Effect of alcohol, tobacco, and cannabis co-use on gray matter volume in heavy drinkers

Association Between Cannabis Use and Brain Structures: A Mendelian Randomization Study

Background  Observational studies suggested that cannabis use was associated with alternation of brain structures; however, as subjected to confounding factors, they were difficult to make causal inferences and direction determinations. In this study, a two-sample Mendelian randomization (MR) analysis was employed to examine the potential causal association between cannabis use and brain structures. Methods The genome-wide association studies (GWAS) data for lifetime cannabis use (LCU), cannabis use disorder (CUD), and brain cortical and subcortical structures were utilized in this study. Cortical structures were divided into 34 distinct gyral-defined regions with surface area (SA) and thickness (TH) measured. Subcortical structures encompassed volumes from seven specified regions. The primary estimator used in our analysis was inverse-variance weighted (IVW), complemented by MR-Egger and weighted median methods to enhance the robustness of the results. The Cochran's Q test, funnel plots, and MR-Egger intercept tests were used to detect heterogeneity and pleiotropy. Results  No causal relationship was detected between LCU and global cortical SA or TH. However, at the regional cortex level, LCU was associated with decreased TH in the fusiform (β = -0.0168 mm, SE = 0.00581, P = 0.0039) and lateral occipital (β = -0.0141 mm, SE = 0.00531, P = 0.0079) regions, while increasing TH in the postcentral region (β = 0.0093 mm, SE = 0.00445, P = 0.0374). At the subcortical level, LCU was found to increase the brainstem volume (β = 0.224 mm3, SE = 0.09, P = 0.0128). CUD did not show any causal association with brain structure at either cortical or subcortical levels. Nonetheless, after applying multiple comparison corrections, the P values for the MR analysis of causal relationships between cannabis use and these brain structures did not meet the significance threshold. Conclusion  The evidence for cannabis use causally influencing brain structures is insufficient.

Regional cortical brain volumes at treatment entry relates to post treatment WHO risk drinking levels in those with alcohol use disorder

BACKGROUND

Abstinence following treatment for alcohol use disorder (AUD) is associated with significant improvements in psychiatric and physical health, however, recent studies suggest resumption of low risk levels of alcohol use can also be beneficial. The present study assessed whether post-treatment levels of alcohol use were associated with cortical brain volumedifferences at treatment entry.

METHODS

Individuals seeking treatment for AUD (n=75) and light/non-drinking controls (LN, n=51) underwent 1.5T magnetic resonance imaging. The volumes of 34 bilateral cortical regions of interest (ROIs) were quantitated via FreeSurfer. Individuals with AUD were classified according to post-treatment alcohol consumption using the WHO risk drinking levels (abstainers: AB; low risk: RL; or higher risk: RH). Regional volumes for AB, RL and RH, at treatment entry, were compared to LN.

RESULTS

Relative to LN, AB demonstrated smaller volumes in 18/68 (26%), RL in 24/68 (35%) and RH in 34/68 (50%) ROIs with the largest magnitude volume differences observed between RH and LN. RH and RL reported a higher frequency of depressive disorders than AB. Among RH and RL, level of depressive and anxiety symptomatology were associated with daily number of drinks consumed after treatment.

CONCLUSIONS

Volumetric differences, at treatment entry, in brain regions implicated in executive function and salience networks corresponded with post-treatment alcohol consumption levels suggesting that pre-existing differences in neural integrity may contribute to treatment outcomes. Depressive and anxiety symptomatology was also associated with brain morphometrics and alcohol use patterns, highlighting the importance of effectively targeting these conditions during AUD treatment.

The role of sex in daily levels of high-risk alcohol and cannabis co-use

Background

Co-use of alcohol and cannabis is highly prevalent and may be associated with negative outcomes. The intersection between alcohol and cannabis use remains poorly understood. The present study assessed this intersection and the moderating effects of sex on the daily levels of high-risk alcohol and cannabis co-use.

Methods

A secondary analysis of an experimental pharmacology study specifically designed to recruit individuals using both alcohol and cannabis was conducted. Thirty-three non-treatment seeking subjects (19 M/14F) reporting high-risk levels of alcohol and cannabis use completed a 30-day Timeline Follow-back (TLFB) assessment for alcohol and cannabis use, resulting in a total of N = 990 observations. Logistic models tested the probability of same day cannabis use as predicted by alcohol use (any use, total drinking, and binge drinking), sex, and alcohol use by sex interactions.

Results

Drinking any alcohol on a given day was associated with a significant increase in the likelihood of same-day cannabis use (b = 0.61, p = 0.001) as was amount of alcohol consumed on a given day (b = 0.083, p = 0.012). These relations were significantly moderated by sex (b = 1.58, p<0.001; b = 0.14, p = 0.044). Male-identifying individuals demonstrated an increased probability of concurrent cannabis use with any alcohol use on a given day, and this relationship increased linearly as the number of drinks consumed increased.

Conclusions

The present study investigated the patterns associated with co-using alcohol and cannabis in individuals reporting high-risk levels of both alcohol and cannabis use. The sex-dependent findings suggest that males are at higher risk for co-using alcohol and cannabis compared with females.

Associations of daily alcohol, cannabis, combustible tobacco, and e-cigarette use with same-day co-use and poly-use of the other substances

BACKGROUND

Young adults frequently use alcohol, cannabis, and tobacco together. Given the increased prevalence of e-cigarette use and recreational cannabis use, we investigated daily patterns of alcohol, cannabis, and tobacco use and distinguished combustible tobacco from e-cigarettes.

METHODS

Young adult college students (N=341) reporting past-month alcohol and cannabis use "at the same time so that their effects overlapped" completed two 28-day bursts of repeated daily surveys. Exposures were day- and person-level use of each substance. Outcomes were (1) same-day co-use of each remaining substance or (2) poly-use of the other substances.

RESULTS

Daily use of alcohol, cannabis, combustible cigarettes, and e-cigarettes increased the odds of same-day co-use of the other substances (except combustible tobacco with e-cigarettes) and each poly-use outcome. The influence of person-level substance use on daily substance use was less consistent. Only e-cigarette use increased the odds of daily alcohol use. Use of either tobacco product but not alcohol increased the odds of daily cannabis use. Person-level alcohol and cannabis use increased the odds of daily use of either tobacco product but use of one tobacco product was not associated with daily use of the other product.

CONCLUSIONS

These findings increase our understanding of emerging daily patterns of alcohol, cannabis, and tobacco co-use, and the impact of different tobacco products. Future work is needed to extend this research into non-college samples and people who use tobacco but do not use alcohol and cannabis simultaneously, and examine daily chronologies of multiple substances that could serve as dynamic markers of risk.

Socioeconomic Inequalities in Alcohol and Tobacco Consumption: A National Ecological Study in Mexican Adolescents

Alcohol and cigarettes are the psychoactive substances that adolescents use most frequently. When both addictions are combined, they carry the worst burden of disease globally. The objective of this study was to identify whether socioeconomic factors correlate with alcohol and tobacco consumption in Mexican adolescents aged 10 years or more and to establish the relationship in the consumption between the two substances. This ecological study utilized data describing alcohol and tobacco consumption among adolescents aged 10-16 years (n = 48,837 ≈ N = 11,621,100). Having ever consumed any alcohol-containing beverage constituted alcohol consumption. Smoking a cigarette within 30 days constituted cigarette consumption. For both variables, the state-level percentages reported in the survey were used. Diverse socioeconomic variables were collected from official sources. Data on the prevalence of tobacco use and alcohol consumption were entered into an Excel database estimated for each of the states of the Mexican Republic, as well as the socioeconomic variables. We performed the analysis using Stata 14. Consumption prevalence was 15.0% for alcohol and 4.2% for tobacco. Alcohol consumption was not correlated with any studied socioeconomic variable (p > 0.05). The prevalence of tobacco consumption among elementary school students correlated (p < 0.05) with the portion of the population living in private dwellings without sewage, drainage, or sanitation (r = 0.3853). The prevalence of tobacco consumption among middle-school adolescents correlated with the portion of the employed population that earned up to two minimum wages (r = 0.3960), the percentage in poverty by income 2008 (r = 0.4754) and 2010 (r = 0.4531), and the percentage in extreme poverty by income 2008 (r = 0.4612) and 2010 (r = 0.4291). Positive correlations were found between tobacco consumption and alcohol consumption among both elementary (r = 0.5762, p=0.0006) and middle-school children (r = 0.7016, p=0.0000). These results suggest that certain socioeconomic factors correlate with tobacco consumption but not alcohol consumption. A correlation between alcohol consumption and tobacco consumption was observed. The results can be used for developing interventions in adolescents.

Prevalence and factors associated with substance use among HIV positive youth attending HIV care and treatment centers in Dodoma, Tanzania

BACKGROUND

Substance use among people living with HIV is associated with poor health, social, and psychological outcomes. This study assessed the prevalence of substance use and associated factors among youth attending HIV care and treatment centers (CTCs) in Dodoma, Tanzania.

METHODS

This cross-sectional study was carried out in Dodoma, Tanzania, from February to April 2020 among youth aged 15-24 attending HIV CTCs. Data was collected using sociodemographic, WHO ASSIST Version 3.0, BDI II, and SERAD questionnaires. Data analysis was done using Stata 17. Descriptive statistics were used to summarize continuous and categorical variables. Univariable and multivariable logistic regression analyses were conducted to determine factors independently associated with substance use.

RESULTS

The prevalence of substance use was relatively low (6.6%). Older youth (20 to 24 years) were 2% less likely to use substances compared to the younger ones (15 to 19 years) (AOR: 0.07; 95% CI 0.01, 0.83). There were statistically significant decreasing odds of substance use with every year increase in age at HIV diagnosis (OR: 1.66; 95% CI 1.14, 2.41). Being unemployed was statistically significantly associated with decreased odds of substance use among this population (OR: 0.03; 95% CI 0.02, 0.33). Youth who had detectable viral loads were significantly more likely to use substances compared to those with undetectable viral loads (AOR: 12.9; 95% CI 1.07, 156.05).

CONCLUSIONS

Despite the low prevalence of substance use found in this study, it is important to note that late age of HIV diagnosis, employment, and detectable viral load negatively impacted HIV positive youth with regards to substance use. It is recommended that CTCs emphasize routine screening for substance use among youth who have detectable viral loads.

Mediterranean Alcohol-Drinking Patterns and All-Cause Mortality in Women More Than 55 Years Old and Men More Than 50 Years Old in the "Seguimiento Universidad de Navarra" (SUN) Cohort

BACKGROUND

Most of the available epidemiological evidence on alcohol and chronic disease agrees on recommending alcohol abstention to young people, but some controversy exists about the most appropriate recommendation for alcohol abstention for people of older ages. A growing body of evidence suggests that the pattern of alcohol consumption is likely to be a strong effect modifier. The Mediterranean Alcohol Drinking Pattern (MADP) represents a score integrating several dimensions of drinking patterns (moderation, preference for red wine, drinking with meals, and avoiding binge drinking). Our aim was to clarify this issue and provide more precise recommendations on alcohol consumption.

METHODS

We prospectively followed-up 2226 participants (men older than 50 years and women older than 55 years at baseline) in the Seguimiento Universidad de Navarra (SUN) cohort. We classified participants into three categories of adherence to the MADP score (low, moderate, and high), and we added a fourth category for abstainers. Cox regression models estimated multivariable-adjusted hazard ratios (HR) of all-cause death and 95% confidence intervals (CI) using low MADP adherence as the reference category.

RESULTS

The strongest reduction in risk of mortality was observed for those with high adherence to the MADP, with an HR of 0.54 (95% CI: 0.37-0.80). The moderate adherence group (HR = 0.65, 95% CI: 0.44-0.96) and the abstention group (HR = 0.60, 95% CI: 0.36-0.98) also exhibited lower risks of mortality than the low MADP adherence group.

CONCLUSIONS

based on the available evidence, a public health message can be provided to people older than 50 years as follows: among those who drink alcohol, high adherence to the MADP score could substantially reduce their risk of all-cause mortality.

Combined use of alcohol and cannabis: Introduction to the special issue

OBJECTIVE

Combined use of alcohol and cannabis has increased in recent years among certain age groups, and it is well established that individuals who use both alcohol and cannabis (especially if they use both at the same time) are at increased risk for substance-related harms relative to individuals who use only one substance. Far less attention has been placed on the patterns, predictors, and psychological processes associated with alcohol and cannabis co-use, which may inform prevention and intervention programming. Accordingly, this special issue was assembled to advance our understanding of the characteristics and consequences of combined use of alcohol and cannabis.

METHOD

In this introductory article, the Guest Editors present the background for this work and provide an overview of the 14 articles that comprise this special issue.

RESULTS

Studies contained in this special issue capitalize on a variety of methodologies, with a particular focus on investigating typologies of alcohol and cannabis co-use, clarifying motivational and social contexts of co-use, and tracking co-use in daily life via daily diary and ecological momentary assessment designs. Experimental and neuroimaging examinations of co-use are also included. Collectively, the studies generally provide evidence that combined use of alcohol and cannabis is associated with unique characteristics, predictors, consequences, and psychological processes relative to single-substance use.

CONCLUSIONS

The studies in this special issue provide new insight into combined use of alcohol and cannabis. They also highlight a number of promising avenues for future inquiry as the literature on alcohol and cannabis co-use continues to grow. (PsycInfo Database Record (c) 2021 APA, all rights reserved).