Kevin Lewis

March 17, 2014

Is Employment Discrimination Based on Tobacco Use Efficient?

Ian Irvine & Hai Nguyen
Contemporary Economic Policy, forthcoming

Numerous employers in over 20 U.S. states currently discriminate legally against smokers in their hiring policies. We analyze the cost of being a smoker, measured in annual hospital days, and compare this with the cost of being a former smoker, the cost of being obese, and the cost of a variety of other medical conditions, relative to the cost of being a never smoker, using three large recent surveys each having in excess of one hundred thousand observations. The paper also explores the cost of former smokers as determined by the number of years since quitting. Smokers as a whole are not found to be the most costly employees. Furthermore, health costs vary dramatically among smokers of different duration and intensity. As a consequence, our results question the efficiency of such discrimination.


The Behavioral Economics of Drunk Driving

Frank Sloan, Lindsey Eldred & Yanzhi Xu
Journal of Health Economics, May 2014, Pages 64–81

This study investigates whether drinker-drivers attributes are associated with imperfect rationality or irrationality. Using data from eight U.S. cities, we determine whether drinker-drivers differ from other drinkers in cognitive ability, ignorance of driving while intoxicated (DWI) laws, have higher rates of time preference, are time inconsistent, and lack self-control on other measures. We find that drinker-drivers are relatively knowledgeable about DWI laws and do not differ on two of three study measures of cognitive ability from other drinkers. Drinker-drivers are less prone to plan events involving drinking, e.g., selecting a designated driver in advance of drinking, and are more impulsive. Furthermore, we find evidence in support of hyperbolic discounting. In particular, relative to non-drinker-drivers, the difference between short- and long-term discount rates is much higher for drinker-drivers than for other drinkers. Implications of our findings for public policy, including incapacitation, treatment, and educational interventions, are discussed.


Cannabis Use and Neurocognitive Functioning in a Non-Clinical Sample of Users

April Thames, Natalie Arbid & Philip Sayegh
Addictive Behaviors, forthcoming

Objective: With the recent debates over marijuana legalization and increases in use, it is critical to examine its role in cognition. While many studies generally support the adverse acute effects of cannabis on neurocognition, the non-acute effects remain less clear. The current study used a cross-sectional design to examine relationships between recent and past cannabis use on neurocognitive functioning in a non-clinical adult sample.

Method: One hundred and fifty-eight participants were recruited through fliers distributed around local college campuses and the community. All participants completed the Brief Drug Use History Form, the Structured Clinical Interview for DSM-IV Disorders, underwent urine toxicology screening, and neurocognitive assessment. Participants consisted of recent users (n = 68), past users (n = 41), and non-users (n = 49).

Results: Recent users demonstrated significantly (p < .05) worse performance than non-users across cognitive domains of attention/working memory (M = 42.4, SD = 16.1 vs. M = 50.5, SD = 10.2), information processing speed (M = 44.3, SD = 7.3 vs. M = 52.1, SD = 11.0), and executive functioning (M = 43.6, SD = 13.4 vs. M = 48.6, SD = 7.2). There were no statistically significant differences between recent users and past users on neurocognitive performance. Frequency of cannabis use in the last 4 weeks was negatively associated with global neurocognitive performance and all individual cognitive domains. Similarly, amount of daily cannabis use was negatively associated with global neurocognitive performance and individual cognitive domains.

Conclusions: Our results support the widespread adverse effects of cannabis use on neurocognitive functioning. Although some of these adverse effects appear to attenuate with abstinence, past users’ neurocognitive functioning was consistently lower than non-users.


Explaining Racial/Ethnic Differences in Adolescent Substance Abuse Treatment Completion in the United States: A Decomposition Analysis

Brendan Saloner, Nicholas Carson & Benjamin Lê Cook
Journal of Adolescent Health, forthcoming

Purpose: To identify contributors to racial/ethnic differences in completion of alcohol and marijuana treatment among adolescents at publicly funded providers.

Methods: The 2007 Treatment Episode Data Set provided substance use history, treatment setting, and treatment outcomes for youth aged 12–17 years from five racial/ethnic groups (N = 67,060). Individual-level records were linked to variables measuring the social context and service system characteristics of the metropolitan area. We implemented nonlinear regression decomposition to identify variables that explained minority-white differences.

Results: Black and Hispanic youth were significantly less likely than whites to complete treatment for both alcohol and marijuana. Completion rates were similar for whites, Native Americans, and Asian-Americans, however. Differences in predictor variables explained 12.7% of the black-white alcohol treatment gap and 7.6% of the marijuana treatment gap. In contrast, predictors explained 57.4% of the Hispanic-white alcohol treatment gap and 19.8% of the marijuana treatment gap. While differences in the distribution of individual-level variables explained little of the completion gaps, metropolitan-level variables substantially contributed to Hispanic-white gaps. For example, racial/ethnic composition of the metropolitan area explained 41.0% of the Hispanic-white alcohol completion gap and 23.2% of the marijuana completion gap. Regional differences in addiction treatment financing (particularly use of Medicaid funding) explained 13.7% of the Hispanic-white alcohol completion gap and 9.8% of the Hispanic-white marijuana treatment completion gap.

Conclusions: Factors related to social context are likely to be important contributors to white-minority differences in addiction treatment completion, particularly for Hispanic youth. Increased Medicaid funding, coupled with culturally tailored services, could be particularly beneficial.


Changes in Alcohol Use after Traumatic Experiences: The Impact of Combat on Army National Guardsmen

Dale Russell et al.
Drug and Alcohol Dependence, forthcoming

Objective: This research documents the impact of combat experiences on alcohol use and misuse among National Guard soldiers. Whereas much research regarding combat personnel is based on post-experience data, this study's design uses both pre- and post-deployment data to identify the association between different types of combat experiences and changes in substance use and misuse.

Method: A National Guard Infantry Brigade Combat Team was surveyed before and after its deployment to Iraq in 2005-2006. Members of the unit completed anonymous surveys regarding behavioral health and alcohol use and, in the post-survey, the combat experiences they had during deployment. The unit was surveyed three months prior to its deployment and three months after its deployment.

Results: Prevalence rates of alcohol use increased from 70.8% pre-deployment to 80.5% post-deployment. Prevalence rates of alcohol misuse more than doubled, increasing from 8.51% before deployment to 19.15% after deployment. However, among the combat experiences examined in this study, changes in alcohol misuse post-deployment appear to be solely affected by the combat experience of killing. Alcohol misuse decreased amongst those who experienced killing during combat.


Effects of Patient Medication Requests on Physician Prescribing Behavior: Results of A Factorial Experiment

John McKinlay et al.
Medical Care, April 2014, Pages 294-299

Objectives: To estimate the effect of patient requests for medications on physician-prescribing behavior, unconfounded by patient, physician, and practice-setting factors.

Research Design: Two experiments were conducted among 192 primary care physicians, each using different video-based scenarios: an undiagnosed “patient” with symptoms strongly suggesting sciatica, and a “patient” with already diagnosed chronic knee osteoarthritis. Half of patients with sciatica symptoms requested oxycodone, whereas the other half requested something to help with pain. Similarly, half of knee osteoarthritis patients specifically requested celebrex and half requested something to help with pain.

Results: 19.8% of sciatica patients requesting oxycodone would receive a prescription for oxycodone, compared with 1% of those making no specific request (P=0.001). Fifty-three percent of knee osteoarthritis patients requesting celebrex would receive it, compared with 24% of patients making no request (P=0.001). Patients requesting oxycodone were more likely to receive a strong narcotic (P=0.001) and less likely to receive a weak narcotic (P=0.01). Patients requesting celebrex were much less likely to receive a nonselective nonsteroidal anti-inflammatory drugs (P=0.008). No patient attributes, physician, or organizational factors influenced a physician’s willingness to accede to a patient’s medication request.

Conclusions: In both scenarios, activated patient requests for a medication substantially affected physician-prescribing decisions, despite the drawbacks of the requested medications.


Policing Cannabis and Drug Related Hospital Admissions: Evidence from Administrative Records

Elaine Kelly & Imran Rasul
Journal of Public Economics, April 2014, Pages 89–114

We evaluate the impact of a policing experiment that depenalized the possession of small quantities of cannabis in the London borough of Lambeth, on hospital admissions related to illicit drug use. To do so, we exploit administrative records on individual hospital admissions classified by ICD-10 diagnosis codes. These records allow the construction of a quarterly panel data set for London boroughs running from 1997 to 2009 to estimate the short and long run impacts of the depenalization policy unilaterally introduced in Lambeth between 2001 and 2002. We find the depenalization of cannabis had significant longer term impacts on hospital admissions related to the use of hard drugs, raising hospital admission rates for men by between 40 and 100% of their pre-policy baseline levels. The impacts are concentrated among men in younger age cohorts. The dynamic impacts across cohorts vary in profile with some cohorts experiencing hospitalization rates remaining above pre-intervention levels three to four years after the depenalization policy is introduced. We combine these estimated impacts on hospitalization rates with estimates on how the policy impacted the severity of hospital admissions to provide a lower bound estimate of the public health cost of the depenalization policy.


Not All Smokers Die Young: A Model for Hidden Heterogeneity within the Human Population

Morgan Levine & Eileen Crimmins
PLoS ONE, February 2014

The ability of some individuals to reach extreme old age in the presence of clearly high exposure to damaging factors may signal an innate biological advantage. For this study we used data on 4,655 current and never smokers, ages 50 and above, from NHANES III to examine whether long-lived smokers represent a biologically resilient phenotype that could facilitate our understanding of heterogeneity in the aging process. Using a proportional hazards model, our results showed that while smoking significantly increased mortality in most age groups, it did not increase the mortality risk for those who were age 80 and over at baseline. Additionally when comparing the adjusted means of biomarkers between never and current smokers, we found that long-lived smokers (80+) had similar inflammation, HDL, and lung function levels to never smokers. Given that factors which allow some individuals to withstand smoking may also enable others to cope with everyday biological stressors, the investigation of long-lived smokers may eventually allow us to identify molecular and genetic mechanisms which enable longevity extension.


Should anyone be riding to glory on the now-descending limb of the crack-cocaine epidemic curve in the United States?

Maria Parker & James Anthony
Drug and Alcohol Dependence, forthcoming

Background: Many pre-clinical and clinical researchers do not appreciate the recent decline in United States (US) population-level incidence of crack-cocaine smoking. At present, no more than about 200 young people start using crack-cocaine each day. Ten years ago, the corresponding estimated daily rate was 1,000. This short communication looks into these trends, surrounding evidence on this important public health topic, and checks whether duration-reducing treatment interventions might be responsible, versus selected alternatives.

Methods: Via analyses of standardized computer-assisted self-interview data from the US National Surveys on Drug Use and Health (NSDUH, 2002-2011; n > 500,000), we evaluated change in incidence estimates, perceived difficulty to acquire crack, risk of using cocaine, treatment entries, and persistence once crack use has started.

Results: We draw attention to a marked overall decline in year-specific incidence rates for crack-cocaine smoking from 2002-2011, especially 2007-2011. There is some variation in estimates of difficulty to acquire crack (p < 0.001) and observed risk of using cocaine among ‘at risk’ susceptibles (p < 0.001), but no appreciable shifts in duration of crack smoking among active users (p > 0.05) nor in proportion of crack users receiving treatment (p > 0.05).

Conclusions: Changing epidemiology of crack-cocaine smoking may rest largely on reductions in newly incident use with no major direct effects due to US cocaine treatment, incarceration, or interdiction. Concurrently, we see quite modest declines in survey-based estimates of cocaine-attributed perceived risk and cocaine availability. As such, we posit that no specific US agency should claim it is ‘riding to glory’ on the descending limb of this epidemic curve.


Trends in Medical Use, Diversion, and Nonmedical Use of Prescription Medications among College Students from 2003 to 2013: Connecting the Dots

Sean Esteban McCabe et al.
Addictive Behaviors, forthcoming

Objectives: To examine trends in the lifetime and past-year prevalence of medical use, diversion, and nonmedical use of four prescription medication classes (i.e., sedative/anxiety, opioid, sleeping, and stimulant) among college students between 2003 and 2013; and to identify demographic and background characteristics associated with trends in past-year nonmedical use of prescription medications.

Methods: A self-administered, cross-sectional Web survey was conducted in 2003, 2005, 2007, 2009, 2011, and 2013 at a large public four-year university in the Midwest United States.

Results: Approximately one in every five individuals reported nonmedical use of at least one prescription medication class in their lifetime. The past-year prevalence of medical use, diversion and nonmedical use of prescription stimulants increased significantly between 2003 and 2013 while the past-year prevalence of medical use, diversion and nonmedical use of prescription opioids decreased significantly over this same time period. The odds of past-year nonmedical use of each prescription medication class were generally greater among males, Whites, members of social fraternities and sororities, and those with a lifetime history of medical use of prescription medications or a past-year history of being approached to divert their prescription medications.

Conclusions: The present study represents the first investigation to demonstrate that trends in medical use of controlled medications parallel changes in diversion and nonmedical use of the same medication class among college students. The findings reinforce the importance of continued monitoring of prescription medication use at colleges to help guide prevention and intervention efforts.


Correlates of Intentions to Use Cannabis among US High School Seniors in the Case of Cannabis Legalization

Joseph Palamar, Danielle Ompad & Eva Petkova
International Journal of Drug Policy, forthcoming

Background: Support for cannabis (“marijuana”) legalization is increasing in the United States (US). Use was recently legalized in two states and in Uruguay, and other states and countries are expected to follow suit. This study examined intentions to use among US high school seniors if cannabis were to become legally available.

Methods: Data from the last five cohorts (2007-2011) of high school seniors in Monitoring the Future, an annual nationally representative survey of students in the US were utilized. Data were analyzed separately for the 6,116 seniors who reported no lifetime use of cannabis and the 3,828 seniors who reported lifetime use (weighted Ns). We examined whether demographic characteristics, substance use and perceived friend disapproval towards cannabis use were associated with 1) intention to try cannabis among non-lifetime users, and 2) intention to use cannabis as often or more often among lifetime users, if cannabis was legal to use.

Results: Ten percent of non-cannabis-using students reported intent to initiate use if legal and this would constitute a 5.6% absolute increase in lifetime prevalence of cannabis use in this age group from 45.6% (95% CI = 46.6, 44.6) to 51.2% (95% CI = 50.2, 52.2). Eighteen percent of lifetime users reported intent to use cannabis more often if it was legal. Odds for intention to use outcomes increased among groups already at high risk for use (e.g., males, whites, cigarette smokers) and odds were reduced when friends disapproved of use. However, large proportions of subgroups of students normally at low risk for use (e.g., non-cigarette-smokers, religious students, those with friends who disapprove of use) reported intention to use if legal. Recent use was also a risk factor for reporting intention to use as often or more often.


Impacts of drinking-age laws on mortality in Canada, 1980-2009

Russell Callaghan et al.
Drug and Alcohol Dependence, forthcoming

Background: Given the recent international debates about the effectiveness and appropriate age setpoints for legislated minimum legal drinking ages (MLDAs), the current study estimates the impact of Canadian MLDAs on mortality among young adults. Currently, the MLDA is 18 years of age in Alberta, Manitoba and Québec, and 19 years in the rest of Canada.

Methods: Using a regression-discontinuity approach, we estimated the impacts of the MLDAs on mortality from 1980-2009 among 16-22-year-olds in Canada.

Results: In provinces with an MLDA of 18 years of age, young men slightly older than the MLDA had significant and abrupt increases in all-cause mortality (14.2%, p = 0.002), primarily due to deaths from a broad class of injuries (16.2%, p = 0.008), including fatalities due to motor vehicle accidents (MVAs) (12.7%, p = 0.038). In provinces/territories with an MLDA of 19 years of age, significant jumps appeared immediately after the MLDA among males in all-cause mortality (7.2%, p = 0.003), including injuries from external causes (10.4%, p < 0.001) and MVAs (15.3%, p < 0.001). Among females, there were some increases in mortality following the MLDA, but these jumps were statistically non-significant.

Conclusions: Canadian drinking-age legislation has a powerful impact on youth mortality. Given that removal of MLDA restrictions was associated with sharp upturns in fatalities among young men, the MLDA likely reduces population-level mortality among male youth under the constraints of drinking-age legislation. Alcohol-control policies should target the transition across the MLDA as a pronounced period of mortality risk, especially among males.


The Myth of Conformity: Adolescents and Abstention from Unhealthy Drinking Behaviors

Carter Rees & Danielle Wallace
Social Science & Medicine, May 2014, Pages 34–45

Adolescent peer groups with pro-drinking group norms are a well-established source of influence for alcohol initiation and use. However, classic experimental studies of social influence, namely ‘minority influence’, clearly indicate social situations in which an individual can resist conforming to the group norm. Using the National Longitudinal Study of Adolescent Health (“Add Health”), a nationally representative sample of adolescents, we find evidence that being a non-drinking adolescent does not unilaterally put youth at risk for drinking onset when faced with a friendship network where the majority of friends drink. Our results also show that a non-drinking adolescent with a majority of drinking friends is significantly less likely to initiate alcohol abuse if he or she has a minority of non-drinking friend(s). Furthermore, a drinking adolescent with a majority of friends who drink has a decreased probability of continuing to drink and has overall lower levels of consumption if he or she has a minority of friends who do not drink. Our findings recognize that adolescent in-group friendships are a mix of behavioral profiles and can perhaps help adolescents continue or begin to abstain alcohol use even when in a friendship group supportive of alcohol use.


Alcohol Use, Drinking Consequences, and Sensitivity to Social Cues among College Women

Peter Vik et al.
Addictive Behaviors, forthcoming

College students who drink vary in the extent to which they experience drinking consequences, prompting a need to identify factors that differentiate higher-risk drinkers from others. The present study investigated whether difficulty processing subtle social information is related to negative drinking consequences experienced within the past year. Specifically, poor ability to detect subtle non-verbal sarcasm cues was predicted to contribute to drinking consequences. Participants were 39 women, aged 18 to 27 (M = 22), who were enrolled in a public, four-year University. Participants completed a video measure of ability to detect sarcastic comments. After controlling for (high school drinking consequences, maximum drinks in the past 3 months, age), poorer performance in the Simple Sarcasm condition (which provided no cues to others’ intentions) explained an additional 10.8% of the variance in recent drinking consequences (ΔF (1, 34) = 6.15, p = .018). When predicting risky/hazardous alcohol use consequences (e.g., driving intoxicated, fights, unplanned/unprotected sex), Simple Sarcasm again improved prediction by explaining an additional 8.6% of the variance (ΔF (1, 34) = 4.75, p = .036). Sarcasm conditions that provided additional cues to others’ meanings were unrelated to alcohol consequences. Findings are discussed within the context of neurological (orbito-frontal – subcortial) pathways that are common to social information and alcohol reinforcement processes.


Racial segregation and maternal smoking during pregnancy: A multilevel analysis using the racial segregation interaction index

Tse-Chuan Yang et al.
Social Science & Medicine, April 2014, Pages 26–36

Drawing from both the place stratification and ethnic enclave perspectives, we use multilevel modeling to investigate the relationships between women’s race/ethnicity (i.e., non-Hispanic white, non-Hispanic black, Asian, and Hispanic) and maternal smoking during pregnancy; and examine if these relationships are moderated by racial segregation in the continental United States. The results show that increased interaction with whites is associated with increased probability of maternal smoking during pregnancy for Asian and Hispanic mothers. In addition, racial segregation moderates the relationships between race/ethnicity and maternal smoking. Specifically, living in a less racially segregated area is related to a lower probability of smoking during pregnancy for black women, but it could double and almost triple the probability of smoking for Asian women and Hispanic women, respectively. Our findings provide empirical evidence for both the place stratification and ethnic enclave perspectives.


Changes in cigarette and alcohol use during cannabis abstinence

David Allsop et al.
Drug and Alcohol Dependence, forthcoming

Objective: Cannabis causes lower mortality and morbidity than alcohol and tobacco so it is clinically important if quitting cannabis is associated with substitution with these substances. This study tests if cannabis is substituted with alcohol and/or tobacco during cannabis abstinence, and factors predicting such substitution.

Method: A secondary analysis of a prospective community based study quantified cannabis, alcohol and tobacco use with Timeline Follow-back during a two-week voluntary cannabis abstinence and at one-month follow-up in non-treatment seeking cannabis users (n = 45). Cannabis use was verified by urine THC-COOH levels.

Results: Alcohol use increased by 8 standard units (SU; d = 0.48)/week and cigarette use by 14 cigarettes/week (d = 0.29) during cannabis abstinence. Those using less of each substance at baseline had greater increases during cannabis abstinence (alcohol P < 0.0001, tobacco P = 0.01). There was a decrease in alcohol (-4.8 SU, d = -0.29) and tobacco (-13 cigarettes/week, d = -0.26) use at follow-up, when most participants (87%, n = 39) had resumed cannabis use. Increased cigarette use was predicted by cannabis withdrawal related sleep difficulty (insomnia) (P = 0.05), restlessness (P = 0.03) and physical symptoms (P = 0.02). Neither alcohol nor cigarette use increased significantly in those (13.3%, n = 6) who remained abstinent from cannabis through to follow-up.

Conclusions: Abstaining from cannabis was associated with increases in alcohol and tobacco use that decreased with resumption of cannabis use; however there were no increases in individuals who remained abstinent from cannabis at one-month follow-up. Tobacco use did not increase in those experiencing milder cannabis withdrawal symptoms. Research on substitution in treatment seekers during outpatient cannabis abstinence is needed.


‘Me and My Drank:’ Exploring the Relationship Between Musical Preferences and Purple Drank Experimentation

Melanie Hart et al.
American Journal of Criminal Justice, March 2014, Pages 172-186

“Purple drank” is a label typically applied to mixtures of codeine cough syrup with soda, although it has also been applied to mixtures of over-the-counter cough syrups and alcohol. This novel drug formulation was first popularized in the Houston, Texas rap music scene in the 1990’s, and since then references to purple drank have become common in rap and hip-hop songs, but remained virtually absent in other musical genres. Prior research has found that musical preferences can have an influence on choice and frequency of drug use. The goal of the present study is to examine the relationship between musical preferences and experimentation with purple drank. Self-reported information about musical preferences, substance use, and demographic characteristics were collected from 2,349 students at a large university in the southeastern United States. An analysis of lifetime purple drank and other drug use by musical preferences reveals that those who prefer rap/hip-hop music and rock/alternative have the highest risk for reporting purple drank use. Further, this relationship far exceeds the associations between musical preferences and other drugs. Results from logistic regression analyses indicate males, other drug users, and those that prefer rap/hip-hop music have a significantly higher likelihood of using purple drank.


Association of Unintentional Pediatric Exposures With Decriminalization of Marijuana in the United States

George Wang et al.
Annals of Emergency Medicine, March 2014, Pages 1450-1455

Study objective: We compare state trends in unintentional pediatric marijuana exposures, as measured by call volume to US poison centers, by state marijuana legislation status.

Methods: A retrospective review of the American Association of Poison Control Centers National Poison Data System was performed from January 1, 2005, to December 31, 2011. States were classified as nonlegal if they have not passed legislation, transitional if they enacted legislation between 2005 and 2011, and decriminalized if laws passed before 2005. Our hypotheses were that decriminalized and transitional states would experience a significant increase in call volume, with more symptomatic exposures and more health care admissions than nonlegal states.

Results: There were 985 unintentional marijuana exposures reported from 2005 through 2011 in children aged 9 years and younger: 496 in nonlegal states, 93 in transitional states, and 396 in decriminalized states. There was a slight male predominance, and the median age ranged from 1.5 to 2.0 years. Clinical effects varied, with neurologic effects the most frequent. More exposures in decriminalized states required health care evaluation and had moderate to major clinical effects and critical care admissions compared with exposures from nonlegal states. The call rate in nonlegal states to poison centers did not change from 2005 to 2011. The call rate in decriminalized states increased by 30.3% calls per year, and transitional states had a trend toward an increase of 11.5% per year.

Conclusion: Although the number of pediatric exposures to marijuana reported to the National Poison Data System was low, the rate of exposure increased from 2005 to 2011 in states that had passed marijuana legislation.


Effects of Reward Sensitivity and Regional Brain Volumes on Substance Use Initiation in Adolescence

Snežana Urošević et al.
Social Cognitive and Affective Neuroscience, forthcoming

This longitudinal study examines associations between baseline individual differences and developmental changes in reward (i.e., behavioral approach system (BAS)) sensitivity and relevant brain structures' volumes to prospective substance use initiation during adolescence. A community sample of adolescents ages 15 to 18 with no prior substance use was assessed for substance use initiation (i.e., initiation of regular alcohol use and/or any use of other substances) during a two-year follow-up period and for alcohol use frequency in the last year of the follow-up. Longitudinal increases in BAS sensitivity were associated with substance use initiation and increased alcohol use frequency during the follow-up. Moreover, adolescents with smaller left nucleus accumbens (Nacc) at baseline were more likely to initiate substance use during the follow-up period. The present study provides support for the link between developmental increases in reward sensitivity and substance use initiation in adolescence. The study also emphasizes the potential importance of individual differences in volumes of subcortical regions and their structural development for substance use initiation during adolescence.


Development of Impulse Control Circuitry in Children of Alcoholics

Jillian Hardee et al.
Biological Psychiatry, forthcoming

Background: Difficulty with impulse control is heightened in children with a family history of alcohol use disorders and is a risk factor for later substance problems. Cross-sectional fMRI studies have shown altered impulse control processing in family history positive adolescents, yet developmental trajectories have yet to be examined.

Methods: Longitudinal fMRI was conducted in children of alcoholic (FH+; n=43) and control families (FH-; n=30) starting at ages 7-12yr. Participants performed a go/no-go task during fMRI at 1- to 2-yr intervals, with 2-4 scans per subject. We implemented a repeated-measures linear model fit across all subjects to conduct a whole-brain search for developmental differences between groups.

Results: Performance improved with age in both groups and there were no performance differences between groups. Significant between-group differences in linear age-related activation changes were found in the right caudate, middle cingulate, and middle frontal gyrus. Post-hoc analyses revealed significant activation decreases with age in the caudate and middle frontal gyrus for FH- subjects, and a significant increase with age in middle cingulate activation for the FH+ group. Group differences were evident as early as age 7-12yr, even in alcohol and drug naïve participants, with the FH+ group showing significantly blunted activation compared to FH- subjects at baseline.

Conclusions: Differences in response inhibition circuitry are visible as early as childhood in FH+ individuals; this continues into adolescence, displaying trajectories that are inconsistent with normal response inhibition development. These patterns precede problem drinking and may be a contributing factor for subsequent substance problems.


Decreased delay discounting in former cigarette smokers at one year after treatment

Roberto Secades-Villa et al.
Addictive Behaviors, forthcoming

Current cigarette smokers exhibit greater delay discounting relative to ex-smokers. However, few studies have assessed longitudinal changes in delay discounting and cigarette smoking. The purpose of this study was to assess changes in delay discounting of hypothetical monetary rewards and smoking among treatment-seeking smokers (N = 80) at baseline, after 6 weeks of behavioral treatment, and at 12-months follow-up. Results showed no changes in delay discounting in either smokers or abstainers at the end-of-treatment. In contrast, at 12-months follow-up, significant decreases in delay discounting were observed in abstainers while delay discounting remained the same for smokers. To our knowledge, this is the first study to observe significant decreases in delay discounting following prolonged smoking abstinence. Such findings provide evidence that delay discounting may have more state-like characteristics than previously believed.


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