Female Sex as a Protective Factor in the Effects of Chronic Cannabis Use on Verbal Learning and Memory

Sex differences in the prospective association of excessively long reaction times and hazardous cannabis use at six months

Objective

The neurocognitive risk mechanisms predicting divergent outcomes likely differ between men and women who use cannabis recreationally. Increasingly, the use of descriptive distributions including the ex-Gaussian has been applied to draw stronger inferences about neurocognitive health in clinical populations. The current project examines whether the long tail of reaction times (RTs) in a distribution, as characterized by the ex-Gaussian parameter tau which may represent difficulty with the regulation of arousal, predicts problematic cannabis use 6 months later in those who use cannabis recreationally, and whether sex moderates these prospective associations.

Method

Young adults (ages 18-30, mean age 20.5 years, N =159, 57.2% women, 69.2% Caucasian) who recreationally used cannabis either occasionally (at least once per month) or frequently (three times or more per week) completed the Stroop Color-Word Task at baseline. Ex-Gaussian parameter tau was estimated for each participant. Self-report of hazardous cannabis use (CUDIT-R) and dysregulation of negative (DERS) and positive emotions (DERS-Positive) were obtained at baseline and 6-month follow-up.

Results

For those with larger tau at baseline, being a man (but not a woman) was associated with increased difficulty regulating positive emotions concurrently (b = -0.01, F (1,159) = 5.48, p = 0.02), and with hazardous cannabis use six months later (b = -0.007, F (1,159) = 4.42, p = 0.037) after controlling for baseline hazardous cannabis use.

Conclusions

Excessively long RTs during cognitive performance may help characterize men at risk for increased hazardous use, which contributes to understanding between-sex heterogeneity in pathways towards cannabis use disorders.

A preliminary investigation of sex differences in cognitive and fMRI changes following 28 days of cannabis abstinence

BACKGROUND

Previous studies have investigated the influence of cannabis on cognition among people with MS (pwMS), yet the influence of sex in the context of cannabis use remains unexplored. We aim to fill this gap by investigating cannabis-sex related differences in verbal learning, memory and processing speed in association with fMRI (resting state, and task-based) metrics.

METHOD

Our sample consisted of 19 long-term, frequent cannabis users (8 males, 11 females). Assessments were conducted at baseline and after 28 days of cannabis abstinence. The tests included measures of verbal memory (Selective Reminding Test (SRT)), working memory (n-back), information processing speed (Symbol Digit Modalities Test (SDMT)) and the resting state DMN. To evaluate the effects of cannabis abstinence, we performed a group x time interaction analysis using repeated measures ANCOVA. This analysis controlled for several covariates, including the level of disability (EDSS), baseline cannabis THC metabolite levels, and cannabis withdrawal symptoms. By controlling for these variables, we aimed to isolate the impact of cannabis abstinence on cognitive performance over time. Statistical significance was set at p < 0.05.

RESULTS

There were no baseline cognitive differences between the sexes. After 28 days of cannabis abstinence, females performed better on the Selective Reminding Test (SRT) (p = 0.04), with a large effect size (η² = 0.286). The mean correct response improved over time for females, but there was no statistically significant group x time interaction on the Symbol Digit Modalities Test (SDMT) and the n-back task. Resting state default mode network data showed overall increased activation in females relative to males at day 28, which meshed with lower brain activation during task-based fMRI paradigms.

CONCLUSION

Cannabis negated sex-based cognitive differences. Functional MRI task-based paradigms revealed less cerebral activation in females compared to males, which was associated with comparable or better cognitive performance in females, particularly after cannabis abstinence.

Sex Differences in the Association Between Cumulative Use of Cannabis and Cognitive Function in Middle Age: The Coronary Artery Risk Development in Young Adults Study

Background: Cannabis use may impair cognitive function (CF) differently in men and women, due to sex-specific differences in neurobiological mechanisms and environmental risk factors. Objective: Assess sex differences in the association between cumulative exposure to cannabis and cognitive performance in middle age. Methods: We studied participants from the Coronary Artery Risk Development in Young Adults (CARDIA) Study, including Black and White men and women 18-30 years old at baseline followed over 30 years. Our cross-sectional analysis of CF scores at year 30 was stratified by sex. We computed categories of cumulative exposure in "cannabis-years" (1 cannabis-year=365 days of use) from self-reported use every 2 to 5 years over 30 years. At years 25 and 30, we assessed CF with the Rey Auditory Verbal Learning Test (verbal memory), the Digit Symbol Substitution Test (processing speed), and the Stroop Interference Test (executive function). At year 30, additional measures included Category and Letter Fluency Test (verbal ability) and the Montreal Cognitive Assessment (global cognition). We computed standardized scores for each cognitive test and applied multivariable adjusted linear regression models for self-reported cumulative cannabis use, excluding participants who used cannabis within 24 h. In a secondary analysis, we examined the association between changes in current cannabis use and changes in CF between years 25 and 30. Results: By year 30, 1,352 men and 1,793 women had measures of CF; 87% (N=1,171) men and 84% (N=1,502) women reported ever cannabis use. Men had a mean cumulative use of 2.57 cannabis-years and women 1.29 cannabis-years. Self-reported cumulative cannabis use was associated with worse verbal memory in men (e.g., -0.49 standardized units [SU] for ≥5 cannabis-years of exposure; 95% CI=-0.76 to -0.23), but not in women (SU=0.02; 95% CI=-0.26 to 0.29). Other measures of CF were not associated with cannabis. Changes in current cannabis use between years 25 and 30 were not associated with CF in men or women. Conclusions: Self-reported cumulative cannabis exposure was associated with worse verbal memory in men but not in women. Researchers should consider stratified analyses by sex when testing the association between cannabis and cognition.

The impact of recreational cannabis use on neuropsychological function in epilepsy

Cannabis use is associated with neuropsychological impairments in the general population, but little is known about the impact on cognitive function in people with epilepsy who are already at increased risk of difficulties due to the essential comorbidities of the disease. We compared the performance of 42 people with epilepsy (PWE) who reported regular cannabis use with 254 age matched, non-cannabis-using PWE. Patients completed tests of intellectual reserve, memory, language and processing speed. Approximately one in 17 patients (5.9 %) reported current cannabis use. Cannabis use was not associated with epilepsy type. Males were 1.8 times more likely to report cannabis use compared to females. Cannabis use was associated with lower intellectual reserve (Reading IQ: t = 2.8, p < 0.01, Cohen's d = 0.49), reduced encoding of new information (List Learning: t = 3.3, p < 0.001, Cohen's d = 0.56) and enhanced susceptibility to distraction on a subsequent recall task (t = 3.07, p < 0.01, Cohen's d = 0.51. In regression models cannabis use was significantly associated with impairments in learning and recall after controlling for elevated levels of anxiety and depression. Our data indicates that recreational cannabis use in people with epilepsy amplifies deficits in new learning and enhances susceptibility to distraction in the retention of newly learnt material. Recreational cannabis use should be considered when interpreting the significance of these cognitive impairments when they are recorded in a clinical assessment.