Earlier cannabis use was linked to worse memory in young women but not men | Research

The takeaway

Among 69 young adult cannabis users, earlier initiation of use was associated with poorer episodic memory in females but not males, suggesting sex-specific cognitive vulnerabilities.

Read this if you're interested in whether cannabis affects young men and women differently.

Earlier use linked to worse memory in females, not males

What the researchers found

Researchers examined 44 male and 25 female young adult cannabis users to determine whether the age of first cannabis use affected cognitive function differently by sex. After controlling for total lifetime cannabis use, earlier initiation was associated with poorer episodic memory, particularly immediate recall, in females but not males.

Surprisingly, earlier initiation was associated with better decision-making overall, but exploratory analysis revealed this was driven by ADHD symptoms in females, suggesting a confound rather than a cannabis benefit. Earlier female initiators also had lower IQ, less education, and lower maternal education levels.

For males, earlier initiation was primarily associated with more lifetime cannabis use but not with neuropsychological differences after controlling for total exposure. The findings suggest males and females may have different risk profiles for cannabis-related cognitive effects.

Why it matters

Most cannabis research does not separate results by sex, potentially masking important differences. If females are more vulnerable to memory effects from early cannabis use, sex-specific prevention messaging and clinical guidance may be needed.

The numbers in context

44 males and 25 females studied. Earlier female initiators showed poorer immediate recall. Earlier initiation linked to lower IQ, less education in females. Earlier initiation linked to more lifetime use in males.

How the study worked

Cross-sectional neuropsychological study of 44 male and 25 female young adult cannabis users. Multiple cognitive domains were assessed after controlling for lifetime cannabis use. Sex-stratified analyses examined relationships between age of initiation and cognitive performance.

What this study cannot tell us

Small sample, especially for females (n=25). Cross-sectional design cannot establish causation. Earlier initiation was associated with multiple confounds (lower IQ, less education) that could explain cognitive differences. ADHD symptoms as a confound complicate decision-making findings.

How to read the evidence

Small cross-sectional study with sex-stratified analysis. Findings are preliminary and need larger replication studies.

When this study was published

Published in 2015. Sex differences in cannabis effects are increasingly studied.

The bigger picture

Adolescent brain development differs between males and females in timing and regional patterns. This study adds evidence that cannabis may interact differently with male and female brain development, which has implications for how risk is communicated to young people.

Questions still open

Are female brains more vulnerable to early cannabis exposure, or are other factors driving the association? Would a longitudinal study confirm these sex differences? Do these memory effects persist after cessation?

Common questions

Does cannabis affect men and women's brains differently?

This study found that starting cannabis use earlier was linked to worse memory in young women but not young men, suggesting possible sex-specific vulnerabilities. However, the sample was small and the study could not prove causation.

Does starting cannabis younger affect your memory?

For young women in this study, earlier initiation was associated with poorer episodic memory even after accounting for total lifetime use. For young men, earlier initiation was associated with using more cannabis overall but not with memory differences.

Read the original research

Neuropsychological sex differences associated with age of initiated use among young adult cannabis users.

Journal of clinical and experimental neuropsychology, 37(4), 389-401

View on PubMed ↗Publisher’s paper ↗

Citation

Crane, Natania A; Schuster, Randi Melissa; Mermelstein, Robin J; Gonzalez, Raul. (2015). Neuropsychological sex differences associated with age of initiated use among young adult cannabis users.. Journal of clinical and experimental neuropsychology, 37(4), 389-401. https://doi.org/10.1080/13803395.2015.1020770