Delineating prototypical patterns of substance use initiations over time

Internalizing and externalizing pathways to high-risk substance use and geographic location in Australian adolescents

One specific instantiation of the storm-and-stress view of adolescence is the idea that “normal” adolescence involves high-risk substance use behaviors. However, although uptake of some substance use behaviors is more common during adolescence than other life stages, it is clear that not all adolescents engage in risky substance use—and among those who do, there is much variation in emotional, behavioral, and contextual precursors of this behavior. One such set of predictors forms the internalizing pathway to substance use disorder, whereby internalizing symptoms in childhood such as negative affect and anxiety set off a chain of consequences culminating in high-risk substance use in late adolescence. However, findings linking internalizing symptoms to substance use are mixed, and it is clear that this link varies across adolescents and contexts. One heretofore unanswered question is whether and how geographic location, specifically whether the adolescent lives in an urban or rural location, moderates this link. The current report is a secondary analysis of data from the Longitudinal Study of Australian Children (LSAC; N = 2,285), in which we examined the link between internalizing symptoms in childhood and initiation of substance use through age 19. Using a multiple event process survival mixture model (MEPSUM), we identified three trajectories of substance use initiation in adolescence: one (65.7% of the sample) characterized by near-complete abstinence until late adolescence, another (27.2%) by earlier initiation of alcohol, nicotine, and cannabis, and another (7.2%) by early initiation of these substances and later initiation of more hazardous drugs such as cocaine and methamphetamine. Although childhood externalizing symptoms increased the risk of being in the second or third class, internalizing symptoms decreased risk when rural and non-rural adolescents were considered together. Few effects of rurality were found, but the negative relationship between internalizing at age 10 and high-risk substance use was only observed among non-rural adolescents. This finding, which was inconsistent with our initial predictions that rurality might confer higher risk for substance use, instead suggests a potentially protective effect of internalizing symptoms for engagement in risky substance use which may differ based on an adolescent’s geographical context.

Effects of Early Social Bonds on Adolescent Trajectories of Sexual Risk Behaviors Among South African Girls

The goal of this manuscript is to advance HIV risk behavior prevention efforts for South African adolescent girls by identifying distinct trajectory patterns across multiple behavioral domains for adolescent and young adults. We draw from a sample of N = 1070 adolescent girls from South Africa who were between the ages of 13-15 at baseline. Participants were followed across 6 waves of data collection between 2011 and 2019. We focus on predicting trajectories between ages 15 and 21. All participants were HIV negative and had not experienced sexual debut at baseline. We examine group-based multi-variable trajectories across several known HIV risk behaviors: earlier age of sexual debut, engaging in unprotected sex, engaging in transactional sex, earlier age at first pregnancy, and exposure to physical IPV. We characterized three prototypical joint trajectories: abstainers (54%), early unprotected sex (36%), and high-risk sexually active (11%). We then predicted membership based on the following baseline risk and protective factors: household expenditures, bonding to school, parental monitoring, number of close friends, and community engagement. We found that school bonding and parental monitoring were the strongest predictor of sexual risk, and that, among those in both the early unprotected sex and high-risk groups, risky behaviors like unprotected and transactional sex most frequently occurred early in adolescence. These findings suggest that interventions should target girls early in adolescence, and that interventions focused at improving school bonding and promoting parental involvement may be most effective at preventing risky sexual behavior.

Cross-substance patterns of alcohol, cigarette, and cannabis use initiation in Black and White adolescent girls

Characterizing variations in the timing of alcohol, cigarette, and cannabis use onset both among and between Black and White youth can inform targeted prevention. The current study aimed to capture cross-substance initiation patterns in Black and White girls and characterize these patterns with respect to substance use related socioeconomic, neighborhood, family, community, and individual level factors. Data were drawn from interviews conducted at ages 8 through 17 in an urban sample of girls (n = 2172; 56.86% Black, 43.14% White). Discrete-time multiple event process survival mixture modeling was used to identify patterns (i.e., classes) representing timing of alcohol, cigarette, and cannabis use initiation, separately by race. Class characteristics were compared using multinomial logistic regression. Among both Black and White girls, four classes, including abstainer and cross-substance early onset classes, emerged. Two classes characterized by mid-adolescence onset (Black girls) and variation in onset by substance (White girls) were also observed. Class differences centered around cannabis for Black girls (e.g., preceding or following cigarette use) and alcohol for White girls (e.g., (in)consistency over time in greater likelihood of initiation relative to cigarette and cannabis use). Several factors distinguishing the classes were common across race (e.g., externalizing behaviors, friends' cannabis use); some were specific to Black girls (e.g., intentions to smoke cigarettes) or White girls (e.g., primary caregiver problem drinking). Findings underscore the need to recognize a more complex picture than a high-risk/low-risk dichotomy for substance use initiation and to attend to nuanced differences in markers of risky onset pathways between Black and White girls.

Trajectories of early alcohol use milestones: Interrelations among initiation and progression

BACKGROUND

Alcohol use shows age-graded patterning, with normative use progressing through characteristic milestones of escalating use or severity. Despite some knowledge about the timing of milestone attainment and sequencing across milestones, there is a gap in our understanding of the earliest stages of use. This study characterizes the timing, sequencing, and speed of progression through milestones beginning with the first sip of alcohol.

METHODS

Sixth through eighth graders (N = 1023; 52% female; 76% White; M = 12.23 years old) completed web surveys through the end of high school. Participants reported on alcohol experiences including the first sip, full drink, consumption of 3+ drinks/occasion (heavy drinking), being drunk, and experiencing acute consequences, from which milestone age and speed of progression (duration) were calculated. Milestone prevalence, sequencing, and timing were characterized, and associations between age of attainment and speed of progression were examined. We also examined whether milestone timing and progression varied by sex and racial/ethnic group.

RESULTS

Overall, milestones followed the expected ordering with the exception of heavy drinking (3+ drinks/occasion) and being drunk, which appear to index similar experiences. An earlier age of attainment was associated with an increased likelihood of attaining each of the milestones. In contrast, once a milestone was achieved, there was reduced risk of initiation of subsequent adjacent milestones for individuals with an earlier first sip and full drink, and earlier initiation was associated with a longer duration to subsequent milestones. Girls were more likely to attain all milestones than boys, but there was no sex difference in the age of attainment. In contrast, Hispanic youth reported earlier ages of initiation than White non-Hispanic youth, but the likelihood of attainment did not vary by race/ethnicity. Rapid progression was observed in females but did not vary by race/ethnicity.

DISCUSSION

Risks associated with early drinking are complex, with little support for normative ordering of milestones beyond the first sip. Although early drinking is associated with an increased risk of subsequent drinking, it does not appear to place the drinker on an accelerated course to heavier use. A nuanced understanding of risks associated with milestone timing may inform intervention efforts.

Developmental patterns of tobacco product and cannabis use initiation in high school

AIMS

To identify prototypical developmental patterns of tobacco product and cannabis use and co-use initiation during adolescence, and determine risk factors for and consequences of these initiation patterns.

DESIGN

Prospective repeated-measures cohort with eight semi-annual assessments during high school. Multiple-event process survival mixture modeling identified latent initiation classes with distinct patterns of variation in timing of use initiation of tobacco products and cannabis. We then estimated: (1) associations of baseline risk factors with membership in initiation classes and (2) differences between initiation classes in frequency of cannabis and tobacco product use at the final assessment.

SETTING

Ten high schools in the Los Angeles, CA, USA metropolitan area, 2013-17.

PARTICIPANTS

Students [1031 (45.4%) males; mean (standard deviation) age at baseline = 14.6 (0.39) years] who had never used any tobacco products or cannabis at baseline 9th grade assessment (n = 2272).

MEASUREMENTS

Self-report measures of electronic cigarette (e-cigarette), combustible cigarette, hookah, cigar/cigarillos and cannabis use were collected at each assessment.

FINDINGS

Four distinct tobacco and cannabis use initiation classes were identified: (1) early and high-risk cannabis and polytobacco initiators (n = 116; 5.1%); (2) early cannabis and polytobacco initiators (n = 172; 7.6%); (3) late cannabis and e-cigarette initiators (n = 431; 19.0%); and (4) abstainers (n = 1553; 68.4%). At baseline, older age for the early and high-risk cannabis and polytobacco initiators [odds ratio (OR) = 1.22, 95% confidence interval (CI) = 1.10, 1.35, P < 0.001], peer cannabis use (OR = 1.60, 95% CI = 1.23, 2.08, P < 0.001) and delinquent behavior (OR = 1.30, 95% CI = 1.08, 1.55, P = 0.004) were associated with membership in the three initiation classes (versus abstainers). Membership in the early and high-risk cannabis and polytobacco initiators class (versus three other classes) was significantly associated with increased past 30-day frequency and daily intensity of use at the final assessment (P-values < 0.001).

CONCLUSIONS

Older age, peer cannabis use and delinquent behavior appear to be risk factors for the initiation of tobacco/cannabis product use among high school students in the Los Angeles metropolitan region. Early and higher-risk polyproduct use initiation appears to be associated with greater escalation of past 30-day and daily tobacco and cannabis use at the end of the high school.

Developmental considerations in survival models as applied to substance use research

Survival analysis is a class of models that are ideal for evaluating questions of timing of events, which makes them well-suited for modeling the development of a process such as initiation of substance use, development of addiction, or post-treatment recovery. The focus of this review paper is to demonstrate how survival models operate in a broader developmental framework and to offer guidance on selecting the appropriate model on the basis of the research question at hand. We provide a basic overview of survival models and then identify several key issues, explain how they pertain to research in the addiction field, and describe studies that utilize survival models to address questions about timing. We discuss the importance of carefully selecting the metric and origin of the time scale that corresponds to developmental process under investigation and we describe types of censoring/truncation. We describe the value of modeling covariates as time-invariant versus time-varying, and make the distinction between time-varying covariates and time-varying effects of covariates. We also explain how to test for substantive differences due to the timing of the assessment of the predictor. We finish the paper with a presentation of relatively novel extensions of survival models, including models that integrate standard statistical mediational analysis with discrete-time survival analysis, models that simultaneously consider order and timing of multiple events, and models that involve joint modeling of longitudinal and survival data. We also present our own substantive examples of various models in an Appendix containing annotated syntax and output.

Beneficial effects of motivational interviewing case management: A latent class analysis of recovery capital among sober living residents with criminal justice involvement

BACKGROUND

This secondary analysis uses data from a recent clinical trial conducted with probationers and parolees with substance use disorders (N = 330) residing in Sober Living Houses (SLHs). The treatment condition received Motivational Interviewing Case Management (MICM), while controls received usual care SLH residency. Both conditions improved on multiple domains, though residents randomized to MICM improved significantly more than usual care controls on criminal justice outcomes. Because MICM is designed to help ex-offenders attain more recovery capital (RC) in multiple domains, we hypothesized MICM participants that already possessed higher RC would show significantly greater improvement at follow-up than usual SLH residents with higher RC. Moreover, MICM and usual SLH residents with low RC would show no differences at 1-year follow-up.

METHODS

A latent class analysis (LCA) grouped participants into two patterns of RC: those with low RC and those with high RC. These classes were interacted with study condition to predict change on six Addiction Severity Indices (ASI) at follow-up.

RESULTS

MICM was more effective for the higher RC class, with greater improvement in drug, legal, and psychiatric outcomes for those who attended at least three MICM sessions. MICM was no more beneficial than usual care for those in a low RC class.

CONCLUSIONS

SLH operators should consider implementation of MICM for residents with more RC resources. Those with fewer recovery resources, such as a history of psychiatric problems or physical/sexual abuse, would benefit from a more intensive intervention to assist them with improving the amount and quality of their RC.

"R U Mad?": Computerized text analysis of affect in social media relates to stress and substance use among ethnic minority emerging adult males

OBJECTIVE

This study examined the interactive role of affectivity and stress in substance use severity among ethnic minority, emerging adult males, using linguistic indicators of affect obtained through social media.

METHOD

Participants were 119 emerging adult, ethnic minority males (ages 18-25) who provided access to their mobile phone text messaging and Facebook activity for 6-months. Computerized text analysis (LIWC2015) was used to obtain linguistic indices of positive and negative affect from texts and Facebook posts. The Perceived Stress Scale was used to measure stress, and items from the Drug Abuse Screening Test were used to measure substance use severity.

RESULTS

Generalized estimating equations showed that higher negative affect in texts was associated with greater substance use severity. Stress moderated the relationship between positive affect expressed in Facebook posts and substance use such that higher positive affect in Facebook posts was associated with less substance use at higher stress and greater substance use at lower stress.

CONCLUSIONS

Findings highlight the complexities of interactions between stress and affectivity. Findings could inform development of substance use interventions for young males that employ social technologies.

Nonmedical prescription opioids and pathways of drug involvement in the US: Generational differences

BACKGROUND

This study sought to specify (1) the position of nonmedical prescription opioids (NMPO) in drug initiation sequences among Millennials (1979-96), Generation X (1964-79), and Baby Boomers (1949-64) and (2) gender and racial/ethnic differences in sequences among Millennials.

METHODS

Data are from the 2013-2014 National Surveys on Drug Use and Health (n = 73,026). We identified statistically significant drug initiation sequences involving alcohol/cigarettes, marijuana, NMPO, cocaine, and heroin using a novel method distinguishing significant sequences from patterns expected only due to correlations induced by common liability among drugs.

RESULTS

Alcohol/cigarettes followed by marijuana was the most common sequence. NMPO or cocaine use after marijuana, and heroin use after NMPO or cocaine, differed by generation. Among successively younger generations, NMPO after marijuana and heroin after NMPO increased. Millennials were more likely to initiate NMPO than cocaine after marijuana; Generation X and Baby Boomers were less likely (odds ratios = 1.4;0.3;0.2). Millennials were more likely than Generation X and Baby Boomers to use heroin after NMPO (hazards ratios = 7.1;3.4;2.5). In each generation, heroin users were far more likely to start heroin after both NMPO and cocaine than either alone. Sequences were similar by gender. Fewer paths were significant among African-Americans.

CONCLUSIONS

NMPOs play a more prominent role in drug initiation sequences among Millennials than prior generations. Among Millennials, NMPO use is more likely than cocaine to follow marijuana use. In all generations, transition to heroin from NMPO significantly occurs only when both NMPO and cocaine have been used. Delineation of drug sequences suggests optimal points in development for prevention and treatment efforts.

Rat animal models for screening medications to treat alcohol use disorders

The purpose of this review is to present animal research models that can be used to screen and/or repurpose medications for the treatment of alcohol abuse and dependence. The focus will be on rats and in particular selectively bred rats. Brief introductions discuss various aspects of the clinical picture, which provide characteristics of individuals with alcohol use disorders (AUDs) to model in animals. Following this, multiple selectively bred rat lines will be described and evaluated in the context of animal models used to screen medications to treat AUDs. Next, common behavioral tests for drug efficacy will be discussed particularly as they relate to stages in the addiction cycle. Tables highlighting studies that have tested the effects of compounds using the respective techniques are included. Wherever possible the Tables are organized chronologically in ascending order to describe changes in the focus of research on AUDs over time. In general, high ethanol-consuming selectively bred rats have been used to test a wide range of compounds. Older studies usually followed neurobiological findings in the selected lines that supported an association with a propensity for high ethanol intake. Most of these tests evaluated the compound's effects on the maintenance of ethanol drinking. Very few compounds have been tested during ethanol-seeking and/or relapse and fewer still have assessed their effects during the acquisition of AUDs. Overall, while a substantial number of neurotransmitter and neuromodulatory system targets have been assessed; the roles of sex- and age-of-animal, as well as the acquisition of AUDs, ethanol-seeking and relapse continue to be factors and behaviors needing further study. This article is part of the Special Issue entitled "Alcoholism".

What's New in Addiction Prevention in Young People: A Literature Review of the Last Years of Research

Rationale: Addiction prevention is a major public health problem, particularly concerning young people. Despite the consensus that primary prevention is essential, the evaluation of its impact is questioned.

Objective: The objective of this paper is to assess the latest knowledge of addiction prevention programs for young people.

Method: Review a collection of research articles using a keyword-based search on three databases: Pubmed, Eric, and PsycInfo. The research was carried out using three groups of keywords and the eligibility study was completed using two criteria: articles published between 2010 and 2017, and articles in refereed journals.

Results: Of a total of 13,720 articles in the three databases, 32 studies were included in the review and listed in a grid with five themes: authors, type of population, total population, addictive behavior, and results. Four categories were created based on the objective of the studies: the evaluation of prevention strategies, the study of risk factors for consumption, the prevalence study and other subjects studied. The analysis of the corpus was used to establish a list of risk factors to be taken into consideration in future interventions and research. A list of key elements for performing effective interventions and future research is also proposed.

Conclusion: The understanding of the prevention strategies implementation process is discussed as a central element for future research, which will combine stakeholders and researchers. The complexity of the situations and the multifactorial aspects of addiction prevention in young people require a multidisciplinary approach involving the various stakeholders and researchers.

A Note on the Use of Mixture Models for Individual Prediction

Mixture models capture heterogeneity in data by decomposing the population into latent subgroups, each of which is governed by its own subgroup-specific set of parameters. Despite the flexibility and widespread use of these models, most applications have focused solely on making inferences for whole or sub-populations, rather than individual cases. The current article presents a general framework for computing marginal and conditional predicted values for individuals using mixture model results. These predicted values can be used to characterize covariate effects, examine the fit of the model for specific individuals, or forecast future observations from previous ones. Two empirical examples are provided to demonstrate the usefulness of individual predicted values in applications of mixture models. The first example examines the relative timing of initiation of substance use using a multiple event process survival mixture model whereas the second example evaluates changes in depressive symptoms over adolescence using a growth mixture model.

Investigating Progression in Substance Use Initiation Using a Discrete-Time Multiple Event Process Survival Mixture (MEPSUM) Approach

The order and timing of substance initiation has significant implications for later problematic patterns of use. Despite the need to study initiation from a multivariate framework, survival analytic methods typically cannot accommodate more than two substances in one model. The Discrete-Time Multiple Event Process Survival Mixture (MEPSUM; Dean, Bauer, & Shanahan, 2014) model represents an advance by incorporating more than two outcomes and enabling establishment of latent classes within a multivariate hazard distribution. Employing a MEPSUM approach, we evaluated patterns of tobacco, alcohol, and cannabis initiation in the National Longitudinal Study of Adolescent to Adult Health (N=18,923). We found four classes that differed in their ages and ordering of peak initiation risk. Demographics, externalizing psychopathology, and personality significantly predicted class membership. Sex differences in the association between delinquency and initiation patterns also emerged. Findings support the utility of the MEPSUM approach in elucidating developmental pathways underlying clinically relevant phenomena.