Everything in moderation

Kevin Lewis

August 02, 2018

Falling rates of marijuana dependence among heavy users
Steven Davenport
Drug and Alcohol Dependence, forthcoming

Introduction: Marijuana use has become increasingly popular in the United States since the turn of the century, and typical use patterns among past-month marijuana users have intensified, raising concerns for an increase in cannabis use disorders (CUDs). Yet the population prevalence of CUDs has mostly remained flat. We analyzed trends in DSM-IV marijuana dependence among Daily/Near-Daily (DND) users, both overall and by age and gender, and considered potential explanations.

Methods: Using data assembled from the National Survey on Drug Use and Health (2002-2016), rates of self-reported dependence and constituent symptoms are calculated for DND marijuana users; logistic regressions with pre- and post- periods (2002-2004, 2014-2016) and a Cochrane-Armitage trend test are applied to describe temporal changes.

Results: Dependence among DND users fell by 39% (26.5%-16.1%; p < 0.001), with significant trend. No significant change is detected at the population level. Sub-group analysis shows a steep gradient for age but not for gender. Declines are robust to sub-group analysis, except for users over 50 years old. Among dependence symptoms, most showed significant declines: reducing important activities (p < 0.001); use despite emotional, mental, or physical problems (p < 0.001); failing attempts to cutback (p < 0.001); lots of time getting, using, or getting over marijuana (p < 0.01); and failing to keep limits set on use (p < .05). Reported tolerance showed no significant change.

Cannabis decriminalization: A study of recent policy change in five U.S. states
Richard Grucza et al.
International Journal of Drug Policy, September 2018, Pages 67-75

Background: A number of public health professional organizations support the decriminalization of cannabis due to adverse effects of cannabis-related arrests and legal consequences, particularly on youth. We sought to examine the associations between cannabis decriminalization and both arrests and youth cannabis use in five states that passed decriminalization measures between the years 2008 and 2014: Massachusetts (decriminalized in 2008), Connecticut (2011), Rhode Island (2013), Vermont (2013), and Maryland (2014).

Methods: Data on cannabis possession arrests were obtained from federal crime statistics; data on cannabis use were obtained from state Youth Risk Behavior Survey (YRBS) surveys, years 2007–2015. Using a “difference in difference” regression framework, we contrasted trends in decriminalization states with those from states that did not adopt major policy changes during the observation period.

Results: Decriminalization was associated with a 75% reduction in the rate of drug-related arrests for youth (95% CI: 44%, 89%) with similar effects observed for adult arrests. Decriminalization was not associated with any increase in the past-30 day prevalence of cannabis use overall (relative change=−0.2%; 95% CI: −4.5%, 4.3%) or in any of the individual decriminalization states.

Marijuana Legalization and Crime Clearance Rates: Testing Proponent Assertions in Colorado and Washington State
David Makin et al.
Police Quarterly, forthcoming


The legalization of recreational cannabis in Washington state (I-502) and Colorado (A-64) created a natural experiment with ancillary unknowns. Of these unknowns, one of the more heavily debated is that of the potential effects on public health and safety. Specific to public safety, advocates of legalization expected improvements in police effectiveness through the reduction in police time and attention to cannabis offenses, thus allowing them to reallocate resources to more serious offenses. Using 2010 to 2015 Uniform Crime Reports data, the research undertakes interrupted time-series analysis on the offenses known to be cleared by arrest to create monthly counts of violent and property crime clearance rate as well as disaggregated counts by crime type. Findings suggest no negative effects of legalization on crime clearance rates. Moreover, evidence suggests some crime clearance rates have improved. Our findings suggest legalization has resulted in improvements in some clearance rates.

Opioids and the Labor Market
Dionissi Aliprantis & Mark Schweitzer
Federal Reserve Working Paper, May 2018


This paper finds evidence that opioid availability decreases labor force participation while a large labor market shock does not influence the share of opioid abusers. We first identify the effect of availability on participation using the geographic variation in opioid prescription rates. We use a combination of the American Community Survey (ACS) and Centers for Disease Control and Prevention (CDC) county-level prescription data to examine labor market patterns across both rural and metropolitan areas of the United States from 2007 to 2016. Individuals in areas with higher prescription rates are less likely to participate after accounting for standard demographic factors and regional controls. This relationship remains significant for important demographic groups when increasingly strong panel data controls, including a full set of geographic fixed effects and measures of local labor market conditions in 2000, are introduced to the regressions. We also investigate the possibility of reverse causality, using the Great Recession as an instrument to identify the effect of weak labor demand on opioid abuse. The share abusing opioids did not increase after the onset of the Great Recession. The evidence on the frequency of abuse is more ambiguous since the identified increases could be the continuation of a pre-trend.

Internet searches for opioids predict future emergency department heroin admissions
Sean Young et al.
Drug and Alcohol Dependence, forthcoming

Methods: Across nine metropolitan statistical areas (MSAs) in the United States, we obtained data on Google searches for prescription and non-prescription opioids, as well as Substance Abuse and Mental Health Services Administration (SAMHSA) data on heroin-related ED visits from 2004-2011. A linear mixed model assessed the relationship between opioid-related Internet searches and following year heroin-related visits, controlling for MSA GINI index and total number of ED visits.

Results: The best-fitting model explained 72% of the variance in heroin-related ED visits. The final model included the search keywords “Avinza,” “Brown Sugar,” “China White,” “Codeine,” “Kadian,” “Methadone,” and “Oxymorphone.” We found regional differences in where and how people searched for opioid-related information.

Trends in Abstaining From Substance Use in Adolescents: 1975–2014
Sharon Levy et al.
Pediatrics, forthcoming

Methods: Data from the nationally representative Monitoring the Future survey, administered 1975–2014, were analyzed to determine the annual proportion of abstinent students. The 2014 Monitoring the Future cohort was analyzed to determine associations between nonuse and risk and protective factors.

Results: The prevalence of abstaining seniors between 1976 and 2014 increased fivefold for lifetime abstinence and more than doubled for past 30 days; similar increases were reported by younger students between 1991 and 2014. Trend lines were distinct for alcohol, which increased steadily over the past 38 years; tobacco, which increased dramatically over the past 20 years; and marijuana and illicit drugs, which increased slightly, although not consistently, between 1976 and 2014. In 2014, students that identified as male, African American, or other race and those who reported greater religious commitment were significantly more likely to report lifetime abstinence. Students that lived in single-parent households, spent more evenings out, worked more hours during the school year, and reported lower grades and more truancy had lower abstinence rates.

Estimating Causal Effects of Alcohol Access and Use on a Broad Set of Risky Behaviors: Regression Discontinuity Evidence
Jason Fletcher
University of Wisconsin Working Paper, June 2018


A growing body of evidence suggests large increases in criminal behavior and mortality coinciding with a young adult's 21st birthday, when alcohol consumption becomes legal. The policy implications from these findings have focused on the need to reduce drinking among young people, potentially by enforcing stricter alcohol controls. However, mortality and arrests are relatively infrequent outcomes and relatively less is known about the intermediate and more prevalent consequences of legal access to alcohol at age 21. This paper uses the Add Health data combined with a regression discontinuity approach to examine the effects of alcohol access on sexual behavior, drunk driving, violence, and other outcomes. The results suggest relatively large effects that appear concentrated in men. The sample also allows some suggestive policy implications on whether changing the minimum drinking age may reduce these consequences.

The Role of Health Insurance on Treatment for Opioid Use Disorders: Evidence from the Affordable Care Act Medicaid Expansion
Angélica Meinhofer & Allison Witman
Journal of Health Economics, July 2018, Pages 177-197


We estimate the effect of health insurance coverage on opioid use disorder treatment utilization and availability by exploiting cross-state variation in effective dates of Medicaid expansions under the Affordable Care Act. Using a difference-in-differences design, we find that aggregate opioid admissions to specialty treatment facilities increased 18% in expansion states, most of which involved outpatient medication-assisted treatment (MAT). Opioid admissions from Medicaid beneficiaries increased 113% without crowding out admissions from individuals with other health insurance. These effects appeared to be driven by market entry of select MAT providers and by greater acceptance of Medicaid payments among existing MAT providers. Moreover, effects were largest in expansion states with comprehensive MAT coverage. Our findings suggest that Medicaid expansions resulted in substantial utilization and availability gains to clinically efficacious and cost-effective pharmacological treatments, implying potential benefits of expanding Medicaid to non-expansion states and extending MAT coverage.

Oregon recreational marijuana legalization: Changes in undergraduates’ marijuana use rates from 2008 to 2016
David Kerr, Harold Bae & Andrew Koval
Psychology of Addictive Behaviors, forthcoming


There have been few studies of marijuana use before and after recreational marijuana legalization (RML) in affected states. We tested whether marijuana use rates increased more among college students in Oregon than in non-RML states following Oregon RML in July 2015. Repeated cross-sectional National College Health Assessment−II surveys were completed by random samples of students within participating colleges from 2008 to 2016. Data were from 4-year institutions that participated both before and after Oregon RML. Undergraduates (ages 18–26 years) from 2 institutions in Oregon (n = 7,412) and 123 institutions (n = 274,340) in non-RML U.S. states self-reported use of marijuana, tobacco, alcohol, and other drugs in the past 30 days. Mixed-effects regressions accounted for clustering of participants within institutions and controlled for individual-, context-, and institution-level factors as well as secular changes in substance use rates from 2008 to 2016. Following RML, Oregon students (compared to non-RML-state students) showed relative increases in rates of marijuana use (odds ratio [OR] = 1.29, 95% confidence interval [CI: 1.13, 1.48], p = .0002, and decreases in tobacco use rates (OR = .71, 95% CI [.60, .85], p < .0001). Changes in marijuana use after RML did not differ significantly for participants under and over age 21 years. Some study limitations would be addressed with higher survey response rates, inclusion of other Oregon institutions, and controls for marijuana and other substance policies. Still, findings are consistent with an effect of RML on rates of marijuana use among young adult college students, which may have important public health implications.

Peer effects on adolescent smoking: Are popular teens more influential?
Juan David Robalino & Michael Macy
PLoS ONE, July 2018


Previous research on adolescent cigarette adoption has focused on peer influence and the perceived status gain from smoking but has ignored the status effects on peer influence. We analyze adolescent peer effects on cigarette consumption while considering the popularity of peers. The analysis is based on a four wave panel survey representative of American high school students. We measure peers’ popularity by their eigenvector centrality in high school social networks. Using lagged peers’ behavior, school fixed effects, and instrumental variables to control for homophily and contextual confounds, we find that the probability of smoking the following year increases with the mean popularity of smokers, while the popularity of non-smokers has the opposite effect. These effects persist seven and fourteen years later (wave 3 and 4 of the data). In addition, the probability of smoking increases with the smoking propensity of the 20% most popular teens and decreases with the smoking propensity of the bottom 80%. The results indicate the importance of knowing not only the smoking propensity within a school but also the location of smokers within the social hierarchy.

Education, Smoking, and Cohort Change: Forwarding a Multidimensional Theory of the Environmental Moderation of Genetic Effects
Robbee Wedow et al.
American Sociological Review, forthcoming


Sociologists interested in the effects of genes on complex social outcomes claim environmental conditions structure when and how genes matter, but they have only studied environmental moderation of genetic effects on single traits at a time (gene-by-environment interactions). In this article, we propose that the social environment can also transform the genetic link between two traits. Taking the relationship between educational attainment and smoking as an exemplary case, we use genome-wide methods to examine whether genetic variants linked to education are also linked to smoking, and whether the strength of this relationship varies across birth cohorts. Results suggest that the genetic relationship between education and smoking is stronger among U.S. adults born between 1974 and 1983 than among those born between 1920 and 1959. These results are supported by replication in additional data from the United Kingdom. Environmental conditions that differ across birth cohorts may result in the bundling of genetic effects on multiple outcomes, as anticipated by classic cohort theory. We introduce genetic correlation-by-environment interaction [(rG)xE] as a sociologically-informed model that will become especially useful as data for more well-powered analyses become available.

Medication for Opioid Use Disorder After Nonfatal Opioid Overdose and Association With Mortality: A Cohort Study
Marc Larochelle et al.
Annals of Internal Medicine, forthcoming

Background: Opioid overdose survivors have an increased risk for death. Whether use of medications for opioid use disorder (MOUD) after overdose is associated with mortality is not known.

Participants: 17,568 Massachusetts adults without cancer who survived an opioid overdose between 2012 and 2014.

Measurements: Three types of MOUD were examined: methadone maintenance treatment (MMT), buprenorphine, and naltrexone. Exposure to MOUD was identified at monthly intervals, and persons were considered exposed through the month after last receipt. A multivariable Cox proportional hazards model was used to examine MOUD as a monthly time-varying exposure variable to predict time to all-cause and opioid-related mortality.

Results: In the 12 months after a nonfatal overdose, 2040 persons (11%) enrolled in MMT for a median of 5 months (interquartile range, 2 to 9 months), 3022 persons (17%) received buprenorphine for a median of 4 months (interquartile range, 2 to 8 months), and 1099 persons (6%) received naltrexone for a median of 1 month (interquartile range, 1 to 2 months). Among the entire cohort, all-cause mortality was 4.7 deaths (95% CI, 4.4 to 5.0 deaths) per 100 person-years and opioid-related mortality was 2.1 deaths (CI, 1.9 to 2.4 deaths) per 100 person-years. Compared with no MOUD, MMT was associated with decreased all-cause mortality (adjusted hazard ratio [AHR], 0.47 [CI, 0.32 to 0.71]) and opioid-related mortality (AHR, 0.41 [CI, 0.24 to 0.70]). Buprenorphine was associated with decreased all-cause mortality (AHR, 0.63 [CI, 0.46 to 0.87]) and opioid-related mortality (AHR, 0.62 [CI, 0.41 to 0.92]). No associations between naltrexone and all-cause mortality (AHR, 1.44 [CI, 0.84 to 2.46]) or opioid-related mortality (AHR, 1.42 [CI, 0.73 to 2.79]) were identified.

Conclusion: A minority of opioid overdose survivors received MOUD. Buprenorphine and MMT were associated with reduced all-cause and opioid-related mortality.

Medical Marijuana Availability, Price, and Product Variety, and Adolescents' Marijuana Use
Yuyan Shi, Sharon Cummins & Shu-Hong Zhu
Journal of Adolescent Health, July 2018, Pages 88-93

Methods: A representative sample of 8th, 10th, and 12th graders (N = 46,646) from 117 randomly selected schools in California participated in the cross-sectional 2015–2016 California Student Tobacco Survey (CSTS). Characteristics of medical marijuana dispensaries in California were collected and combined with school locations to compute availability, price, and product variety of medical marijuana in school neighborhoods. Multilevel logistic regressions with random intercepts at school level were conducted to test the associations, accounting for individual and school socioeconomic characteristics.

Results: The distance from school to the nearest medical marijuana dispensary (within 0- to 1-mi and 1- to 3-mi bands) was not associated with adolescents' use of marijuana in the past month or susceptibility to use marijuana in the future, nor was the weighted count of medical marijuana dispensaries within the 3-mi band of school. Neither the product price nor the product variety in the dispensary nearest to school was associated with marijuana use or susceptibility to use. The results were robust to different specifications of medical marijuana measures.


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