College students' use of cocaine: results from a longitudinal study

Association between ADHD symptoms and illicit stimulants use following 1 year among French university students of the i-Share cohort

PURPOSE

Although attention deficit hyperactivity disorder (ADHD) has been associated with illicit stimulants use, less is known about their prospective association in university students. We aimed to examine the association between ADHD symptoms at inclusion and illicit stimulants use following 1 year among university students.

METHODS

The i-Share cohort recruited French students from February 2013 to July 2020. The study included 4270 participants. The Adult ADHD Self-Report Scale (ASRS) was used to evaluate ADHD symptoms at inclusion. Illicit stimulants use was assessed at inclusion and 1 year after inclusion. Multivariable logistic regressions were conducted to assess the association between ADHD symptoms at inclusion and illicit stimulants use following 1 year.

RESULTS

High levels of ADHD symptoms at inclusion were associated with a greater probability of illicit stimulants use following 1 year (adjusted OR: 2.42 (1.51-3.8)). The adjusted odds ratio was 2.7 (1.08-7.84) among participants who had used illicit stimulant at least once (continuation) and 2.25 (1.04-4.37) among participants who had never used illicit stimulants at inclusion (initiation).

CONCLUSION

High levels of ADHD symptoms are a feature that may promote both initiation and continuation of illicit stimulants use among university students. Our findings suggest that university students with high levels of ADHD symptoms may benefit from screening to help identify those at risk of illicit stimulants use.

An overview of the use of psychoactive substances among students at the University of Lille during the COVID-19 health crisis: Results of the PETRA study

OBJECTIVES

Students represent a population at risk for substance abuse. That risk may have been exacerbated by the COVID-19 pandemic. We aimed to describe substance abuse among students and to compare consumption according to the university field.

METHODS

A self-administered questionnaire was sent by email to all students at the University of Lille, France, between March and July 2021. This anonymous questionnaire included questions about sociodemographic characteristics, university courses and the use of psychoactive substances (frequency, reasons, routes of administration) since the first university year.

RESULTS

Among the 4431 students who responded (response rate 6.1%), eighty percent declared having used alcohol since the first university year, 34% cannabis, 15.4% benzodiazepines, 14.7% opioid drugs, 7.5% cocaine, 6.8% nitrous oxide and 6.5% MDMA. More than 20% of the users of cannabis, benzodiazepines, amphetamines and cocaine reported having already felt dependent. Recreational use was described by more than 10% of benzodiazepine or opioid drug users. Nitrous oxide use was significantly more frequent in the health and sport field (p < 0.001). Tobacco, benzodiazepine, cannabis and MDMA uses were significantly more frequent in the humanities and social sciences/art, language and literature fields (p < 0.001).

CONCLUSION

Prevention measures focusing on alcohol, cannabis, illicit psychostimulants, nitrous oxide and prescription drugs are required in the student population.

Attention deficit hyperactivity disorder symptoms and lifetime use of psychoactive substances among French university students: A cross-sectional study

In a cross sectional study of 13,837 university students, we aimed to explore the association between attention deficit hyperactivity disorder (ADHD) symptoms and lifetime psychoactive substance use (LPSU) on a wide range of illicit substances. Logistic and Hurdel multivariable regressions were used. ADHD symptoms were significantly associated with the lifetime use of ketamine, magic mushrooms, poppers, and nine other psychoactive substances. There was an association between ADHD symptoms and both LPSU and truncated count of lifetime psychoactive substance use. High levels of ADHD symptoms are associated with the use of a large variety and multiple LPSU.

Chronic Cocaine Use and White Matter Coherence: A Diffusion Tensor Imaging Study

OBJECTIVE

Chronic substance use and its effects on brain function and structure has long been of interest to clinicians and researchers. Prior cross-sectional comparisons of diffusion tensor imaging (DTI) metrics have suggested deleterious effects of chronic substance use (i.e., cocaine use) on white matter coherence. However, it is unclear how these effects may replicate across geographic regions when examined with similar technologies. In this study, we sought to conduct a replication of previous work in this area and determine whether there are any patterns of persistent differences in white matter microstructure between individuals with a history of cocaine use disorder (CocUD, according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) and healthy controls.

METHOD

A total of 46 participants (21 healthy controls, 25 chronic cocaine users) were recruited from the Richmond, Virginia metropolitan area. Information regarding past and current substance use was collected from all participants. Participants also completed structural and DTI scans.

RESULTS

Consistent with previous DTI studies, significant differences were found between fractional anisotropy (FA) and axial diffusivity (AD) CocUD and controls, with CocUD showing lower FA and AD in the right inferior and superior longitudinal fasciculus, the genu, body, and splenium of the corpus callosum, and the anterior, posterior, and superior corona radiata, among several other regions. These differences were not significant for other diffusivity metrics. Lifetime alcohol consumption was greater in the CocUD group, but lifetime alcohol consumption did not show a significant linear relationship with any of the DTI metrics in within-group regression analyses.

CONCLUSIONS

These data align with previously reported declines in white matter coherence in chronic cocaine users. However, it is less clear whether comorbid alcohol consumption results in an additive deleterious effect on white matter microstructure.

Sex Differences in Cocaine Sensitization Vary by Mouse Strain

INTRODUCTION

Preclinical literature, frequently utilizing rats, suggests females display a more rapid advancement of substance abuse and a greater risk of relapse following drug abstinence. In clinical populations, it is less clear as to what extent biological sex is a defining variable in the acquisition and maintenance of substance use. Even without considering environmental experiences, genetic factors are presumed to critically influence the vulnerability to addiction. Genetically diverse mouse models provide a robust tool to examine the interactions between genetic background and sex differences in substance abuse.

METHODS

We explored mouse strain variability in male versus female behavioral sensitization to cocaine. Locomotor sensitization was observed following 5 consecutive days of subcutaneous cocaine across three genetically different mice strains: C57BL/6J, B6129SF2/J, and Diversity Outbred (DO/J).

RESULTS

Sex differences in cocaine locomotor sensitization were dependent on mouse strain. Specifically, we observed opposing sex differences in locomotor sensitization, with male C57BL/6J and female B6129SF2/J mice displaying heightened activity compared to their opposite sex counterparts. Conversely, no sex differences were observed in the DO/J mice. Acute cocaine administration resulted in locomotor differences across strains in male, but not female, mice. The magnitude of sensitization (or lack thereof) also varied by genetic background.

CONCLUSIONS

While sex differences in drug addiction may be observed, these effects can be mitigated, or even reversed, depending on genetic background. The clinical implications are that in the absence of understanding the genetic variables underlying vulnerability to addiction, sex provides little information regarding the predisposition of an individual to drug abuse.

Gender differences in cocaine-induced hyperactivity and dopamine transporter trafficking to the plasma membrane

As well known, cocaine induces stimulant effects and dopamine transporter (DAT) trafficking to the plasma membrane of dopaminergic neurons. In the present study, we examined cocaine-induced hyperactivity along with cocaine-induced DAT trafficking and the recovery rate of the dopaminergic system in female rats in comparison with male rats, demonstrating interesting gender differences. Female rats are initially more sensitive to cocaine than male rats in terms of both the DAT trafficking and hyperactivity induced by cocaine. Particularly, intraperitoneal (i.p.) administration of 5 mg/kg cocaine induced significant hyperactivity and DAT trafficking in female rats but not in male rats. After repeated cocaine exposures (i.e., i.p. administration of 20 mg/kg cocaine every other day from Day 0 to Day 32), cocaine-induced hyperactivity in female rats gradually became a clear pattern of two phases, with the first phase of the hyperactivity lasting for only a few minutes and the second phase lasting for over an hour beginning at ~30 min, which is clearly different from that of male rats. It has also been demonstrated that the striatal DAT distribution of female rats may recover faster than that of male rats after multiple cocaine exposures. Nevertheless, despite the remarkable gender differences, our recently developed long-acting cocaine hydrolase, known as CocH5-Fc(M6), can similarly and effectively block cocaine-induced DAT trafficking and hyperactivity in both male and female rats.

Cocaine regulation of Nr4a1 chromatin bivalency and mRNA in male and female mice

Cocaine epigenetically regulates gene expression via changes in histone post-translational modifications (HPTMs). We previously found that the immediate early gene Nr4a1 is epigenetically activated by cocaine in mouse brain reward regions. However, few studies have examined multiple HPTMs at a single gene. Bivalent gene promoters are simultaneously enriched in both activating (H3K4me3 (K4)) and repressive (H3K27me3 (K27)) HPTMs. As such, bivalent genes are lowly expressed but poised for activity-dependent gene regulation. In this study, we identified K4&K27 bivalency at Nr4a1 following investigator-administered cocaine in male and female mice. We applied sequential chromatin immunoprecipitation and qPCR to define Nr4a1 bivalency and expression in striatum (STR), prefrontal cortex (PFC), and hippocampus (HPC). We used Pearson's correlation to quantify relationships within each brain region across treatment conditions for each sex. In female STR, cocaine increased Nr4a1 mRNA while maintaining Nr4a1 K4&K27 bivalency. In male STR, cocaine enriched repressive H3K27me3 and K4&K27 bivalency at Nr4a1 and maintained Nr4a1 mRNA. Furthermore, cocaine epigenetically regulated a putative NR4A1 target, Cartpt, in male PFC. This study defined the epigenetic regulation of Nr4a1 in reward brain regions in male and female mice following cocaine, and, thus, shed light on the biological relevance of sex to cocaine use disorder.

The Role of Beta-Endorphin in Cocaine-Induced Conditioned Place Preference, Its Extinction, and Reinstatement in Male and Female Mice

Endogenous opioids have been implicated in cocaine reward. However, the role of each opioid peptide in this regard is unknown. Notably, the role of each peptide in extinction and reinstatement is not fully characterized. Thus, we assessed whether cocaine-induced conditioned place preference (CPP) and its extinction and reinstatement would be altered in the absence of beta-endorphin. We also examined if sex-related differences would exist in these processes. Male and female mice lacking beta-endorphin and their respective controls were tested for baseline place preference on day 1. On day 2, mice were treated with saline/cocaine (15 mg/kg) and confined to the vehicle- or drug-paired chamber for 30 min, respectively. In the afternoon, mice were treated with the alternate treatment and confined to the opposite chamber. Mice were then tested for CPP on day 3. Mice then received additional conditioning on this day as well as on day 4. Mice were then tested for CPP on day 5. Mice then received extinction training on day 9. On day 10, mice were tested for extinction and then reinstatement of CPP following a priming dose of cocaine (7.5 mg/kg). Male and female mice lacking beta-endorphin did not exhibit CPP following single conditioning with cocaine. On the other hand, only male mice lacking beta-endorphin failed to show CPP after repeated conditioning. Nonetheless, reinstatement of CPP was blunted in both male and female mice lacking beta-endorphin compared to controls. The present results suggest that beta-endorphin plays a functional role in cocaine-induced CPP and its reinstatement, and sex-related differences exist in the regulatory action of beta-endorphin on the acquisition but not reinstatement of cocaine CPP.

Cocaine use in university students: relationships with demographics, mental health, risky sexual practices, and trait impulsivity

BACKGROUND

Cocaine is increasingly used on a recreational basis by the general population with potential implications for mental health. The aim of this study was to assess how common cocaine use is, and its mental health associations, in a large sample of university students.

METHODS

Approximately 10 000 university students were invited to take part in an online survey, which assessed the use of cocaine (ever or past year), alcohol and drug use, mental health issues, and impulsive and compulsive tendencies. Group differences in demographic and clinical characteristics were characterized.

RESULTS

A total of 3520 university students (57.7% female) completed the survey. Of these, 110 students (3.1%) reported using cocaine in the preceding year, and a further 163 students (4.6%) reported historical use more than a year ago. Cocaine use was associated with more years as a student, lower grade point averages, more use of other drugs, riskier sexual practices, post-traumatic stress disorder, attention deficit hyperactivity disorder, treatment for psychological/emotional problems (including taking prescribed medication), and trait impulsivity. Of these associations, the link with trait impulsivity had the largest effect size.

CONCLUSION

History of cocaine use appears relatively common in university students; and has a number of untoward associations in terms of mental health, use of other substances, and risky sexual practices. The most marked finding (in terms of effect size) was the link between cocaine use and trait impulsivity, supporting the importance of this construct in seeking out candidate vulnerability markers for use of cocaine and other drugs. Future work should use longitudinal designs to further characterize the nature of these associations.

Diagnostic sequence of cocaine use disorder in relation to other mental health conditions among college students

Objective: Cocaine use is increasing. Comorbidities and diagnostic sequencing are needed among college students to inform treatment of cocaine use disorder (CUD). Method: Using electronic medical records from the psychiatric clinic at the student health care center of a large, public university from 2005 to 2015, patients diagnosed with CUD were identified. Their top mental health conditions were identified and assessed to see whether the first diagnosis of these conditions was made (1) before, (2) at the same time as, or (3) after the first diagnosis of CUD. Results: Among the 50 CUD patients, their most common mental health comorbidities were alcohol use disorder, anxiety, depression, and cannabis use disorder. Anxiety and depression were likely to be diagnosed before CUD; alcohol and cannabis use disorders were likely to be diagnosed concurrently with CUD. Conclusion: Diagnostic sequencing can be used to inform screening, workup, and treatment for patients with CUD.

Illicit drug use among college students: The role of social norms and risk perceptions

PURPOSE

To examine the prevalence and correlates of college student use of illicit substances including cocaine, designer drugs, and nonmedical use of prescription stimulants and opioids, and to identify how different drug-related perceptions are related to past year use of these substances.

METHODS

Data were analyzed from a cross-sectional anonymous web-based survey among a sample (n = 1345, 81% female) of students attending a mid-sized liberal arts college in the US. Logistic regression models were estimated to assess the relationships between substance-specific descriptive norms, injunctive norms, perceived availability, risk perceptions and past year use of cocaine, designer drugs, prescription stimulants, and opioids, adjusting for current marijuana use, alcohol dependence, sensation seeking, and sociodemographic factors.

FINDINGS

Past year use of illicit substances ranged from 6% for nonmedical prescription opioids to 21% for nonmedical prescription stimulants. The sociodemographic correlates past year substance use differed by substance type. Descriptive norms (perceptions of peer use) and perceived risk were not consistently related to use of these substances. Current marijuana use was the strongest correlate across substances, and both injunctive norms (perceptions of peer approval) and perceived availability were consistently related to use of each substance.

CONCLUSIONS

Findings suggest that future college student drug prevention efforts should more directly target current marijuana users since they are most at risk of using other illicit substances. Additionally, findings indicate that injunctive norms may be an important consideration for education-focused drug prevention programs. However, findings should be interpreted in light of limitations of the sample, which is predominantly female.

Xlr4 as a new candidate gene underlying vulnerability to cocaine effects

Although several studies have been performed in rodents, non-human primates and humans, the biological basis of vulnerability to develop cocaine addiction remains largely unknown. Exposure to critical early events (as Repeated Cross Fostering (RCF)) has been reported to increase sensitivity to cocaine effects in adult C57BL/6J female mice. Using a microarray approach, here we report data showing a strong engagement of X-linked lymphocyte-regulated 4a and 4b (Xlr4) genes in cocaine effects. The expression of Xlr4, a gene involved in chromatin remodeling and dendritic spine morphology, was reduced into the Nucleus Accumbens (NAc) of adult RCF C57BL/6J female. We used virally mediated accumbal Xlr4 down-modulation (AAVXlr4-KD) to investigate the role of this gene in vulnerability to cocaine effects. AAVXlr4-KD animals show a potentiated behavioral and neurochemical response to cocaine, reinstatement following cocaine withdrawal and cocaine-induced spine density alterations in the Medium-Sized Spiny Neurons of NAc. We propose Xlr4 as a new candidate gene mediating the cocaine effects.

Self-Reported Illicit Drug Use Among Norwegian University and College Students. Associations With Age, Gender, and Geography

Background and Aims: Several studies have pointed to relatively high levels of illicit drug use among students in higher education compared to the general population. The aim of the present study was to provide an updated examination of self-reported illicit drug use among Norwegian University and college students. Methods: Data stem from the SHoT study (Students' Health and Well-being Study), a nationwide cross-sectional survey for higher education in Norway including Norwegian full-time students aged 18-35. Self-reported illicit drug use across a range of specified drugs comprised the outcome variables. Information on gender, age, and study location (geographical area) was also collected and used as stratification variables. The SHoT-survey from 2018 (N = 50,054) was used for the analyses of associations between demographical variables and illicit drug use, while trends in illicit drug use were estimated by comparing the 2018-results with data from the SHoT-surveys conducted in 2010 and 2014. Results: The proportion of students reporting having ever tried illicit drugs increased from 2014 to 2018, for both males (30.8 vs. 36.7%) and females (17.5 vs. 24.0%, both p < 0.001), while only minimal changes occurred between 2010 and 2014. The most commonly used illicit drugs during the past 12 months in 2018 were cannabis (15.2%), followed by MDMA (4.0%), cocaine (3.0%), and LSD/psilocybin (2.1%). Illicit drug use showed both linear increase with age, and inverted U-shaped relationships that peaked in the age span from 23 to 28 years of age. Males reported higher illicit drug use compared with females for all drugs. Proportions of illicit drug use varied across geographical areas within the country, with the highest use being reported in the Oslo area (the largest city and capital of Norway). Conclusions: The present study reports an increase from 2010 to 2018 among Norwegian University and college students in the proportion of those reporting to have tried illicit drugs. Despite varying proportions of use across type of drug, age, gender, and geographical location, the overall high levels of illicit drug use past 12 months confirm the need to address illicit drug use in this population.

Cocaine use is declining among emerging adults in the United States: Trends by college enrollment

BACKGROUND

The difference in cocaine use between student and non-student emerging adults is not well understood, despite the longstanding assumption that college is protective against use.

OBJECTIVE

To describe trends in cocaine use among emerging adults by college enrollment.

METHODS

Using cross-sectional, nationally-representative data from the National Survey on Drug Use and Health (2002-2016), we estimated the prevalence of four cocaine use indicators by year among emerging adults (ages 18-22) and stratified by college enrollment. We tested for linear and quadratic trends over time.

RESULTS

From 2002 to 2016, 11.7% reported lifetime cocaine use, 5.8% reported past 12-month use, 1.7% reported past 30-day use, and 1% had a use disorder in the past 12-months. We observed significant linear decreases in all four use indicators over time (Lifetime: β = -0.20, Past 12-months: β = -0.17, Past 30-days: β = -0.22, Past 12-months disorder: β = -0.37). Students had lower rates of cocaine use than non-students, although prevalence estimates were more similar between groups for past 12-month (Students:5.3%, 95% CI:5.0-5.5; Non-students:6.3%, 95% CI:6.1-6.5) and past 30-day use (Students:1.6%, 95% CI:1.4-1.7; Non-students:1.8%, 95% CI:1.7-1.9) than for lifetime use (Students:9.4%, 95% CI:9.1-9.7; Non-students:13.8%, 95% CI:13.5-14.1).

CONCLUSIONS

Cocaine use has declined among emerging adults since the early 2000s. The college environment appears compensate for early life differences in cocaine use risk between students and non-students, closing the gap between groups for recent indicators of cocaine use. Given the severe health consequences associated with cocaine use, more public health attention to this issue is needed.

Modulation of striatal dopamine dynamics by cocaine self-administration and amphetamine treatment in female rats

Despite decades of research into the neurobiological basis of cocaine abuse, pharmacotherapeutic treatments for cocaine addiction have been largely ineffective. Converging evidence from preclinical research and from outpatient clinical trials suggest that treatment with amphetamine is efficacious in reducing cocaine intake. Although it has been suggested that amphetamine treatment reduces cocaine intake as an agonist replacement therapy, we have shown recently that multiple aspects of dopamine signaling are altered by cocaine self-administration and returned to pre-cocaine function by amphetamine treatment in the nucleus accumbens of male rats. Here, we sought to determine if these effects were also evident in female subjects, and across regions of the striatum. Female rats performed 5 days of cocaine self-administration (1.5 mg kg^-1  inj^-1 , 40 inj/day) and were treated with a single amphetamine (0.56 mg/kg) or saline infusion 1 hr prior to killing. We then used ex vivo fast-scan cyclic voltammetry in the nucleus accumbens core or dorsolateral caudate-putamen to examine dopamine signaling and cocaine potency. We found that in the nucleus accumbens core, cocaine self-administration decreased dopamine uptake rate and cocaine potency, and both alterations were restored by amphetamine treatment. In the dorsolateral caudate-putamen, neither cocaine self-administration nor amphetamine treatment altered dopamine uptake; however, cocaine potency was decreased by self-administration and returned to control levels by amphetamine. Together, these findings support a role for amphetamine treatment for cocaine addiction outside of agonist replacement therapy, and suggest that the development of cocaine tolerance is similar across sexes.

Substance Use Among College Students

U.S. college campuses have witnessed a national increase of cannabis, stimulant, and illicit drug use among students over the past decade. Substance use among college students is associated with numerous negative outcomes including lower academic performance, a higher probability of unemployment after graduation, and an increased risk of committing and experiencing sexual assault. Several risk factors for substance use are specific to this population, including an affiliation with Greek life, perception of high academic pressure, and peer pressure. Students with problematic substance use also face unique challenges in planning treatment, including aspects of confidentiality, financial constraints, and potential university oversight and involvement. This article highlights the prevalence of substance use on college campuses and describes some of the specific challenges and approaches to treatment in this population, including screening tests and interventions for specific substances used on college campuses and evidence-based substance use programming for college students.

Illict drug use and academia in North Kosovo: Prevalence, patterns, predictors and health-related quality of life

PURPOSE

The purpose of this study were to estimate the prevalence and patterns of illicit drug use in a sample of University students from North Kosovo, to assess factors associated with illicit drug use and to assess health-related quality of life (HRQoL) among students according to illicit drug use.

METHODS

A cross-sectional study was conducted at the Student Public Health Center, where 514 University students were enrolled from April to June 2015 in North Kosovo. Participants completed the general socio-demographic and behavioral questionnaire, Beck Depression Inventory (BDI) and the SF-36 questionnaire for HRQoL assessment. Data on lifetime illicit drug use were self-reported.

RESULTS

As much as 16.0% of students reported ever illicit drug use. The most frequently used drugs were marijuana (9.3%) and bromazepam (7.6%). Factors associated with ever illicit drug use were: being smoker and alcohol user, having chronic diseases and having higher depressive symptoms score. Ever illicit drug users reported all domains of HRQoL as worse.

CONCLUSION

These results could serve as a tool for implementation of preventive strategies and University policies to promote healthy lifestyles and behaviors. Measurement of HRQoL could also be used as indicator of the effect of interventions designed to reduce and/or prevent illicit drug use at institutions of higher education.

Trends and correlates of cocaine use and cocaine use disorder in the United States from 2011 to 2015

BACKGROUND

Recent epidemiological data suggest a resurgence in cocaine use (CU) and cocaine-related problems in the United States. Demographic trends and correlates of problem CU are needed to determine potential factors that may be influencing the increased trend and to inform targeted prevention and intervention strategies.

METHODS

Trends in any past-year CU, weekly CU, and cocaine use disorder (CUD) were examined among persons aged ≥12 years using the National Survey on Drug Use and Health from 2011 to 2015. Logistic regression analyses were used to determine correlates of past-year and weekly CU and CUD among adolescents and adults.

RESULTS

The prevalence of past-year CU from 2011 to 2015 increased among females, ages 18-25, ages ≥50, non-Hispanic Blacks, and persons reporting low income, past-year tobacco use, past-year alcohol use, and past-month binge and heavy alcohol use. The prevalence of weekly CU increased among persons aged ≥50 years and persons reporting past-month heavy alcohol use. A significant increase in the prevalence of CUD was only found among persons aged ≥50 years. Adjusted logistic regression showed that older age, large metropolitan residence, past-year tobacco, alcohol, cannabis, and heroin use, and major depressive episode were associated with increased odds of CU or CUD among both adolescents and adults; however, sex and race/ethnicity correlates differed among adolescents and adults.

CONCLUSIONS

Findings have implications for increased monitoring of CU-related indicators among some high-risk groups, such as females, older adults, Blacks, and polysubstance users. Targeted screening and intervention strategies among these population subgroups may be needed.

Substance Use Trajectories From Early Adolescence Through the Transition to College

OBJECTIVE

The transition to college is an important developmental period for the development of alcohol, marijuana, and hard drug (cocaine, opiates, inhalants, stimulants, hallucinogens, Ecstasy, club drugs) use. The current study explored specific changes in substance use patterns during and after the transition to college through the use of trajectory analyses.

METHOD

Participants were 526 students who reported retrospectively and prospectively on their substance use from age 13 through the junior year of college. Group-based trajectory modeling was used to estimate developmental trajectory groups for alcohol, marijuana, and hard drug use during this period.

RESULTS

Results supported a five-group model of alcohol use, a four-group model of marijuana use, and a four-group model of hard drug use. Although three of the five alcohol trajectories indicated high escalation throughout adolescence, one of these groups decreased in alcohol use dramatically during the freshman and sophomore years, a trend also found for hard drug use. Trajectories demonstrated significant differences in terms of gender, race, and impulsive personality characteristics.

CONCLUSIONS

These results indicate that the start of college is an important developmental transition in terms of polysubstance use, and that despite the homogeneity of this undergraduate sample, there is considerable divergence in trajectories during college.

Drug involvement during and after college: Estimates of opportunity and use given opportunity

BACKGROUND

College students perceive widespread availability of drugs and prescription medications for non-medical use on campus, but less is known about the relationship between opportunity to use, use, and use given opportunity of these drugs during and after college. The current study describes annual trends in (1) opportunity to use, (2) use, and (3) use given opportunity of eight drugs and three prescription medications used non-medically over seven years.

METHODS

Data were derived from a longitudinal cohort study of 1253 first-year college students (52% female, 72% non-Hispanic white) at one large, public university. Annually, past-year opportunity to use and use were assessed for marijuana, hallucinogens, inhalants, cocaine, ecstasy, amphetamines, methamphetamine, heroin, and non-medical use of prescription stimulants, analgesics, and tranquilizers. Binary variables were created to represent opportunity to use, use, and use given opportunity for each drug.

RESULTS

Participants had the greatest opportunity to use marijuana compared with other drugs during the study period, but there was a significant decline in the opportunity to use marijuana over time. Notably, opportunity for both drugs other than marijuana and prescription medications used non-medically consistently declined, while use given opportunity remained relatively stable over time.

CONCLUSIONS

These findings suggest that changes in drug use are driven by changes in opportunity to use, even during the post-college years. Greater opportunity to use and use of all drugs during the college years in comparison with the post-college years confirms the high-risk nature of the college environment.

Prevalence and incidence of drug use among college students: an 8-year longitudinal analysis

BACKGROUND

Drug use among college students is associated with adverse academic and health outcomes and risks to personal safety.

OBJECTIVES

This study utilized data from a longitudinal study to estimate annual prevalence, cumulative lifetime prevalence, and incidence of ten types of drug use during the eight years after college entry and the average age of onset of each drug used.

METHODS

Participants (N = 1,253; 52% female) were young adults who were originally enrolled as first-time, first-year students at a university in the mid-Atlantic US. Annual personal interviews gathered data about the use of seven illicit drugs and three prescription drugs used nonmedically. Annual follow-up rates ranged from 76 to 91%.

RESULTS

Marijuana was the most commonly used drug in every year of the study, with the highest annual prevalence estimates in Year 3 (47%_wt). In Year 8, when the modal age of participants was 25, 29%_wt used marijuana during the past year. Nonmedical use of prescription drugs was more prevalent during college than in the later years of the study. Although the prevalence of cocaine and ecstasy use was low (cumulative prevalence estimates of 17%_wt and 13%_wt, respectively), incidence for these drugs was particularly high in the later years of the study.

CONCLUSION

Drug use is prevalent among college students, and drug use persists among young adults, even after many have graduated college. More attention should be directed at identifying and intervening with students at risk for drug use to mitigate possible academic, health, and safety consequences.

Dopaminergic dynamics underlying sex-specific cocaine reward

Although both males and females become addicted to cocaine, females transition to addiction faster and experience greater difficulties remaining abstinent. We demonstrate an oestrous cycle-dependent mechanism controlling increased cocaine reward in females. During oestrus, ventral tegmental area (VTA) dopamine neuron activity is enhanced and drives post translational modifications at the dopamine transporter (DAT) to increase the ability of cocaine to inhibit its function, an effect mediated by estradiol. Female mice conditioned to associate cocaine with contextual cues during oestrus have enhanced mesolimbic responses to these cues in the absence of drug. Using chemogenetic approaches, we increase VTA activity to mechanistically link oestrous cycle-dependent enhancement of VTA firing to enhanced cocaine affinity at DAT and subsequent reward processing. These data have implications for sexual dimorphism in addiction vulnerability and define a mechanism by which cellular activity results in protein alterations that contribute to dysfunctional learning and reward processing.

Sex differences in reward processing are at present poorly understood. Calipari and Juarez et al. report oestrous cycle-dependent fluctuations in firing of VTA dopamine neurons that drive alterations in DAT function expressed in terminals in the NAc. These differences underlie enhanced cocaine reward processing during oestrus.

(Mis)use of Prescribed Stimulants in the Medical Student Community: Motives and Behaviors: A Population-Based Cross-Sectional Study

The aim of this study was to estimate the prevalence of psychostimulant use in the French medical community and their motives. A population-based cross-sectional study using a self-administered online survey was done. A total of 1718 French students and physicians (mean age, 26.84±7.19 years, 37.1% men) were included. Self-reported lifetime use, motives, socio-demographic and academic features for over the counter (OTC), medically prescribed (MPP), and illicit (IP) psychostimulant users were reported. Lifetime prevalence of psychostimulant use was 33% (29.7% for OTC, 6.7% for MPP, and 5.2% for IP). OTC consumption mainly aimed at increasing academic performance and wakefulness during competitive exams preparation. OTC consumption started early and was predictive of later MPP use. Corticoids were the most frequently consumed MPP (4.5%) before methylphenidate and modafinil. Motives for MPP consumption were increased academic performance, concentration, memory, and wakefulness. Psychostimulant use is common among French medical community. Our results suggest that restrictions on methylphenidate and modafinil prescriptions are effective at limiting their use. However, these restrictions may explain the observed rates of corticoids consumption, which raise a new public health problem, given that corticoids may have severe side effects.

Transitioning from First Drug Use to Dependence Onset: Illustration of a Multiparametric Approach for Comparative Epidemiology

Studying transitions from first drug use (DU) to drug dependence (DD) onset, we estimate a parsimonious set of parameters based on epidemiological data, with plans for future longitudinal research on newly incident drug users and with tracking of self-administration frequencies and DD clinical features. Our expectation is a distinctive sigmoid pattern with one asymptote for lower DD probability (when DU is insubstantial), upturning slopes of DD risk beyond a middle value (PD50), and eventual higher DD risk asymptotes at higher DU frequencies. We illustrate this novel approach using cross-sectional data from the United States National Surveys on Drug Use and Health, 2002-2011. Empirical DD probabilities observed soon after newly incident use are estimated across DU frequency values, using parametric Hill functions and four governing parameters for differential comparison across drugs and DU subgroups. Among drug subtypes considered, cocaine shows larger estimates, especially among females (estimated P(min)=7% for females vs 3% for males; p<0.001), for whom PD50 is shorter by 8 days of use (p=0.027), conditional on the same rate of use in the past 30 days. Clear alcohol male-female differences also are observed (eg, female PD50 < male PD50; p=0.002). Although based on cross-sectional snapshots soon after DU onset, this novel multiparametric statistical approach for comparative epidemiological DD research creates new opportunities in planned studies with prospectively gathered longitudinal data. The cross-sectional estimates provide starting values needed to plan future longitudinal research programs on transitions from initial DU until formation of a DD syndrome.

The Nociceptin Receptor as an Emerging Molecular Target for Cocaine Addiction

Cocaine addiction is a global public health and socioeconomic issue that requires pharmacological and cognitive therapies. Currently there are no FDA-approved medications to treat cocaine addiction. However, in preclinical studies, interventions ranging from herbal medicine to deep-brain stimulation have shown promise for the therapy of cocaine addiction. Recent developments in molecular biology, pharmacology, and medicinal chemistry have enabled scientists to identify novel molecular targets along the pathways involved in drug addiction. In 1994, a receptor that showed a great deal of homology to the traditional opioid receptors was characterized. However, endogenous and exogenous opioids failed to bind to this receptor, which led scientists to name it opioid receptor-like receptor, now referred to as the nociceptin receptor. The endogenous ligand of NOPr was identified a year later and named orphanin FQ/nociceptin. Nociceptin and NOPr are widely distributed throughout the CNS and are involved in many physiological responses, such as food intake, nociceptive processing, neurotransmitter release, etc. Furthermore, exogenous nociceptin has been shown to regulate the activity of mesolimbic dopaminergic neurons, glutamate, and opioid systems, and the stress circuit. Importantly, exogenous nociceptin has been shown to reduce the rewarding and addictive actions of a number of drugs of abuse, such as psychostimulants, alcohol, and opioids. This paper reviews the existing literature on the role of endogenous nociceptin in the rewarding and addictive actions of cocaine. The effect of exogenous nociceptin on these processes is also reviewed. Furthermore, the effects of novel small-molecule NOPr ligands on these actions of cocaine are discussed. Overall, a review of the literature suggests that NOPr could be an emerging target for cocaine addiction pharmacotherapy.

Demographic and psychological factors associated with lifetime cocaine use: An exploratory factor analysis of baseline questionnaires

OBJECTIVES

Underlying heterogeneity among individuals with cocaine dependence is widely postulated in the literature, however, identification of a group of factors that explain risk of cocaine use severity has yet to be confirmed.

METHODS

Latent mixture modeling evaluated 338 cocaine-dependent individuals recruited from the community to assess the evidence for the presence of distinct subgroups. Variables included 5 baseline questionnaires measuring cognitive function (Shipley), impulsivity (BIS), mood (BDI), affective lability (ALS), and addiction severity (ASI). Results failed to suggest multiple subgroups. Given a lack of evidence for discrete latent classes, an exploratory factor analysis (EFA) followed by exploratory structural equation modeling (ESEM) was implemented to identify functional dimensions to enhance interpretation of these variables.

RESULTS

Findings from the EFA indicated a 3-factor model as the best fit, and the subsequent ESEM solution resulted in associations with lifetime cocaine use. Factor 1, best characterized by demographic factors (gender, age), is associated with less lifetime cocaine use. Psychological problems best characterize factor 2, which is associated with higher lifetime cocaine use. Finally, factor 3 is characterized by other substance use (alcohol and marijuana). Although this factor did not demonstrate a statistically reliable relation with self-reported, lifetime cocaine use, it did indicate a potentially meaningful positive association.

CONCLUSIONS

These 3 factors delineate dimensions of functioning that likewise help characterize the variability found in previously established associations with self-reported cocaine use.

Powder cocaine and crack use in the United States: an examination of risk for arrest and socioeconomic disparities in use

BACKGROUND

In light of the current sentencing disparity (18:1) between crack and powder cocaine possession in the United States, we examined socioeconomic correlates of use of each, and relations between use and arrest, to determine who may be at highest risk for arrest and imprisonment.

METHODS

We conducted secondary data analyses on the National Survey on Drug Use and Health, 2009-2012. Data were analyzed for adults age ≥ 18 to determine associations between use and arrest. Socioeconomic correlates of lifetime and annual use of powder cocaine and of crack were delineated using multivariable logistic regression and correlates of frequency of recent use were examined using generalized negative binomial regression.

RESULTS

Crack users were at higher risk than powder cocaine users for reporting a lifetime arrest or multiple recent arrests. Racial minorities were at low risk for powder cocaine use and Hispanics were at low risk for crack use. Blacks were at increased risk for lifetime and recent crack use, but not when controlling for other socioeconomic variables. However, blacks who did use either powder cocaine or crack tended to use at higher frequencies. Higher education and higher family income were negatively associated with crack use although these factors were sometimes risk factors for powder cocaine use.

CONCLUSIONS

Crack users are at higher risk of arrest and tend to be of lower socioeconomic status compared to powder cocaine users. These findings can inform US Congress as they review bills (e.g., The Smarter Sentencing Act), which would help eliminate cocaine-related sentencing disparities.

Cocaine-induced sensitization correlates with testosterone in male Japanese quail but not with estradiol in female Japanese quail

Research has indicated that gonadal hormones may mediate behavioral and biological responses to cocaine. Estrogen, in particular, has been shown to increase behavioral responding to cocaine in female rats relative to male rats. The current study investigated the effect of cocaine on locomotor activity and hormonal correlates in male and female Japanese quail (Coturnix japonica). In Japanese quail, circulating hormone levels can be manipulated without surgical alterations via modifying the photoperiod. Male and female quail were housed on either 8L:16D (light:dark) or 16L:8D (light:dark) cycle for 21days. Blood samples were taken prior to the beginning of the experiment and assays were performed to determine the levels of testosterone (T) and estradiol (E2). Quail were given injections of saline or cocaine (10 or 20mg/kg) once a day for 10days. Immediately after each injection, birds were placed in open field arenas and distance traveled was measured for 30min. Results showed that male quail housed under long-light conditions exhibited cocaine-induced sensitization to 10mg/kg cocaine which was correlated with the high levels of plasma T. Female quail housed under short-light conditions demonstrated sensitization to 10mg/kg cocaine, but this was not correlated with the levels of plasma E2. The current findings suggest that cocaine-induced locomotor activity was associated with T in males but not with E2 in females.

Performance on a strategy set shifting task in rats following adult or adolescent cocaine exposure

RATIONALE

Neuropsychological testing is widespread in adult cocaine abusers, but lacking in teens. Animal models may provide insight into age-related neuropsychological consequences of cocaine exposure.

OBJECTIVES

The objective of the present study is to determine whether developmental plasticity protects or hinders behavioral flexibility after cocaine exposure in adolescent vs. adult rats.

METHODS

Using a yoked-triad design, one rat controlled cocaine delivery and the other two passively received cocaine or saline. Rats controlling cocaine delivery (1.0 mg/kg) self-administered for 18 sessions (starting P37 or P77), followed by 18 drug-free days. Rats next were tested in a strategy set shifting task, lasting 11-13 sessions.

RESULTS

Cocaine self-administration did not differ between age groups. During initial set formation, adolescent-onset groups required more trials to reach criterion and made more errors than adult-onset groups. During the set shift phase, rats with adult-onset cocaine self-administration experience had higher proportions of correct trials and fewer perseverative + regressive errors than age-matched yoked-controls or rats with adolescent-onset cocaine self-administration experience. During reversal learning, rats with adult-onset cocaine experience (self-administered or passive) required fewer trials to reach criterion, and the self-administering rats made fewer perseverative + regressive errors than yoked-saline rats. Rats receiving adolescent-onset yoked-cocaine had more trial omissions and longer lever press reaction times than age-matched rats self-administering cocaine or receiving yoked-saline.

CONCLUSIONS

Prior cocaine self-administration may impair memory to reduce proactive interference during set shifting and reversal learning in adult-onset but not adolescent-onset rats (developmental plasticity protective). Passive cocaine may disrupt aspects of executive function in adolescent-onset but not adult-onset rats (developmental plasticity hinders).

Rate of progression from first use to dependence on cocaine or opioids: a cross-substance examination of associated demographic, psychiatric, and childhood risk factors

BACKGROUND

A number of demographic factors, psychiatric disorders, and childhood risk factors have been associated with cocaine dependence (CD) and opioid dependence (OD), but little is known about their relevance to the rate at which dependence develops. Identification of the subpopulations at elevated risk for rapid development of dependence and the risk factors that accelerate the course of dependence is an important public health goal.

METHODS

Data were derived from cocaine dependent (n=6333) and opioid dependent (n=3513) participants in a multi-site study of substance dependence. Mean age was approximately 40 and 40% of participants were women; 51.9% of cocaine dependent participants and 29.5% of opioid dependent participants self-identified as Black/African-American. The time from first use to dependence was calculated for each substance and a range of demographic, psychiatric, and childhood risk factors were entered into ordinal logistic regression models to predict the (categorical) transition time to CD and OD.

RESULTS

In both the cocaine and opioid models, conduct disorder and childhood physical abuse predicted rapid development of dependence and alcohol and nicotine dependence diagnoses were associated with slower progression to CD or OD. Blacks/African Americans were at greater risk than European Americans to progress rapidly to OD.

CONCLUSIONS

Only a subset of factors known to be associated with CD and OD predicted the rate at which dependence developed. Nearly all were common to cocaine and opioids, suggesting that sources of influence on the timing of transitions to dependence are shared across the two substances.

Demographic and socioeconomic correlates of powder cocaine and crack use among high school seniors in the United States

OBJECTIVES

Rates of powder cocaine and crack use have fluctuated among adolescents over recent decades. Little attention has been paid to recent trends, particularly regarding differences between users of powder cocaine and crack-two forms of the substance that are commonly reported together as "cocaine" use, despite having different effects and rates of adverse outcomes.

METHODS

We examined data from nationally representative samples of high school seniors who participated in the Monitoring the Future study during years 2005-2011 (weighted N = 65 717).

RESULTS

Many demographic and socioeconomic variables were similarly correlated with lifetime use of powder cocaine and crack. Income of >$50/week from job increased the odds for use, and income of >$50/week from sources other than a job more than doubled the odds for use. High religiosity, high parent education, identifying as black, and residing with one or two parents reduced odds for use. Hispanic students were at higher odds for use of crack and females were at lower odds for using powder cocaine. Among cocaine users, residing with one or two parents lowered odds for using both forms, and more religious students and Hispanics were at higher odds for crack-only use.

CONCLUSIONS

Those interested in preventing initiation and adverse consequences of cocaine use should take into account the overlapping, yet different risk profiles of powder cocaine and crack users when developing programming. This is particularly important when considering differences in legal consequences for these pharmacologically similar forms of cocaine.

Young adults at risk for stimulant dependence show reward dysfunction during reinforcement-based decision making

BACKGROUND

While stimulant-dependent individuals continue to make risky decisions, in spite of poor outcomes, much less is known about decision-making characteristics of occasional stimulant users (OSU) at risk for developing stimulant dependence. This study examines whether OSU exhibit inefficient learning and execution of reinforced decision-outcome contingencies.

METHODS

Occasional stimulant users (n = 161) and stimulant-naïve comparison subjects (CTL) (n = 48) performed a Paper Scissors Rock task during functional magnetic resonance imaging. Selecting a particular option was associated with a predetermined probability of winning, which was altered repeatedly to examine neural and behavioral characteristics of reinforced contingencies.

RESULTS

Occasional stimulant users displayed greater anterior insula, inferior frontal gyrus, and dorsal striatum activation than CTL during late trials when contingencies were familiar (as opposed to being learned) in the presence of comparable behavioral performance in both groups. Follow-up analyses demonstrated that during late trials: 1) OSU with high cannabis use displayed greater activation in these brain regions than CTL, whereas OSU with low cannabis use did not differ from the other two groups; and 2) OSU preferring cocaine exhibited greater anterior insula, inferior frontal gyrus, and dorsal striatum activation than CTL and also displayed higher activation in the former two regions than OSU who preferred prescription stimulants.

CONCLUSIONS

Occasional stimulant users exhibit inefficient resource allocation during the execution of reinforced contingencies that may be a result of additive effects of cocaine and cannabis use. A critical next step is to establish whether this inefficiency predicts transition to stimulant dependence.

Drug use patterns and continuous enrollment in college: results from a longitudinal study

OBJECTIVE

Few longitudinal studies have examined the relationship between illicit drug use and academic outcomes among college students. This study characterized drug use patterns of a cohort of young adults who were originally enrolled as first-time, first-year college students in a longitudinal study. It evaluated the association between these drug use patterns and continuous enrollment during college, holding constant demographic characteristics, high school grade point average, fraternity/sorority involvement, personality/temperament characteristics, nicotine dependence, and alcohol use disorder.

METHOD

Participants (n = 1,133; 47% male) were purposively selected from one university and interviewed annually for 4 years, beginning with their first year of college, regardless of continued college attendance. Enrollment data were culled from administrative records. Group-based trajectory analyses characterized 4-year longitudinal drug use patterns. Two grouping variables were derived based on (a) marijuana use frequency and (b) number of illicit drugs used other than marijuana. Seventy-one percent of the sample was continuously enrolled in the home institution during the first 4 years of study.

RESULTS

Multivariable logistic regression models demonstrated that infrequent, increasing, and chronic/heavy marijuana use patterns were significantly associated with discontinuous enrollment (adjusted odds ratio = 1.66, 1.74, and 1.99, respectively), compared with minimal use, holding constant covariates. In separate models, drug use other than marijuana also was significantly associated with discontinuous enrollment.

CONCLUSIONS

Marijuana use and other illicit drug use are both associated with a decreased likelihood of continuous enrollment in college, independent of several other possible risk factors. These findings highlight the need for early intervention with illicit drug users to mitigate possible negative academic consequences.

Drug use patterns in young adulthood and post-college employment

BACKGROUND

The relationship between serious drug involvement and risk for unemployment is well recognized, but few studies have prospectively examined this relationship among college students. This study used longitudinal data to examine the association between drug use patterns during college and the likelihood of employment post-college, holding constant sociodemographic variables and personality characteristics. Second, we estimate the prevalence of alcohol and other drug use disorders among employed individuals.

METHODS

Data were derived from the College Life Study. Participants entered college as traditional students and were assessed annually for six years, regardless of continued college attendance. Analyses were restricted to 620 individuals no longer enrolled in school by Year 6.

RESULTS

Using multinomial regression modeling, persistent drug users (i.e., used illicit drugs (other than marijuana) and/or nonmedical prescription drugs every year they were assessed during the first four years of study) were significantly more likely than non-users to be unemployed vs. employed full-time post-college. Persistent drug users and infrequent marijuana users were also more likely than non-users to be unemployed vs. employed part-time. In Year 6, 13.2% of individuals employed full-time and 23.7% of individuals employed part-time met DSM-IV criteria for drug abuse or dependence during the past year.

CONCLUSIONS

If confirmed, the results of this study suggest that persistent drug use among academically achieving young adults might increase risk for post-college unemployment. More research is needed to understand the processes underlying this association. Further attention should be directed at managing substance use problems among recent college graduates who have secured employment.

The influence of uncertainty and social support on information seeking concerning illicit stimulant use among young adults

Using the Theory of Motivated Information Management (TMIM) and the concept of desired informational support as a framework, this project examined factors in the information management process young adults employ in potential information seeking about illicit stimulant drug use with members of their social networks. One hundred and seventy-three individuals participated in the study. Results indicated that (a) uncertainty discrepancy and the desire for informational support covaried, and (b) uncertainty discrepancy, anxiety, and outcome expectancy had significant impacts on the efficacy judgments made by individuals with regard to potential information seeking with their social networks about their stimulant drug use. The study thus provides further evidence for the utility of TMIM as a framework for understanding health communication in regard to drug use, and suggests that desired informational support may be a useful addition to the model for this health issue.