Individual prolactin reactivity modulates response of nucleus accumbens to erotic stimuli during acute cannabis intoxication: an fMRI pilot study

Considering hormones as sex- and gender-related factors in biomedical research: Challenging false dichotomies and embracing complexity

The inclusion of sex and gender considerations in biomedicine has been increasing in light of calls from research and funding agencies, governmental bodies, and advocacy groups to direct research attention to these issues. Although the inclusion of both female and male participants is often an important element, overreliance on a female-male binary tends to oversimplify the interactions between sex- and gender-related factors and health, and runs a risk of being influenced by cultural stereotypes about sex and gender. When biomedical researchers are examining how hormones associated with gender and sex may influence pathways of interest, it is of crucial importance to approach this work with a critical lens on the rhetoric used, and in ways that acknowledge the complexity of hormone physiology. Here, we document the ways in which discourses around sex, gender and hormones shape our scientific thinking and practice in biomedical research, and review how the existing scientific knowledge about hormones reflects a complex and dynamic reality that is often not reflected outside of specialist niches of hormone biology. Where biomedical scientists take up sex- and gender-associated hormones as a way of addressing sex and gender considerations, it is valuable for us to bring a critical lens to the rhetoric and discourses used, to employ a sex contextualist approach in designing experimentation, and be rigorous and reflexive about the approaches used in analysis and interpretation of data. These strategies will allow us to design experimentation that goes beyond binaries, and grapples more directly with the material intricacies of sex, gender, and hormones.

Causal relationship between cannabis use and cancer: a genetically informed perspective

PURPOSE

Cannabis use is increasing legally worldwide, while its impact on cancer risk is unclear. This study was performed to investigate the relationship between cannabis use and the risk of several types of cancer.

METHODS

We conducted a two-sample Mendelian randomization (MR) study to explore the causality of cannabis use on 9 site-specific types of cancer including breast cancer, cervical cancer, melanoma, colorectal cancer, laryngeal cancer, oral cancer, oropharyngeal cancer, esophageal cancer, and glioma. Genome-wide significant genetic instruments (P < 5E-06) for cannabis use were extracted from a large-scale genome-wide association meta-analysis of European ancestry, whereas cancer genetic instruments were extracted from the UK Biobank (UKB) cohort and GliomaScan consortium in the OpenGWAS database. The inverse-variance weighted (IVW) was considered the main method for MR analysis, and sensitivity analyses including MR-Egger, weighted median, MR pleiotropy residual sum, and outlier test (MR-PRESSO) were conducted to evaluate the robustness of the results.

RESULTS

Cannabis use was a significant promoting factor for cervical cancer (OR = 1.001265, 95% CI 1.000375-1.002155, P = 0.0053). And we also detected suggestive evidence of the causality of cannabis use on laryngeal cancer (OR = 1.000350, 95% CI 1.000027-1.000672, P = 0.0336) and breast cancer (OR = 1.003741, 95% CI 1.000052-1.007442, P = 0.0467). No evidence of a causal association of cannabis use with other site-specific types of cancer was detected. Additionally, no pleiotropy or heterogeneity was found in the sensitivity analysis.

CONCLUSION

This study indicates a causative association of cannabis use on cervical cancer, while cannabis use may increase the odds of breast cancer and laryngeal cancer, which require further evaluation in large-scale population-based studies.

Geospatiotemporal and causal inference study of cannabis and other drugs as risk factors for female breast cancer USA 2003-2017

Breast cancer (BC) is the commonest human cancer and its incidence (BC incidence, BCI) is rising worldwide. Whilst both tobacco and alcohol have been linked to BCI genotoxic cannabinoids have not been investigated. Age-adjusted state-based BCI 2003-2017 was taken from the Surveillance Epidemiology and End Results database of the Centers for Disease Control. Drug use from the National Survey of Drug Use and Health, response rate 74.1%. Median age, median household income and ethnicity were from US census. Inverse probability weighted (ipw) multivariable regression conducted in R. In bivariate analysis BCI was shown to be significantly linked with rising cannabis exposure {β-est. = 3.93 [95% confidence interval 2.99, 4.87], P = 1.10 × 10-15}. At 8 years lag cigarettes:cannabis [β-est. = 2660 (2150.4, 3169.3), P = 4.60 × 10-22] and cannabis:alcoholism [β-est. = 7010 (5461.6, 8558.4), P = 1.80 × 10-17] were significant in ipw-panel regression. Terms including cannabidiol [CBD; β-est. = 16.16 (0.39, 31.93), P = 0.446] and cannabigerol [CBG; β-est. = 6.23 (2.06, 10.39), P = 0.0034] were significant in spatiotemporal models lagged 1:2 years, respectively. Cannabis-liberal paradigms had higher BCI [67.50 ± 0.26 v. 65.19 ± 0.21/100 000 (mean ± SEM), P = 1.87 × 10-11; β-est. = 2.31 (1.65, 2.96), P = 9.09 × 10-12]. 55/58 expected values >1.25 and 13/58 >100. Abortion was independently and causally significant in space-time models. Data show that exposure to cannabis and the cannabinoids Δ9-tetrahydrocannabinol, CBD, CBG and alcoholism fulfil quantitative causal criteria for BCI across space and time. Findings are robust to adjustment for age and several known sociodemographic, socio-economic and hormonal risk factors and establish cannabinoids as an additional risk factor class for breast carcinogenesis. BCI is higher under cannabis-liberal legal paradigms.

A review of the effects of acute and chronic cannabinoid exposure on the stress response

While cannabis has been used for centuries for its stress-alleviating properties, the effects of acute and chronic cannabinoid exposure on responses to stress remain poorly understood. This review provides an overview of studies that measured stress-related endpoints following acute or chronic cannabinoid exposure in humans and animals. Acute cannabinoid exposure increases basal concentrations of stress hormones in rodents and humans and has dose-dependent effects on stress reactivity in humans and anxiety-like behavior in rodents. Chronic cannabis exposure is associated with dampened stress reactivity, a blunted cortisol awakening response (CAR), and flattened diurnal cortisol slope in humans. Sex differences in these effects remain underexamined, with limited evidence for sex differences in effects of cannabinoids on stress reactivity in rodents. Future research is needed to better understand sex differences in the effects of cannabis on the stress response, as well as downstream impacts on mental health and stress-related disorders.

A Survey Exploring the Relationship Between Cannabis Use Characteristics and Sexual Function in Men

Introduction

Cannabis is the most commonly used drug in the United States; however, the effects of cannabis use on male sexual function are poorly understood.

Aim

To characterize the contemporary landscape of cannabis use and to assess the associations between male sexual function and the frequency of use, the primary method of consumption, or cannabis chemovar (tetrahydrocannabinol or cannabidiol) among current users.

Methods

We surveyed adults who visited a single cannabis dispensary for baseline demographic information, medical history, cannabis use habits, and sexual function as assessed by the International Index of Erectile Function (IIEF). An IIEF-5 < 21 was considered erectile dysfunction.

Main Outcome Measures

The main outcome measure of the study was male sexual function via the IIEF domain scores.

Results

A total of 325 men completed the survey with a mean age of 46.7 years. 71.1% of the men were Caucasian and 52.6% were married. 13 men (4%) were never users; 29 men (8.9%) used 1–2 times/week; 51 men (15.7%) used 3–5 times/week, and 232 men (71.4%) used 6+ times/week. The average IIEF-5 score was 22.3 with 19.4% of the men having erectile dysfunction. In univariate analysis, men using cannabis more frequently had a higher overall IIEF (65.36 vs 60.52, P = .001), erectile domain (27.32 vs 25.74, P = .03), orgasm domain (9.08 vs 8.12, P < .001), intercourse satisfaction domain (12.42 vs 11.31, P = .006), and overall satisfaction domain (8.11 vs 7.05, P = .002). In multivariable analysis, compared to men who used cannabis 0 times/week, those who used 6 times/week had an increased overall IIEF (69.08 vs 64.64, P-value adjusted = 0.02), intercourse satisfaction domain (P-value adjusted = 0.04), and overall satisfaction domain (P-value adjusted = 0.02). The primary method of consumption (eg, smoking, edibles, etc.) and cannabinoid composition (eg, cannabidiol vs tetrahydrocannabinol dominant) were not associated with sexual function.

Conclusion

We report an association between the increased frequency of cannabis use and increased male sexual function. However, while the increased frequency of use was statistically significant with regard to the IIEF scores, the clinical significance of this is likely low, and selection bias may limit the generalizability of these findings. The method of consumption and cannabis chemovar were not associated with sexual function.

Bhambhvani HP, Kasman AM, Wilson-King G, et al. A Survey Exploring the Relationship Between Cannabis Use Characteristics and Sexual Function in Men. J Sex Med 2020;8:436–445.

Cannabis and Male Fertility: A Systematic Review

PURPOSE

With cannabis consumption on the rise and use prominent among males of reproductive age it is essential to understand the potential impact of cannabis on male fertility. We reviewed the literature regarding the effects of cannabis on male fertility.

MATERIALS AND METHODS

We performed a literature search using PubMed®/MEDLINE® to identify relevant studies of the effects of cannabis on male fertility. Relevant studies were identified and reviewed.

RESULTS

The strongest evidence of cannabis induced alterations in male fertility is in the category of semen parameters. Research supports a role for cannabis in reducing sperm count and concentration, inducing abnormalities in sperm morphology, reducing sperm motility and viability, and inhibiting capacitation and fertilizing capacity. Animal models demonstrate a role for cannabis in testicular atrophy, and reduced libido and sexual function but to our knowledge these results have not yet been replicated in human studies. Studies of hormonal changes suggest inconclusive effects on testosterone levels, lowered luteinizing hormone levels and unchanged follicle-stimulating hormone levels.

CONCLUSIONS

Current research suggests that cannabis may negatively impact male fertility. Further studies are needed to validate that robust findings in animal models will carry over into human experience. Clinicians should be aware of these potential effects when prescribing medical marijuana therapies to men of reproductive age, and they should consider the degree of cannabis use as a possible component of a complete male infertility workup.

Cannabis-induced altered states of consciousness are associated with specific dynamic brain connectivity states

BACKGROUND

Cannabis, and specifically one of its active compounds delta-9-tetrahydrocannabinol in recreational doses, has a variety of effects on cognitive processes. Most studies employ resting state functional magnetic resonance imaging techniques to assess the stationary effects of cannabis and to-date one report addressed the impact of delta-9-tetrahydrocannabinol on the dynamics of whole-brain functional connectivity.

METHODS

Using a repeated-measures, within-subjects design, 19 healthy occasional cannabis users (smoking cannabis ⩽2 per week) underwent resting state functional magnetic resonance imaging scans. Each subject underwent two scans: in the intoxicated condition, shortly after smoking a cannabis cigarette, and in the non-intoxicated condition, with the subject being free from cannabinoids for at least one week before. All sessions were randomized and performed in a four-week interval. Data were analysed employing a standard independent component analysis approach with subsequent tracking of the functional connectivity dynamics, which allowed six connectivity clusters (states) to be individuated.

RESULTS

Using standard independent component analysis in resting state functional connectivity, a group effect was found in the precuneus connectivity. With a dynamic independent component analysis approach, we identified one transient connectivity state, characterized by high connectivity within and between auditory and somato-motor cortices and anti-correlation with subcortical structures and the cerebellum that was only found during the intoxicated condition. Behavioural measures of the subjective experiences of changed perceptions and tetrahydrocannabinol plasma levels during intoxication were associated with this state.

CONCLUSIONS

With the help of the dynamic connectivity approach we could elucidate neural correlates of the transitory perceptual changes induced by delta-9-tetrahydrocannabinol in cannabis users, and possibly identify a biomarker of cannabis intoxication.

Marijuana Use and Hypothalamic-Pituitary-Adrenal Axis Functioning in Humans

Preclinical studies suggest cannabinoids affect functioning of the hypothalamic-pituitary-adrenal (HPA) axis, but little is known about the effects of marijuana (MJ) use on HPA axis functioning in humans. Since previous work indicates substances of abuse may dysregulate the HPA axis, it is critical to understand how MJ use affects HPA axis activity. Here, we review studies that (a) examined the effects of acute MJ administration on HPA axis functioning, (b) investigated the impact of stress on HPA axis functioning in MJ users, (c) examined the effect of chronic MJ use on basal cortisol levels, and (d) studied the relationship between MJ use and the cortisol awakening response (CAR). Findings indicate acute MJ administration typically raises cortisol levels, but this increase is blunted in MJ-dependent users relative to controls. Frequent MJ users have blunted adrenocorticotropic hormone and cortisol reactivity in response to acute stress. These findings suggest HPA axis activity may be dysregulated by heavy MJ use. Alternatively, dysregulation of the HPA axis may be a risk marker for heavy MJ use. There is mixed evidence for how MJ use affects basal cortisol levels and the CAR. Future studies should consider MJ use characteristics, method of hormone collection, time when samples are collected, and environmental factors that may influence HPA axis activity in MJ users. By examining existing studies we provide one of the first reviews aimed at synthesizing the literature on HPA axis functioning in MJ users.