More Cannabis Use Linked to Modest Cognitive Dips in Young Adults | Research

The takeaway

Among 225 young adults, greater cannabis use frequency was associated with small reductions in emotional processing speed and working memory, with modest additional effects of earlier onset but no sex differences.

Neuropsychologists, youth substance use researchers, and young adults

Small but significant cognitive effects with no sex differences

What the researchers found

Greater past 6-month cannabis use was associated with poorer Emotional Stroop Congruent Accuracy (p=0.0004) and List Sorting Working Memory performance (p=0.02, marginally significant after correction). Younger age of regular use onset was modestly related to lower Stroop accuracy (p=0.03, marginally significant). No cannabis-by-sex interactions were found.

Why it matters

The small but significant effects on processing speed and working memory add to the literature on cannabis cognition, while the lack of sex differences pushes back against the assumption that males and females are differentially affected.

The numbers in context

225 young adults ages 16-22. Emotional Stroop Congruent Accuracy: p=0.0004 (FDR-p=0.002). Working Memory: p=0.02 (FDR-p=0.10, marginal). Age of onset and Stroop: p=0.03 (FDR-p=0.13, marginal). No sex interactions on any cognitive measure.

How the study worked

Cross-sectional study of 225 young adults ages 16-22 who completed substance use interviews and a cognitive battery including the Emotional Word-Emotional Face Stroop and NIH Toolbox executive functioning tasks. Linear regressions with FDR correction for multiple comparisons.

What this study cannot tell us

Cross-sectional design cannot determine if cannabis causes cognitive effects or if pre-existing differences drive both use and performance. Small sample. Multiple comparisons reduce confidence in marginal findings. Self-reported cannabis use and other substance use.

How to read the evidence

Adequate sample with validated cognitive measures and FDR correction, though cross-sectional design limits causal inference.

When this study was published

2024 study

The bigger picture

The effect sizes are small, consistent with the broader literature showing cannabis-related cognitive effects are detectable but modest in young adults. This suggests cannabis does not cause dramatic cognitive impairment but may create subtle disadvantages.

Questions still open

Would the cognitive effects reverse with abstinence? Do the small effects compound over time with continued use? Are the emotional processing effects related to cannabis's impact on anxiety-related brain circuits?

Common questions

Does cannabis affect cognition in young adults?

This study found small but statistically significant reductions in emotional processing speed and working memory associated with more cannabis use. The effects were modest, consistent with the broader literature.

Does starting cannabis younger make cognitive effects worse?

Modestly. Earlier age of regular use was associated with slightly lower processing speed, but the effect was marginally significant after statistical correction and needs confirmation in larger studies.

Read the original research

Investigating sex differences and age of onset in emotion regulation, executive functioning, and cannabis use in adolescents and young adults.

Journal of cannabis research, 6(1), 20

View on PubMed ↗Publisher’s paper ↗

Citation

Wade, Natasha E; Courtney, Kelly E; Wallace, Alexander L; Hatz, Laura; Jacobus, Joanna. (2024). Investigating sex differences and age of onset in emotion regulation, executive functioning, and cannabis use in adolescents and young adults.. Journal of cannabis research, 6(1), 20. https://doi.org/10.1186/s42238-024-00225-z