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Study breakdown

Poor Diet, Sitting, Cannabis, and Tobacco Are All Equally Linked to Mental Health Disorders

evidence
The takeaway

Poor diet, sedentary behavior, cannabis use, and tobacco use are approximately equally strongly associated with a range of mental health disorders, suggesting shared underlying causes.

Psychiatrists, public health researchers, and behavioral health program designers.

294 studies reviewed

finding approximately equal associations between 4 unhealthy behaviors and 7 mental health disorders

What the researchers found

Across 294 studies, four unhealthy behaviors were about equally associated with psychosis, depression, anxiety, bipolar disorder, ADHD, and PTSD. Only cannabis-personality disorder was exceptionally strong.

Why it matters

The equal strength of these associations suggests they reflect a general vulnerability rather than specific substance effects, which has implications for prevention and treatment approaches.

The numbers in context

294 studies from 3,682 records. Associations examined for 4 behaviors x 7 disorders. Cannabis-personality disorder association was uniquely strong. Findings robust across sensitivity analyses.

How the study worked

Systematic comparative review of odds ratios from studies published since 2015, with sensitivity analyses for sample bias, measurement disparities, and control variables.

Who was studied

Diverse populations across 294 studies covering multiple mental health disorders.

What this study cannot tell us

Heterogeneous methodologies across included studies. Odds ratios only; other effect measures excluded. Explorative rather than definitive analysis. Many studies cross-sectional.

How to read the evidence

Large systematic comparative review with sensitivity analyses; explorative findings need confirmation.

When this study was published

Reviews studies from 2015 onward.

The bigger picture

If unhealthy behaviors and mental disorders share a general etiology, interventions addressing one behavior may benefit mental health broadly, and conversely, treating mental disorders may reduce unhealthy behaviors.

Replication

Explorative comparative review; comprehensive confirmatory analysis recommended by authors.

Funding

Not specified in abstract

Conflicts of interest

Not specified in abstract

Questions still open

  • What is the shared etiology connecting these behaviors and disorders?
  • Should mental health treatment routinely address all four behavior domains?

Read the original research

Unhealthy behaviors associated with mental health disorders: a systematic comparative review of diet quality, sedentary behavior, and cannabis and tobacco use.

Frontiers in public health, 11, 1268339

Citation

Johnstad, Petter Grahl. (2023). Unhealthy behaviors associated with mental health disorders: a systematic comparative review of diet quality, sedentary behavior, and cannabis and tobacco use.. Frontiers in public health, 11, 1268339. https://doi.org/10.3389/fpubh.2023.1268339