Cannabis use was associated with slower response times on attention tasks in adolescents and young adults, and subclinical ADHD symptoms did not explain or modify this relationship.
Young cannabis users, parents, and clinicians evaluating attention problems in adolescents.
ADHD symptoms did not explain cannabis attention deficits
What the researchers found
Cannabis users demonstrated significantly slower hit rate response on the Continuous Performance Test (CPT), an attention task. Subclinical ADHD symptoms (measured by parent report) did not independently predict any attention deficits and did not moderate the effects of cannabis use on attention.
Why it matters
The suggestion that attention problems in cannabis users might simply reflect underlying ADHD is common. This study challenges that narrative by showing the deficits persist after accounting for subclinical ADHD.
The numbers in context
72 participants (34 cannabis users, 38 controls). Cannabis use significantly predicted slower CPT hit rate. ADHD symptoms did not predict any cognitive outcomes.
How the study worked
Cross-sectional study of 72 participants (34 cannabis users, 38 controls) aged adolescents and young adults. Neuropsychological tasks of inhibition and attention were administered. ADHD symptoms assessed by parent report on the Child Behaviors Checklist.
What this study cannot tell us
Small sample size. Cross-sectional design. ADHD symptoms were subclinical (participants with diagnosed ADHD were excluded). Parent-reported ADHD symptoms may underestimate actual symptoms in this age group.
How to read the evidence
Small cross-sectional study that cannot establish causation, but usefully controlled for a common confounder.
When this study was published
2019 study.
The bigger picture
Ruling out subclinical ADHD as an explanation for cannabis-related attention deficits strengthens the case that cannabis use itself contributes to these cognitive effects.
Questions still open
- Do these attention deficits resolve with sustained abstinence? Would findings differ in participants with diagnosed ADHD?
Common questions
Does cannabis cause attention problems or is it ADHD?
What attention problems do cannabis users have?
Read the original research
Effects of Cannabis Use and Subclinical ADHD Symptomology on Attention Based Tasks in Adolescents and Young Adults.
Archives of clinical neuropsychology : the official journal of the National Academy of Neuropsychologists, 34(5), 700-705
Citation
Wallace, Alexander L; Wade, Natasha E; Hatcher, Kelah F; Lisdahl, Krista M. (2019). Effects of Cannabis Use and Subclinical ADHD Symptomology on Attention Based Tasks in Adolescents and Young Adults.. Archives of clinical neuropsychology : the official journal of the National Academy of Neuropsychologists, 34(5), 700-705. https://doi.org/10.1093/arclin/acy080
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