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Study breakdown

Cannabis Affects Male and Female Brains Differently on Cognitive Tests

Cross SectionalModerate evidence
The takeaway

Among 171 regular cannabis users aged 13-25, males showed poorer visual memory while females had worse attention and executive function, suggesting sex-specific cognitive vulnerabilities.

Adolescent health researchers, neuropsychologists, substance use counselors

Earlier cannabis initiation was linked to worse attention in females but not males

What the researchers found

Male cannabis users had poorer visual recognition memory while female users showed worse attention and executive functioning (medium to large effect sizes), with earlier initiation and heavier use more strongly linked to attention deficits in females and memory/learning deficits in males.

Why it matters

If cannabis affects cognitive domains differently by sex, prevention messaging and clinical monitoring may need to be tailored rather than one-size-fits-all.

The numbers in context

171 participants; 46.2% female; aged 13-25; medium to large effect sizes for sex differences; earlier initiation associated with worse attention in females but not males; heavier use linked to worse episodic memory and learning in males.

How the study worked

Cross-sectional study of 171 at-least-weekly cannabis users aged 13-25 (46.2% female) using the Cambridge Neuropsychological Test Automated Battery (CANTAB), controlling for age, IQ, alcohol, nicotine, mood, and impulsivity.

What this study cannot tell us

No healthy control group for comparison; cross-sectional design prevents causal inference; cannot determine if sex differences are more pronounced than in non-users; potential selection bias.

How to read the evidence

Moderate-sized cross-sectional study with validated cognitive testing battery, limited by lack of control group and cross-sectional design.

When this study was published

Published in 2021 with participants aged 13-25.

The bigger picture

These domain-specific sex differences in cannabis-related cognitive effects mirror broader neuroscience findings about sex differences in brain development during adolescence, suggesting cannabis may interact with sex-specific developmental trajectories.

Questions still open

  • Do these sex-specific cognitive differences persist after sustained abstinence? Would including a control group reveal whether cannabis exaggerates pre-existing sex differences in cognition?

Common questions

Does cannabis affect boys and girls differently?
In this study of 171 regular users aged 13-25, males showed poorer visual memory while females had worse attention and executive function, suggesting the cognitive effects of cannabis differ by sex.
Does starting younger make the effects worse?
For females, earlier age of first use was associated with worse attentional function. For males, heavier use was more strongly linked to memory and learning deficits.

Read the original research

Sex Differences in Neuropsychological Functioning are Domain-Specific in Adolescent and Young Adult Regular Cannabis Users.

Journal of the International Neuropsychological Society : JINS, 27(6), 592-606

Citation

Savulich, George; Rychik, Natali; Lamberth, Erin; Hareli, Maya; Evins, A Eden; Sahakian, Barbara J; Schuster, Randi M. (2021). Sex Differences in Neuropsychological Functioning are Domain-Specific in Adolescent and Young Adult Regular Cannabis Users.. Journal of the International Neuropsychological Society : JINS, 27(6), 592-606. https://doi.org/10.1017/S1355617720001435

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