Findings

To party, or not to party

Kevin Lewis

December 27, 2018

The Effect of Marijuana Dispensary Openings on Housing Prices
Jesse Burkhardt & Matthew Flyr
Contemporary Economic Policy, forthcoming

Abstract:
We evaluate the effect of medical and recreational dispensary openings on housing prices in Denver, Colorado. Using an event study approach, we find that the introduction of a new dispensary within a half‐mile radius of a new home increases home prices by approximately 7.7% on average. The effect diminishes for homes further from new dispensaries but is consistent over time. Our results provide important and timely empirical evidence on the socioeconomic impacts of marijuana legalization.


Prevalence of Cannabis Use in Youths After Legalization in Washington State
Julia Dilley et al.
JAMA Pediatrics, forthcoming

"The Washington Healthy Youth Survey (HYS) is an anonymous, school-based survey of 8th, 10th, and 12th graders and the state’s primary source of information about health behavior among youths. The HYS has been implemented in the fall of even-numbered years since 2002, using a simple random sample of public schools to generate a state-representative sample...We generated covariate-adjusted prevalence estimates...HYS shows statistically significant declines in prevalence from 2010-2012 to 2014-2016 among both 8th graders (from 9.8% [95% CI, 9.1%-10.5%] to 7.3% [95% CI, 6.6%-8.0%]; P < .001) and 10th graders (from 19.8% [95% CI, 18.6%-21.0%] to 17.8% [95% CI, 16.7%-18.9%]; P = .01)."


Socioeconomic Status and Adolescent Alcohol Involvement: Evidence for a Gene–Environment Interaction
Christal Davis & Wendy Slutske
Journal of Studies on Alcohol and Drugs, September 2018, Pages 725–732

Method: A total of 839 same-sex adolescent twin pairs (509 monozygotic and 330 dizygotic) from the 1962 National Merit Twin Study completed a questionnaire containing items assessing alcohol involvement. Twins were approximately 17 years old at the time of participation. Parents provided reports of family income and educational attainment. Models were fit examining parental education and family income as moderators of genetic and environmental influences on alcohol use.

Results: There was evidence for moderation of genetic and environmental influences on alcohol involvement by family income. For twins with the lowest levels of family income, genetic and shared environmental influences accounted for 50% and 26% of the variance in alcohol involvement, respectively, compared with 2% and 67% of the variance among those at the highest level of income.


Rational Self-Medication
Michael Darden & Nicholas Papageorge
NBER Working Paper, December 2018

Abstract:
We develop a theory of rational self-medication. The idea is that forward-looking individuals, lacking access to better treatment options, attempt to manage the symptoms of mental and physical pain outside of formal medical care. They use substances that relieve symptoms in the short run but that may be harmful in the long run. For example, heavy drinking could alleviate current symptoms of depression but could also exacerbate future depression or lead to alcoholism. Rational self-medication suggests that, when presented with a safer, more effective treatment, individuals will substitute towards it. To investigate, we use forty years of longitudinal data from the Framingham Heart Study and leverage the exogenous introduction of selective serotonin reuptake inhibitors (SSRIs). We demonstrate an economically meaningful reduction in heavy alcohol consumption for men when SSRIs became available. Additionally, we show that addiction to alcohol inhibits substitution. Our results suggest a role for rational self-medication in understanding the origin of substance abuse. Furthermore, our work suggests that punitive policies targeting substance abuse may backfire, leading to substitution towards even more harmful substances to self-medicate. In contrast, policies promoting medical innovation that provide safer treatment options could obviate the need to self-medicate with dangerous or addictive substances.


How and why have attitudes about cannabis legalization changed so much?
Jacob Felson, Amy Adamczyk & Christopher Thomas
Social Science Research, forthcoming

Abstract:
Since the late 1990s public opinion about cannabis legalization has become drastically more liberal, and some states have begun to legalize cannabis for recreational use. Why have attitudes changed so much? Prior research has considered a few of the reasons for this change, but this is the first comprehensive and empirically-based study to consider the wide range of potential causes for how and why this happened. We use data from the General Social Survey, National Study of Drug Use and Health, and word searches from the New York Times. We find that attitudes largely liberalized via intracohort changes. Most Americans developed more liberal views, regardless of their race and ethnicity, gender, education, religious or political affiliation, or religious engagement. Changes in cannabis use have had minimal effects on attitudes, and legalization of cannabis has not prompted attitude change in neighboring states. As to root causes, evidence suggests that a decrease in religious affiliation, a decline in punitiveness, and a shift in media framing all contributed to changing attitudes.


Disentangling longitudinal relations between youth cannabis use, peer cannabis use, and conduct problems: Developmental cascading links to cannabis use disorder
Ivy Defoe et al.
Addiction, forthcoming

Design, Setting, Participants: Longitudinal study analyzing four waves of longitudinal data from 364 racially and socio‐economically diverse, urban, US community youth (at baseline: Mage = 13.51 (0.95); 49.1% female).

Findings: Change in cannabis use did not predict changes in conduct problems or peer cannabis use over time, controlling for gender, race–ethnicity and socio‐economic status. Instead, increases in conduct problems predicted increases in cannabis use and ultimately CUD, with some of the effect mediated by increases in the prevalence of peer cannabis use [β = 0.12, 95% confidence interval (CI) = 0.07, 0.20]. Additionally, affiliation with peers who used cannabis predicted subsequent CUD via increased personal cannabis use (β = 0.08, 95% CI = 0.04, 0.14). Significant within‐person betas for the cross‐lagged effects ranged between 0.20 and 0.27.

Conclusions: Cannabis use in adolescence does not appear to lead to greater conduct problems or association with cannabis‐using peers apart from pre‐existing conduct problems. Instead, adolescents who (1) increasingly affiliate with cannabis‐using peers or (2) have increasing levels of conduct problems are more likely to use cannabis, and this cascading chain of events appears to predict cannabis use disorder in emerging adulthood.


The Effects of Medicare Advantage on Opioid Use
Laurence Baker, Kate Bundorf & Daniel Kessler
NBER Working Paper, December 2018

Abstract:
Despite a vast literature on the determinants of prescription opioid use, the role of health insurance plans has received little attention. We study how the form of Medicare beneficiaries’ drug coverage affects the volume of opioids they consume. We find that enrollment in Medicare Advantage, which integrates drug coverage with other medical benefits, significantly reduces beneficiaries’ likelihood of filling an opioid prescription, as compared to enrollment in a stand-alone drug plan. Approximately half of this effect was due to fewer fills from prescribers who write a very large number of opioid prescriptions.


Reward activation in childhood predicts adolescent substance use initiation in a high-risk sample
Lora Cope et al.
Drug and Alcohol Dependence, January 2019, Pages 318-325

Methods: Participants were 34 children (25 male) at high risk for alcohol and other substance use disorders from a longitudinal functional magnetic resonance imaging study, scanned at a mean age of 10.5 years (SD = 1.2) when participants were substance-naïve. We used a monetary incentive delay task to examine the hemodynamic response of the nucleus accumbens to gain and loss anticipation. Logistic regression was used to test the hypothesis that these brain response patterns would have predictive utility over and above early externalizing behaviors and family history of substance use disorder, two key risk factors for substance use problems, in differentiating those who initiated substance use before age 16 (n = 18) and those who did not (n = 16).

Results: Greater nucleus accumbens activation during monetary gain anticipation in childhood increased the likelihood of initiating substance use during early adolescence (p =  .023). The model that comprised neural data in addition to early externalizing behaviors and family history showed significantly better fit than the model without neural data (χ22 = 7.38, p =  .025).


Getting into the Weeds: Does Legal Marijuana Access Blunt Academic Performance in College?
Adam Wright & John Krieg
Economic Inquiry, forthcoming

Abstract:
This paper examines the effect of legal access to marijuana on student performance stemming from a voter‐approved initiative legalizing marijuana for those 21 and older in the State of Washington. Using panel data from a medium‐sized public university, we use a within‐student and within‐class estimator to show that legalization reduces students' grades, with an effect size about one‐half the impact of gaining legal access to alcohol. Consistent with how marijuana consumption affects cognitive functioning, we find that students' grades fall furthest in courses that require more quantitative skills. These effects are largely driven by men and low performers.


Cannabinoid exposure and altered DNA methylation in rat and human sperm
Susan Murphy et al.
Epigenetics, forthcoming

Abstract:
Little is known about the reproductive effects of paternal cannabis exposure. We evaluated associations between cannabis or tetrahydrocannabinol (THC) exposure and altered DNA methylation in sperm from humans and rats, respectively. DNA methylation, measured by reduced representation bisulfite sequencing, differed in the sperm of human users from non-users by at least 10% at 3,979 CpG sites. Pathway analyses indicated Hippo Signaling and Pathways in Cancer as enriched with altered genes (Bonferroni p < 0.02). These same two pathways were also enriched with genes having altered methylation in sperm from THC-exposed versus vehicle-exposed rats (p < 0.01). Data validity is supported by significant correlations between THC exposure levels in humans and methylation for 177 genes, and substantial overlap in THC target genes in rat sperm (this study) and genes previously reported as having altered methylation in the brain of rat offspring born to parents both exposed to THC during adolescence. In humans, cannabis use was also associated with significantly lower sperm concentration. Findings point to possible pre-conception paternal reproductive risks associated with cannabis use.


Higher average potency across the United States is associated with progression to first cannabis use disorder symptom
Brooke Arterberry et al.
Drug and Alcohol Dependence, forthcoming

Methods: Data sources were the Michigan Longitudinal Study, an ongoing prospective, high-risk family study investigating the course and predictors for substance use disorders among youth beginning prior to school entry and time-parallel national average trends in delta-9-tetrahydrocannabinol (i.e., psychoactive compound in cannabis). The national average trends in delta-9-tetrahydrocannabinol were used to estimate potency level for the individual. Only cannabis users were included in analyses (n = 527).

Results: Cox regression showed an increased risk of progression from cannabis initiation to cannabis use disorder symptom onset by 1.41 times (p < .001) for each unit increase in national average delta-9-tetrahydrocannabinol as compared to those not endorsing CUD symptom onset, adjusting for sex, regular use, and cohort effects. Accounting for regular use, individuals initiating cannabis at national average 4.9% delta-9-tetrahydrocannabinol were at 1.88 times (p = .012) higher risk for cannabis use disorder symptom onset within one year compared to those who did not endorse CUD symptom onset, while those initiating cannabis at national average 12.3% delta-9-tetrahydrocannabinol were at 4.85 times (p = .012) higher risk within one year.


Gender and the Politics of Marijuana
Laurel Elder & Steven Greene
Social Science Quarterly, forthcoming

Objectives: The objectives of this study were to understand why, even though women are more liberal than men on a broad range of issues, when it comes to the increasingly prominent issue of marijuana legalization, the direction of the gender gap is reversed, with women more conservative than men.

Methods: Relying on a 2013 Pew survey — unique for the extensiveness of its marijuana questions, including marijuana usage — we explore and attempt to explain the nature of this unusual gender gap. We test several hypotheses rooted in the different life experiences of women and men.

Results: We find that women's role as mothers cannot explain this gap, and that mothers are in fact no different from those without children in terms of their support for marijuana policy, as well as their reported use of marijuana. The greater religiosity of women does play a prominent role in the gender gap on marijuana policy, but does not account for the full difference of opinion between women and men. Our findings suggest that men's greater propensity relative to women to use marijuana is a major driver behind the gender gap.


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