent medicine and health, 19(1), 67-77

View on PubMed ↗

Citation

Arendt, Mikkel; Sher, Leo; Fjordback, Lone; Brandholdt, Jack; Munk-Jorgensen, Povl. (2007). Parental alcoholism predicts suicidal behavior in adolescents and young adults with cannabis dependence.. International journal of adolescent medicine and health, 19(1), 67-77.