Neural correlates of verbal learning in adolescent alcohol and marijuana users

Aims Alcohol and marijuana are the most widely used intoxicants among adolescents, yet their potential unique and interactive influences on the developing brain are not well established. Brain regions subserving learning and memory undergo continued maturation during adolescence, and may be particularly susceptible to substance‐related neurotoxic damage. In this study, we characterize brain response during verbal learning among adolescent users of alcohol and marijuana. Design Participants performed a verbal paired associates encoding task during functional magnetic resonance imaging (fMRI) scanning. Setting Adolescent subjects were recruited from local public schools and imaged at a university‐based fMRI center. Participants Participants were 74 16–18‐year‐olds, divided into four groups: (i) 22 controls with limited alcohol and marijuana experience, (ii) 16 binge drinkers, (iii) eight marijuana users and (iv) 28 binge drinking marijuana users. Measurements Diagnostic interview ensured that all teens were free from neurological or psychiatric disorders; urine toxicology and breathalyzer verified abstinence for 22–28 days before scanning; a verbal paired associates task was administered during fMRI. Findings Groups demonstrated no differences in performance on the verbal encoding task, yet exhibited different brain response patterns. A main effect of drinking pointed to decreased inferior frontal but increased dorsal frontal and parietal fMRI response among binge drinkers (corrected P < 0.05). There was no main effect of marijuana use. Binge drinking × marijuana interactions were found in bilateral frontal regions (corrected P < 0.05), where users of either alcohol or marijuana showed greater response than non‐users, but users of both substances resembled non‐users. Conclusions Adolescent substance users demonstrated altered fMRI response relative to non‐using controls, yet binge drinking appeared to be associated with more differences in activation than marijuana use. Alcohol and marijuana may have interactive effects that alter these differences, particularly in prefrontal brain regions.     

Hair testing and self-report of cocaine use by heroin users

Aim Failure to disclose cocaine use can have a negative impact on medical care and research validity. This study was performed to identify predictors of cocaine non‐disclosure among individuals who self‐reported heroin use during a medical care encounter. Design A prospective comparison of self‐report of cocaine use among heroin users and hair analysis for cocaine. Setting Four health‐care clinics at an academic, inner‐city hospital. Participants Patients presenting for a health‐care visit who were willing to self‐report use of heroin and were not engaged in any form of drug treatment. Measurements (1) Self‐report using standardized instruments: the Drug Addiction Severity Test (DAST), the Addiction Severity Index (ASI) and quantity/frequency questions for heroin and cocaine use. (2) Biochemical evidence: analysis of hair by radioimmunoassay (RIA) for cocaine and opiate levels. Findings Among 336 heroin users who tested positive for cocaine in hair, 34.2% did not report their recent cocaine use. The mean cocaine level for discordant individuals was significantly lower than for concordant individuals (109.6 ng/10 mg versus 470.57 ng/10 mg; P < 0.0001). Multivariate predictors of disclosure included opiate and cocaine levels in hair and the ASI drug severity subscore. Conclusions Although self‐report has been validated for treatment system patients, almost a third of the out‐of‐treatment heroin users in this medical clinic study failed to disclose concomitant cocaine use. The likelihood of non‐disclosure was greatest for heavy users of heroin and light users of cocaine. Confirmation of self‐report with biochemical analysis in the medical setting may be necessary to improve both clinical care and research validity.     

Medical marijuana laws and adolescent marijuana use in the United States: a systematic review and meta‐analysis

Aims

To conduct a systematic review and meta‐analysis of studies in order to estimate the effect of US medical marijuana laws (MMLs) on past‐month marijuana use prevalence among adolescents.

Methods

A total of 2999 papers from 17 literature sources were screened systematically. Eleven studies, developed from four ongoing large national surveys, were meta‐analyzed. Estimates of MML effects on any past‐month marijuana use prevalence from included studies were obtained from comparisons of pre–post MML changes in MML states to changes in non‐MML states over comparable time‐periods. These estimates were standardized and entered into a meta‐analysis model with fixed‐effects for each study. Heterogeneity among the study estimates by national data survey was tested with an omnibus F‐test. Estimates of effects on additional marijuana outcomes, of MML provisions (e.g. dispensaries) and among demographic subgroups were abstracted and summarized. Key methodological and modeling characteristics were also described. Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines were followed.

Results

None of the 11 studies found significant estimates of pre–post MML changes compared with contemporaneous changes in non‐MML states for marijuana use prevalence among adolescents. The meta‐analysis yielded a non‐significant pooled estimate (standardized mean difference) of ?0.003 (95% confidence interval = ?0.012, +0.007). Four studies compared MML with non‐MML states on pre‐MML differences and all found higher rates of past‐month marijuana use in MML states pre‐MML passage. Additional tests of specific MML provisions, of MML effects on additional marijuana outcomes and among subgroups generally yielded non‐significant results, although limited heterogeneity may warrant further study.

Conclusions

Synthesis of the current evidence does not support the hypothesis that US medical marijuana laws (MMLs) until 2014 have led to increases in adolescent marijuana use prevalence. Limited heterogeneity exists among estimates of effects of MMLs on other patterns of marijuana use, of effects within particular population subgroups and of effects of specific MML provisions.

     

Poor adherence to HIV monitoring and treatment guidelines for HIV-infected injection drug users

Objectives

There is growing concern about access to HIV/AIDS care among injection drug users (IDUs). We examined rates of CD4 cell count monitoring and correlates among HIV‐infected IDUs.

Methods

This prospective observational cohort study of 460 community‐recruited HIV‐infected IDUs was situated in a Canadian city where all medical care is provided free of charge. Over a median follow‐up period of 76 months, we evaluated factors associated with CD4 cell count monitoring through a linkage with a centralized CD4 registry.

Results

Overall, <5% of IDUs had CD4 monitoring consistent with local therapeutic guidelines. In multivariate analyses, after adjustment for being on antiretroviral therapy [odds ratio (OR) 2.21, 95% confidence interval (CI) 1.84–2.70, P<0.001] female gender (OR 0.71, 95% CI 0.57–0.89, P=0.003), non‐White ethnicity (OR 0.75, 95% CI 0.60–0.94, P=0.014), use of methadone maintenance therapy (OR 1.66, 95% CI 1.42–1.94, P<0.001) and daily heroin use (OR 0.72, 95% CI 0.61–0.85, P<0.001) were independently associated with CD4 monitoring.

Conclusions

Strategies to improve CD4 surveillance among IDUs are critically important, particularly for female and non‐White IDUs. Expanded treatment for heroin dependence appears to have the greatest potential for improved care.     

Emergency department utilization among HIV‐infected patients in a multisite multistate study*

Objective

The aim of this study was to examine Emergency Department (ED) utilization and clinical and sociodemographic correlates of ED use among HIV‐infected patients.

Methods

During 2003, 951 patients participated in face‐to‐face interviews at 14 HIV clinics in the HIV Research Network. Respondents reported the number of ED visits in the preceding 6 months. Using logistic regression, we identified factors associated with visiting the ED in the last 6 months and admission to the hospital from the ED.

Results

Thirty‐two per cent of respondents reported at least one ED visit in the last 6 months. In multivariate analysis, any ED use was associated with Medicaid insurance, high levels of pain (the third or fourth quartile), more than seven primary care visits in the last 6 months, current or former illicit drug use, social alcohol use and female gender. Of those who used ED services, 39% reported at least one admission to the hospital. Patients with pain in the highest quartile reported increased admission rates from the ED as did those who made six or seven primary care visits, or more than seven primary care visits vs. three or fewer.

Conclusions

The likelihood of visiting the ED has not diminished since the advent of highly active antiretroviral therapy (HAART). More ED visits are to treat illnesses not related to HIV or injuries than to treat direct sequelae of HIV infection. With the growing prevalence of people living with HIV infection, the numbers of HIV‐infected patients visiting the ED may increase, and ED providers need to understand potential complications produced by HIV disease.     

Attitudes towards drug legalization among drug users

Research shows that support for legalization of drugs varies significantly among different sociodemographic and political groups. Yet there is little research examining the degree of support for legalization of drugs among drug users. This paper examines how frequency and type of drug use affect the support for legalization of drugs after adjusting for the effects of political affiliation and sociodemographic characteristics. A sample of 188 drug users and non-drug users were asked whether they would support the legalization of marijuana, cocaine, and heroin. Respondents reported their use of marijuana, crack, cocaine, heroin, speedball, and/or methamphetamines during the previous 30 days. Support for legalization of drugs was analyzed by estimating three separate logistic regressions. The results showed that the support for the legalization of drugs depended on the definition of "drug user" and the type of drug. In general, however, the results showed that marijuana users were more likely to support legalizing marijuana, but they were less likely to support the legalization of cocaine and heroin. On the other hand, users of crack, cocaine, heroin, speedball, and/or methamphetamines were more likely to support legalizing all drugs including cocaine and heroin.     

Assessing the risk of marijuana use disorder among adolescents and adults who use marijuana

Background: The changing political and social climate surrounding marijuana use, coupled with the fact that available estimates of marijuana use disorder prevalence are outdated and do not adequately represent adolescents, underscore the need for up-to-date and comprehensive prevalence estimates of marijuana use disorder. Objectives: To provide recent national estimates of marijuana use disorder as a function of usage patterns, age, and other sociodemographic, substance use, and mental health variables. Methods: Analyses of data from the 2014 National Survey on Drug Use and Health examined the prevalence of marijuana use disorder among respondents (N = 55,271) with various sociodemographic, substance use, and mental health characteristics. Logistic and multinomial regression analyses examined the correlates of marijuana use disorder as a function of these variables, with a special focus on age. Results: In 2014, 3.49% of lifetime, 11.62% of past-year, and 15.32% of past-30-day marijuana users met DSM-IV criteria for a marijuana use disorder; rates among youth generally were at least double those of adults across reported time frame and intensity of use. Regression analyses indicated that young age, black race/ethnicity, greater intensity of use, current tobacco/nicotine use, and alcohol and other drug use disorders were associated with increased odds of a marijuana use disorder. Conclusions: A significant proportion of marijuana users, especially youth, are at risk for having a marijuana use disorder, even at relatively low levels of use.     

The Marijuana Check-up: reaching users who are ambivalent about change

AIMS: A brief intervention called the Marijuana Check-up (MCU) was designed to attract adult marijuana users who were experiencing adverse consequences, but who were ambivalent about change and would be unlikely to seek treatment. Our objective was to determine whether the MCU would reach the target population. DESIGN: Comparisons were made between those who enrolled in the MCU versus those who were screened but failed to follow through with enrollment on demographic, drug use and stage of change variables. Comparisons were also made between participants in the MCU and participants in a concurrently offered treatment project that targeted marijuana users who wanted to quit. SETTING: The study took place at the University of Washington in Seattle. PARTICIPANTS: Participants were adult marijuana users who telephoned and expressed interest in the MCU (n = 587). MEASUREMENT: Study variables included stage of change, frequency and duration of drug use, DSM-IV cannabis dependence and abuse diagnoses and negative consequences of marijuana use assessed via interviews and questionnaires. FINDINGS: Callers to the MCU were near-daily marijuana users, two-thirds of whom were in the pre-contemplation or contemplation stage of change. Participants who enrolled in the MCU reported fewer problems related to marijuana use and less readiness to make changes compared to those enrolled in the treatment study, despite similar levels of drug use. CONCLUSIONS: The MCU attracted and enrolled near-daily users of marijuana who experienced negative consequences but were ambivalent about making changes. The MCU potentially has a role in the continuum of care for substance abuse problems.     

A flicker paradigm for inducing change blindness reveals alcohol and cannabis information processing biases in social users

Aim To apply a new paradigm using transient changes to visual scenes to explore information processing biases relating to ‘social’ levels of alcohol and cannabis use. Participants Male and female student volunteers (n = 200) not self‐reporting substance‐related problems. Setting Quiet testing areas throughout the university campus. Design A flicker paradigm, for inducing change blindness with lighter and heavier social users of alcohol (experiment 1, n= 100) and social users and non‐users of cannabis (experiment 2, n= 100), explored the associations between habitual level of use and the latency to detection of a single substance‐related or neutral change made to a scene of grouped substance‐related and neutral objects. Measurements Alcohol use was measured as the number of units of the heaviest drinking day from the previous week; cannabis use as the number of months of use in previous 12. Change–detection latency comparisons were used to evaluate processing biases. Findings In both experiments, (i) heavier social users detected substance‐related changes quicker than lighter and non‐users; (ii) lighter and non‐users detected substance‐neutral changes quicker than heavier users; (iii) heavier social users detected substance‐related quicker than substance‐neutral changes; and (iv) lighter and non‐users detected substance‐neutral changes quicker than substance‐related changes. Conclusions Alcohol and cannabis processing biases are found at levels of social use, have the potential to influence future consumption and for this reason merit further research.     

Quantifying the impact of transient joint symptoms,chronic joint symptoms,and arthritis: A population‐based approach

Objective

To estimate the prevalence and co‐occurrence of self‐reported doctor‐diagnosed arthritis, chronic joint symptoms (pain, aching, stiffness, or swelling on most days for a month), and transient joint symptoms (pain, aching, stiffness, or swelling but not on most days for a month), and to compare the sociodemographic characteristics, activity limitations, and health‐related quality of life (HRQOL) of people with joint conditions with those who have no self‐reported doctor‐diagnosed arthritis and no joint symptoms.

Methods

Data from the 2004 population‐based South Australian Health Omnibus Survey (n = 2,840, ages 18–96 years) were used in the study. Activity limitations were assessed using 10 activity limitations questions from the Short Form 36 health survey. HRQOL was assessed using the Assessment of Quality of Life scale.

Results

Half of all respondents reported having joint problems, with 26%, 11%, and 13% reporting self‐reported doctor‐diagnosed arthritis, chronic joint symptoms, and transient joint symptoms, respectively. Chronic joint conditions (self‐reported doctor‐diagnosed arthritis and chronic joint symptoms) accounted for 74% of all joint problems and were associated with higher odds of activity limitations and poorer HRQOL. The frequency of transient and chronic joint symptoms was highest among middle‐aged participants (ages 45–54 years for transient and 45–64 years for chronic joint symptoms) and those who had a body mass index in the obese range. Prevalence of self‐reported doctor‐diagnosed arthritis increased with age and was higher among women and those who were overweight or obese.

Conclusion

This study documented the high prevalence and impact of joint conditions in the community. Chronic joint conditions affect daily life and are substantial barriers for effective public health interventions aimed at reducing obesity and inactivity.     

Flashblood: blood sharing among female injecting drug users in Tanzania

Aims This study examined the association between the blood‐sharing practice of ‘flashblood’ use and demographic factors, human immunodeficiency virus (HIV) status and variables associated with risky sex and drug behaviors among female injecting drug users. Flashblood is a syringe‐full of blood passed from someone who has just injected heroin to someone else who injects it in lieu of heroin. Design A cross‐sectional study. Setting Dar es Salaam, Tanzania. Participants One hundred and sixty‐nine female injecting drug users (IDUs) were recruited using purposive sampling for hard‐to‐reach populations. Measurements The association between flashblood use, demographic and personal characteristics and risky sex and drug use variables was analyzed by t‐test and χ² test. The association between flashblood use and residential neighborhood was mapped. Findings Flashblood users were more likely to: be married (P = 0.05), have lived in the current housing situation for a shorter time (P < 0.000), have been forced as a child to have sex by a family member (P = 0.007), inject heroin more in the last 30 days (P = 0.005), smoke marijuana at an earlier age (P = 0.04), use contaminated rinse‐water (P < 0.03), pool money for drugs (P < 0.03) and share drugs (P = 0.000). Non‐flashblood users were more likely to live with their parents (P = 0.003). Neighborhood flashblood use was highest near downtown and in the next two adjoining suburbs and lowest in the most distant suburbs. Conclusions These data indicate that more vulnerable women who are heavy users and living in shorter‐term housing are injecting flashblood. The practice of flashblood appears to be spreading from the inner city to the suburbs.     

Cocaine Dependence and Concurrent Marijuana Use: A Comparison of Clinical Characteristics

Background/Objectives: Marijuana is the most commonly used illicit substance, yet among the least studied in medication development research. Cocaine-dependent individuals frequently also use marijuana; however, little is known about the effect of this combined use on treatment presentation. Methods: Marijuana use was assessed in 1183 individuals seeking outpatient treatment for cocaine dependence. Based on past 30 days of use, the sample was divided into three groups: () patients reporting no recent marijuana use (n = 634); () occasional use (n = 403); () and frequent concurrent marijuana use (n = 146). Differences on baseline measures of substance use, addiction severity (ASI), psychopathology, and sociodemographic characteristics were examined as a function of level of marijuana use. Results: Frequent marijuana users were more likely to be female, Caucasian, and younger than other groups. Cocaine-dependent patients with frequent marijuana use also used more cocaine and alcohol, and reported more medical, legal, and psychiatric problems, including antisocial personality disorder. Conclusion and Scientific Significance: Cocaine-dependent patients with frequent marijuana use present for treatment with more severe impairment. Accounting for this heterogeneity among participants may improve treatment outcome.     

Collaborative behavioral management among parolees: drug use, crime and re-arrest in the Step'n Out randomized trial

Aims To determine whether collaborative behavioral management (CBM) reduces substance use, crime and re‐arrest among drug‐involved parolees. Design Step'n Out was a randomized behavioral trial of CBM versus standard parole (SP) during 2004–08. CBM adapted evidence‐based role induction, behavioral contracting and contingent reinforcement to provide parole officer/treatment counselor dyads with positive tools in addition to sanctions to manage parolees' behavior over 12 weeks. Setting Six parole offices in five states in the USA. Participants Parolee volunteers with a mandate for addiction treatment and a minimum of 3 months of parole (n = 476). Follow‐up was 94% at 3 months and 86% at 9 months. Measurements Drug use and crime in a given month from calendar interviews 3 and 9 months after parole initiation, and re‐arrests from criminal justice administrative data. Findings The CBM group had fewer months in which they used their primary drug [adjusted risk ratio (ARR) 0.20, 95% confidence interval (CI): 0.05, 0.78, P = 0.02] and alcohol (ARR 0.38, 95% CI: 0.22, 0.66, P = 0.006) over follow‐up. CBM had its greatest effects among parolees who reported marijuana or another ‘non‐hard’ drug as their primary drug; parolees who preferred stimulants or opiates did not benefit. No differences were seen in total crime, re‐arrests or parole revocations. Conclusions Collaborative behavioral management may reduce substance use among primary marijuana or other ‘non‐hard’ drug‐using parolees without increasing revocations. Because the majority of drug violation arrests in the United States are for marijuana, these findings have important implications for the management of a substantial proportion of the US community correctional population.     

Longitudinal associations between outpatient medical care use and substance use among rural stimulant users

Background: Negative views toward substance use treatment among some rural substance users and limited treatment resources in rural areas likely affect substance use utilization. It is therefore important to determine whether accessing healthcare options other than substance use treatment, specifically outpatient medical care (OMC), is associated with reductions in substance use. Objectives: We examined whether use of OMC was associated with reductions in substance use among rural substance users over a three-year period. We also explored whether substance user characteristics, including substance-use severity and related-problems, moderated this potential relationship. Methods: Data were collected from an observational study of 710 (61% male) stimulant users using respondent-driven sampling. Participants were recruited from rural counties of Arkansas, Kentucky, and Ohio. Results: We found a significant main effect of having at least one OMC visit (relative to none) on fewer days of alcohol, crack cocaine, and methamphetamine use over time. Fewer days of alcohol, crack cocaine, and methamphetamine use were reported in participants with at least one OMC visit (relative to those with none) among those reporting higher Addiction Severity Index employment and psychiatric severity scores, and low education, respectively. Conclusion: Our findings extend the results from prior studies with urban substance users to show that contact with an outpatient medical care clinic is associated with reductions in substance use over time among rural substance users with especially poorer functioning. These findings highlight the potential importance of OMCs in addressing unhealthy substance use in rural communities.     

Factors associated with injection cessation, relapse and initiation in a community-based cohort of injection drug users in Chennai, India

Aims To characterize factors associated with injection cessation, relapse and initiation. Design The Madras Injection Drug User and AIDS Cohort Study (MIDACS) is a prospective cohort of injection drug users (IDUs) recruited in 2005–06 with semi‐annual follow‐up to 2009. Discrete‐time survival models were used to characterize predictors of time to first injection cessation and relapse. Setting Chennai, India. Participants A total of 855 IDUs who reported injecting in the 6 months prior to baseline and had >1 follow‐up visit. Measurements Cessation was defined as the first visit where no injection drug use was reported (prior 6 months) and relapse as the first visit where drug injection (prior 6 months) was reported after first cessation. Findings All participants were male; median age was 35 years. Over 3 years, 92.7% reported cessation [incidence rate (IR): 117 per 100 person‐years]. Factors associated positively with cessation included daily injection and incarceration and factors associated negatively with cessation included marriage, alcohol and homelessness. Of those who reported cessation, 23.6% relapsed (IR: 19.7 per 100 person‐years). Factors associated positively with relapse included any education, injection in the month prior to baseline, sex with a casual partner, non‐injection drug use, incarceration and homelessness. Alcohol was associated negatively with relapse. The primary reasons for cessation were medical conditions (37%) and family pressure (22%). The majority initiated with non‐injection drugs, transitioning to injection after a median 4 years. Conclusions Injection drug users in southern India demonstrate a high rate of injection cessation over 3 years, but relapse is not uncommon. Compensatory increases in alcohol use indicate that cessation of injection does not mean cessation of all substance use. Family pressure, concerns about general health, fear of human immunodeficiency virus infection and a history of non‐injection drug use are important correlates of cessation.     

Marijuana Use and Renal Function Among US Adults

Background

In recent years, the number of states that have legalized medical marijuana or retail sales has increased, bringing potential changes of marijuana use pattern among the general population. However, health effects of acute and chronic marijuana use on many relevant health outcomes, including renal function, remain largely unexamined. In this study, we aimed to assess the association between recent and past marijuana use and renal function.