Despite the growing prevalence of illicit stimulant drug use internationally, and the widespread involvement of people who inject drugs (IDU) within street-based drug markets, little is known about the impact of different types of street-based income generation activities on the cessation of stimulant use among IDU.
Data were derived from an open prospective cohort of IDU in Vancouver, Canada. We used Kaplan-Meier methods and Cox proportional hazards regression to examine the effect of different types of street-based income generation activities (e.g., sex work, drug dealing, and scavenging) on time to cessation of stimulant use.
Between December, 2005 and November, 2012, 887 IDU who use stimulant drugs (cocaine, crack cocaine, or crystal methamphetamine) were prospectively followed-up for a median duration of 47 months. In Kaplan-Meier analyses, compared to those who did not engage in street-based income generation activities, participants who reported sex work, drug dealing, scavenging, or more than one of these activities were significantly less likely to report stimulant drug use cessation (all p<0.001). When considered as time-updated variables and adjusted for potential confounders in a multivariable model, each type of street-based income generation activity remained significantly associated with a slower time to stimulant drug cessation (all p<0.005).
Our findings highlight the urgent need for strategies to address stimulant dependence, including novel pharmacotherapies. Also important, structural interventions, such as low-threshold employment opportunities, availability of supportive housing, legal reforms regarding drug use, and evidence-based approaches that reduce harm among IDU are urgently required.
people who inject drugs; stimulants; crack cocaine; crystal methamphetamine; drug cessation; street economy
The need for comprehensive analysis to compare and combine data across multiple studies in order to validate and extend results is widely recognized. This paper aims to assess the extent of data compatibility in the substance abuse and addiction (SAA) sciences through an examination of measure commonality, defined as the use of similar measures, across grants funded by the National Institute on Drug Abuse (NIDA) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Data were extracted from applications of funded, active grants involving human-subjects research in four scientific areas (epidemiology, prevention, services, and treatment) and six frequently assessed scientific domains. A total of 548 distinct measures were cited across 141 randomly sampled applications. Commonality, as assessed by density (range of 0–1) of shared measurement, was examined. Results showed that commonality was low and varied by domain/area. Commonality was most prominent for (1) diagnostic interviews (structured and semi-structured) for substance use disorders and psychopathology (density of 0.88), followed by (2) scales to assess dimensions of substance use problems and disorders (0.70), (3) scales to assess dimensions of affect and psychopathology (0.69), (4) measures of substance use quantity and frequency (0.62), (5) measures of personality traits (0.40), and (6) assessments of cognitive/neurologic ability (0.22). The areas of prevention (density of 0.41) and treatment (0.42) had greater commonality than epidemiology (0.36) and services (0.32). To address the lack of measure commonality, NIDA and its scientific partners recommend and provide common measures for SAA researchers within the PhenX Toolkit.
Measure commonality; data harmonization; standard measures; gene-environment interactions; substance use; abuse; addiction
Marijuana and tobacco are the substances used most commonly by adolescents and co-occurring use is common. Use of one substance may potentiate the addictive properties of the other. The current study examined the severity of nicotine addiction among teen smokers as a function of co-occurring marijuana use.
Participants were 165 adolescents (13–17 years old) who reported smoking at least 1 cigarette per day (CPD) in the past 30 days. General linear models examined the association of marijuana use with multiple measures of nicotine addiction including the Modified Fagerström Tolerance Questionnaire (mFTQ), Hooked on Nicotine Checklist (HONC), ICD-10, and the Nicotine Dependence Syndrome Scale (NDSS).
The adolescent sample (mean age=16.1 years, SD=0.95) averaged 3.0 CPD (SD=3.0) for 1.98 years (SD=1.5). Most (79.5%) also smoked marijuana in the past 30 days. In models controlling for age, daily smoking status, and years of tobacco smoking, frequency of marijuana use accounted for 25–44% of the variance for all four measures of adolescent nicotine dependence.
Marijuana use was associated with greater reported nicotine addiction among adolescent smokers. The findings suggest a role of marijuana in potentiating nicotine addiction and underscore the need for treatments that address both smoked substances.
adolescent; marijuana; cannabis; tobacco; nicotine addiction
A core vulnerability trait for substance use disorder (SUD) is behavioral disinhibition. Error processing is a central aspect of inhibitory control that determines adaptive adjustment of performance; yet it is a largely overlooked aspect of disinhibition as it relates to risk for SUD. We investigated whether differences in brain activation during both successful and failed inhibition predicts early problem substance use.
Forty-five 9–12 year olds underwent a functional MRI scan during a go/no-go task. They were then followed over approximately 4 years, completing assessments of substance use. Externalizing behavior was measured at ages 3–8, 9–12 and 11–13. Participants with drug use or problem alcohol use by ages 13–16 (n=13; problem-user group) were individually matched by gender, age, and family history of alcoholism with non-substance-using children (n=13; non-user group). The remaining 19 participants provided an independent sample from which to generate unbiased regions-of-interest for hypothesis testing in the problem-user and non-user groups.
No differences were observed between groups in activation during correct inhibition compared with baseline. A significant difference arose in left middle frontal gyrus (LMFG) activation during failed inhibition compared with correct inhibition, with the problem-user group demonstrating blunted activation. The problem-user group also had more externalizing problems at ages 11–13. Logistic regression found that activation of LMFG significantly predicted group membership over and above externalizing problems.
Blunted LMFG activation during performance errors may underlie problems adapting behavior appropriately, leading to undercontrolled behavior, early problem substance use and increased risk for SUD.
inhibitory control; error monitoring; vulnerability; substance abuse; development
Drinking alcohol before sex increases the likelihood of engaging in sexual risk behaviors and risk for HIV infection. Relationship status (single versus partnered) and alcohol use disorders (AUD) are associated with each other and sexual risk behaviors, yet have not been examined as predictors of drinking alcohol before sex, using national data. This study examined whether relationship status and AUD increased the likelihood of regularly drinking alcohol before sex in a nationally representative sample.
The main and additive interaction effects of relationship status and AUD on regularly drinking alcohol before sex were analyzed among sexually active drinkers (N=17,491) from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). Regularly drinking alcohol before sex was defined as drinking alcohol most or all of the time before sex.
After adjustment for controls, relationship status (AOR=3.51; CI=2.59–4.75) and AUD (AOR=6.24; CI=5.16–7.53) increased the likelihood of regularly drinking alcohol before sex and interacted to differentially increase this risk, with the effect of being single on the likelihood of regularly drinking alcohol before sex increased among participants with AUD (p<.001).
This study reinforces the importance of relationship status and AUD to the risk for regularly drinking alcohol before sex. Public health efforts should target alcohol and HIV prevention messages to single adults, particularly those with AUD, highlighting their risk for regularly drinking alcohol before sex.
drinking alcohol before sex; sexual risk behaviors; alcohol use disorders; relationship status; NESARC
Use of synthetic cathinones (SC) and cannabimimetics (i.e., “THC homologues” [TH]) is associated with adverse health effects. We investigated the epidemiology of synthetic drug use among a cohort of injection drug users (IDUs) in San Diego, California.
We used logistic regression analysis to identify correlates of SC and TH use among 485 IDUs enrolled from June 2012 to September 2013.
Seven percent of participants reported ever using SC and 30% reported ever using TH. In multivariate logistic regression, age and recent hospitalization were significantly associated with odds of SC use (Adjusted Odds Ratio [AOR] 0.93, 95% Confidence Interval [C.I.] 0.90, 0.97; and AOR 2.34 95% C.I. 1.00, 5.49, respectively) and TH use (AOR 0.96, 95% C.I. 0.94, 0.98; and AOR 2.62, 95% C.I. 1.47, 4.68, respectively). Use of methamphetamine (AOR 9.35, 95% C.I. 1.20, 72.79) and club drugs in the past six months (AOR 3.38, 95% C.I. 1.17, 9.76) were significantly associated with SC use. Being on probation/parole (AOR 2.42, 95% C.I. 1.44,4.07), initiating injection drug use with stimulants (AOR 1.89 95% C.I. 1.13, 3.16), and past six-month marijuana (AOR 9.22, 95% C.I. 4.49, 18.96) and prescription drug use (AOR 1.98, 95% C.I. 1.20, 3.27) were significantly associated with TH use.
A considerable proportion of IDU use synthetic drugs and may experience harms associated with their use. Findings have implications for criminal justice system management. Prevention efforts should emphasize the risks associated with rapidly changing synthetic formulations, and the potential harms associated with polydrug use.
synthetic drugs; cathinones; cannabimimetics; injection drug use
For the DSM-5-defined alcohol use disorder (AUD) diagnosis, a tricategorized scale that designates mild, moderate, and severe AUD was selected over a fully dimensional scale to represent AUD severity. The purpose of this study was to test whether the DSM-5-defined AUD severity measure was as proficient a predictor of alcohol use following a brief intervention, compared to a fully dimensional scale.
Heavy drinking primary care patients (N=246) received a physician-delivered brief intervention (BI), and then reported daily alcohol consumption for six months using an Interactive Voice Response (IVR) system. The dimensional AUD measure we constructed was a summation of all AUD criteria met at baseline (mean = 6.5; SD = 2.5). A multi-model inference technique was used to determine whether the DSM-5 tri-categorized severity measure or a dimensional approach would provide a more precise prediction of change in weekly alcohol consumption following a BI.
The Akaike information criterion (AIC) for the dimensional AUD model (AIC=7623.88) was four points lower than the tri-categorized model (AIC=7627.88) and weight of evidence calculations indicated there was 88% likelihood the dimensional model was the better approximating model. The dimensional model significantly predicted change in alcohol consumption (p =.04) whereas the DSM-5 tri-categorized model did not.
A dimensional AUD measure was superior, detecting treatment effects that were not apparent with tri-categorized severity model as defined by the DSM-5. We recommend using a dimensional measure for determining AUD severity.
DSM-5; diagnosis; alcohol use disorder severity; dimensional; alcohol use disorder; multi-model inference
Concurrent administration of dopamine and serotonin reuptake inhibitors reduces cocaine self-administration in monkeys. Consonant with this, clinical trials assessing modafinil and selective serotonin reuptake inhibitors alone show some efficacy as potential pharmacotherapies for cocaine dependence. We hypothesized that combining modafinil with escitalopram would attenuate the euphoric effects of cocaine to a greater degree than modafinil alone.
In a randomized, double blind, parallel groups design participants received either placebo (0 mg/day; n = 16), modafinil (200 mg/day; n = 16), escitalopram (20 mg/day; n = 17), or modafinil+escitalopram (200+20 mg/day; n = 15) for 5 days. On day 5, during separate sessions participants received an intravenous sample of cocaine (0 or 20mg; randomized) and five $1 bills. Participants rated the subjective effects of the infusions and subsequently made choices to either return $1 and receive another infusion or keep $1 and receive no infusion.
Compared to saline, cocaine (20mg) significantly (p ≤ 0.008) increased most ratings, including “Good Effects”, “Stimulated”, and “High”. Relative to placebo, modafinil significantly (p ≤ 0.007) attenuated subject-rated increases of “Any Drug Effect”, “High”, “Good Effects”, and “Stimulated” produced by cocaine. Compared to saline, participants chose cocaine infusions significantly more; however, no treatment significantly reduced choices for cocaine infusions. Escitalopram did not enhance the efficacy of modafinil to reduce any measure.
Modafinil attenuated many positive subjective effects produced by cocaine; however, escitalopram combined with modafinil did not enhance the efficacy of modafinil to reduce cocaine effects.
Cocaine; Modafinil; Escitalopram; Subjective Effects
Young men who have sex with men (YMSM) are substantially more likely to use
illicit drugs and other substances compared to their heterosexual peers. Substance use
during adolescence has critical implications for long-term physical and mental health,
and among YMSM may lead to HIV infection. The goal of the current study was to describe
lifetime and past six month prevalence and patterns of substance use across multiple
substances in a community sample of racially-diverse YMSM.
Participants were 450 YMSM aged 16–20 living in Chicago and surrounding
areas who were recruited beginning December, 2009 using a modified form of respondent
driven sampling. Analyses were conducted with multivariate logistic regression and
latent class analysis (LCA).
Prevalence of substance use was high in this sample of majority racial minority
YMSM, and only 17.6% reported no substance use during the past six months. Black
YMSM had lower prevalence of use of all substances except marijuana compared to White
YMSM, while Latino YMSM had lower prevalence of alcohol, marijuana, and club drug use.
Bisexual YMSM reported higher prevalence of cigarette smoking, stimulant use, and club
drug use compared to gay/mostly gay YMSM but lower numbers of bisexual participants
limited the ability to detect statistically significant differences. LCA found that YMSM
fell into three general categories of substance users: alcohol and marijuana users,
polysubstance users, and low marijuana users.
Analyses reveal important group differences in prevalence and patterns of
substance use in YMSM that have important implications for intervention.
young men who have sex with men; substance use; alcohol; cigarette smoking
Given numerous reports implicating involvement of the precuneus in cue-reactivity paradigms, the goal of this investigation was to examine the relationship between activation of the precuneus in response to drug cues and measures of subjective craving and severity of dependence in volunteers who were comorbid for alcohol and nicotine abuse.
Forty research participants, who all reported heavy drinking and daily smoking, were recruited (15 women; 70% Caucasian; mean age = 31.2 years) for a functional magnetic resonance imaging (fMRI) session involving a cigarette video-cues task and an alcohol taste-cues task. Mean precuneus activation from both tasks during cue presentation was subjected to bivariate correlation analyses with indices of dependence severity and subjective craving.
Precuneus activation in the contrast of Cigarette Cues vs. Control Cues was positively correlated with scores on the Fagerström Test of Nicotine Dependence (r=0.389, p=0.016), and activation in the Alcohol Cues vs. Control Cues contrast was positively correlated with Alcohol Dependence Scale scores (r=0.338, p=0.038). No correlations with subjective craving were observed (ps>0.05).
These findings indicate that the precuneus is involved in cue reactivity for both cigarettes and alcohol, and that this involvement is moderated by severity of drug dependence. The precuneus may be a cortical locus for neuroplastic changes related to drug dependence.
precuneus; cigarettes; alcohol use disorder; fMRI; cue-reactivity; craving
Nicotine dependence plays a critical role in addiction to tobacco products, and thus contributes to a variety of devastating tobacco-related diseases (SGR 2014). Annual costs associated with smoking in the US are estimated to be between $289 and $333 billion. Effective interventions for nicotine dependence, especially in smokers, are a critical barrier to the eradication of tobacco-related diseases. This overview highlights research presented at the Plenary Symposium of Behavior, Biology and Chemistry: Translational Research in Addiction Conference (BBC), hosted by the UT Health Science Center San Antonio, on March 9–10, 2013. The Plenary Symposium focused on tobacco addiction, and covered topics ranging from basic science to national policy. As in previous years, the meeting brought together globally-renowned scientists, graduate student recruits, and young scientists from underrepresented populations in Texas and other states with the goal of fostering interest in drug addiction research in young generations.
Nicotine withdrawal; Nicotinic receptor antagonists; Nicotine dependence; Smoking cessation; Relapse; Nicotine analogs; Nicotine vaccine; Low nicotine content cigarettes; CHRNA5; Medial Habenula; Interpeduncular Nucleus; Tobacco product regulation
Adult alcohol consumption is influenced by peer consumption, but whether peer drinking is associated with first-onset alcohol dependence (AD) in adults after age 30 is unknown.
703 adult participants in the St. Louis Epidemiologic Catchment Area Survey (ECA) with no prior history of AD, but with high risk based on previously reported drinking or family history, were re-interviewed 11 years after the last ECA assessment to detect new cases of AD (age at follow-up: M(S.D.) = 42.9 (8.2)). Incident AD during the assessment interval was examined in relation to drinking patterns in the social network and history of alcohol problems in parents.
Fifteen percent of the sample had a first-onset of AD; another 19.5% never developed AD but were high-risk drinkers at follow-up. Of those who developed AD, 32.1% were remitted and 67.9% were unremitted (current AD) or unstably remitted (asymptomatic high-risk drinkers). Compared to abstinent or low-risk drinkers who did not develop AD, high-risk drinkers with no AD and unremitted/unstably remitted individuals were 4 times as likely to report moderate drinkers in their networks and remitted individuals were nearly 3 times as likely to report network members in recovery from alcohol problems. Associations of social network drinking with remitted and current AD were similar in strength to those of parental alcohol problems.
Social network drinking patterns are associated with high-risk drinking and with the development of incident AD in adults, with effects equal to that of alcohol problems in both parents.
social network; adult onset; alcohol use disorder; alcohol dependence
This study sought to examine the utility of hair testing as a research measure of drug use among individuals with moderate-risk drug use based on the internationally-validated Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST).
This study is a secondary analysis using baseline data from a randomized trial of brief intervention for drug misuse, in which 360 adults with moderate-risk drug use were recruited from two community clinics in New Mexico, USA. The current study compared self-reported drug use on the ASSIST with laboratory analysis of hair samples using a standard commercially-available 5-panel test with assay screening and gas chromatography/mass spectrometry (GC/MS) confirmation. Both self-report and hair testing covered a 3 month period.
Overall concordance between hair testing and self-report was 57.5% (marijuana), 86.5% (cocaine), 85.8% (amphetamines), and 74.3% (opioids). Specificity of hair testing at standard laboratory cut-offs exceeded 90% for all drugs, but sensitivity of hair testing relative to self-report was low, identifying only 52.3% (127/243) of self-disclosed marijuana users, 65.2% (30/46) of cocaine users, 24.2% (8/33) of amphetamine users, and 2.9% (2/68) of opioid users. Among participants who disclosed using marijuana or cocaine in the past 3 months, participants with a negative hair test tended to report lower-frequency use of those drugs (p< .001 for marijuana and cocaine).
Hair testing can be useful in studies with moderate-risk drug users, but the potential for under-identification of low-frequency use suggests that researchers should consider employing low detection cut-offs and using hair testing in conjunction with self-report.
Hair testing; self-report; moderate-risk drug use; brief intervention; primary care
Social learning models of substance use propose that drug-use behaviors are learned by observing and mimicking the behavior of others. The aim of this study was to examine the acquisition of cocaine self-administration in three groups of experimentally naïve rats: rats that were tested in isolation, rats that were tested in the presence of another rat that had access to cocaine and had previously been trained to self-administer cocaine, and rats that were tested in the presence of another rat that did not have access to cocaine.
Male rats were reared in isolated or pair-housed conditions and implanted with intravenous catheters. Pair-housed rats were then assigned to drug-experienced or drug-naïve conditions. In the drug-experienced condition, one rat of each pair was trained to self-administer cocaine in isolation before the reintroduction of its partner. In the drug-naïve condition, one rat of each pair did not have access to cocaine for the duration of the study. For each group, the acquisition of cocaine self-administration was measured over 15 days in rats with access to cocaine but no prior operant training.
Rats tested with a drug-experienced partner were faster to acquire cocaine self-administration and emitted more active lever presses than rats tested with a cocaine-naïve partner. Data for the isolated control group fell between the other two groups on these measures.
These data indicate that the acquisition of cocaine self-administration can either be facilitated or inhibited by social contact. Collectively, these results support a social-learning model of substance use.
cocaine; rat; self-administration; social; social learning
Maternal smoking during pregnancy is correlated with increased substance use in offspring. Research using rodent models shows that gestational nicotine exposure produces enduring alterations in the neurodevelopment of motivational systems, and that rats prenatally treated with nicotine have altered motivation for drug reinforcement on fixed-ratio (FR) schedules of reinforcement. Objective: The present study investigated methamphetamine (METH) self-administration in adult offspring prenatally exposed to intravenous (IV) nicotine or saline using a progressive-ratio (PR) schedule of reinforcement.
Pregnant rats were administered IV prenatal saline (PS) or nicotine (PN; 0.05 mg/kg/infusion), 3x/day during gestational days 8–21. At postnatal day 70, offspring acquired a lever-press response for sucrose (26%, w/v; FR1-3). Rats were trained with METH (0.05 mg/kg/infusion), and following stable FR responding, animals were tested using a progressive-ratio (PR) schedule for three different doses of METH (0.005, 0.025, and 0.05 mg/kg/infusion).
METH infusion, active lever presses, and the ratio breakpoint are reported. PN-exposed animals exhibited more METH-maintained responding than PS controls, according to a dose × prenatal treatment interaction (e.g., infusions). PN rats self-administered more METH infusions between the range of 0.025 and 0.05, but not for the 0.005 mg/kg/infusion dose.
IV PN-exposure produced enhanced motivation to self-administer METH. These findings indicate that pregnant women who smoke tobacco may impart neurobiological changes in offspring’s motivational systems that render them increasingly vulnerable to drug abuse during adulthood.
methamphetamine; prenatal; nicotine; rat; self-administration; motivation
Parental divorce and psychopathology are well-documented risk factors for alcohol use disorders (AUD) in the United States and other countries where divorce is common and per capita total alcohol consumption is moderate to high. However, little is known about these relationships in countries where divorce and alcohol problems are less common, such as Israel.
Israeli adult household residents (N=797) age 21–45 were interviewed in person between 2007 and 2009. Logistic regression models were used to examine main and additive interaction effects of parental divorce and psychopathology on lifetime DSM-IV AUD, adjusting for age, gender, and ethnicity.
Parental divorce (OR=2.18, p≤.001) and parental psychopathology (OR=1.61, p≤.01) were independently associated with lifetime AUD and, when considered together, showed significant interaction (p=.026). Specifically, the effect of divorce on AUD was only significant among those who also reported parental psychopathology.
This is the first study showing the influence of parental divorce and psychopathology on risk for AUD among Israeli adults, where both divorce and AUD are less common than in the United States. Alcohol prevention and treatment professionals should recognize that children who experience parental divorce and/or psychopathology could be more vulnerable to later developing AUD than those whose parents remain together and without psychopathology.
alcohol use disorders; parental divorce; parental psychopathology; Israel
Few studies examine the helpfulness and effectiveness of substance abuse treatment from the clients’ perspective.
The current secondary analysis examined the perceived helpfulness of substance abuse treatment components and its relationship to treatment outcomes among 387 Black and White adults participating in a multisite randomized clinical trial (RCT) of Motivational Enhancement Therapy. Throughout the 16-week RCT, participants self-reported substance use. Upon completion of treatment, participants completed a self-report measure assessing the perceived helpfulness of treatment components.
Black participants rated 9 out of 12 treatment components (e.g., “learning skills that will help me cope with my problems”) as being more helpful than their White counterparts, even after controlling for age, gender, employment status, primary drug type, and treatment assignment. However, perceived helpfulness ratings were not associated with substance use outcomes among Black or White participants.
Clients’ perceived helpfulness of treatment components is an important factor to consider in improving the delivery of substance abuse treatment, especially for Black adults.
perceived helpfulness; substance abuse treatment; race
•E-cigarette (EC) and nicotine replacement therapy (NRT) are used for harm reduction.•But little comparative data on their long-term use in smokers and quitters exist.•We find that long-term EC users have stronger smoker identities than NRT users.•EC users rate their product more highly and have lower intentions to stop use.•In long-term quitters, withdrawal symptoms are reduced in EC compared with NRT user.
Electronic cigarettes (ECs) and nicotine replacement therapy (NRT) are non-combustible nicotine delivery devices being widely used as a partial or a complete long-term substitute for smoking. Little is known about the characteristics of long-term users, their smoking behaviour, attachment to smoking, experience of nicotine withdrawal symptoms, or their views on these devices. This study aimed to provide preliminary evidence on this and compare users of the different products.
UK participants were recruited from four naturally occurring groups of long-term (≥6 months) users of either EC or NRT who had stopped or continued to smoke (N = 36 per group, total N = 144). Participants completed a questionnaire assessing socio-demographic and smoking characteristics, nicotine withdrawal symptoms, smoker identity and attitudes towards the products they were using.
Adjusting for relevant confounders, EC use was associated with a stronger smoker identity (Wald X2(1) = 3.9, p = 0.048) and greater product endorsement (Wald X2(1) = 4.6, p = 0.024) than NRT use, irrespective of smoking status. Among ex-smokers, EC users reported less severe mood and physical symptoms (Wald X2(1) = 6.1, p = 0.014) and cravings (Wald X2(1) = 8.5, p = 0.003), higher perceived helpfulness of the product (Wald X2(1) = 4.8, p = 0.028) and lower intentions to stop using the product (Wald X2(1) = 17.6, p < 0.001) than NRT users.
Compared with people who use NRT for at least 6 months, those who use EC over that time period appear to have a stronger smoker identity and like their products more. Among long-term users who have stopped smoking, ECs are perceived as more helpful than NRT, appear more effective in controlling withdrawal symptoms and continued use may be more likely.
NRT use; Electronic cigarettes; Harm reduction; Identity; Smoking cessation; Nicotine withdrawal
Women exhibit an accelerated progression from first cannabis use to cannabis use disorder (CUD) and show pronounced negative clinical issues related to CUD relative to men. Whether sex-dependent differences in cannabis’ direct effects contribute to the heightened risk in women is unknown. This analysis directly compared cannabis’ abuse-related subjective effects in men and women matched for current cannabis use.
Data from four double-blind, within-subject studies measuring the effects of active cannabis (3.27–5.50% THC, depending on study) relative to inactive cannabis (0.00% THC) were combined for this analysis. Data from equal numbers of men and women from each study matched for current cannabis use were pooled (total n = 35 men; 35 women); cannabis’ effects were analyzed according to cannabis condition (active versus inactive) and sex.
Active cannabis produced more robust subjective effects associated with abuse liability (‘Good,’ ‘Liking,’ ‘Take Again’) and intoxication (‘High,’ ‘Stimulated’) relative to inactive cannabis (p • 0.0001). Women reported higher ratings of abuse-related effects [‘Take Again’ and ‘Good’ (p • 0.05)] relative to men under active cannabis conditions but did not differ in ratings of intoxication. Active cannabis increased heart rate (p • 0.0001) equally for both sexes.
The results from this study suggest that when matched for cannabis use, women are more sensitive to the subjective effects related to cannabis’ abuse liability relative to men, which may contribute to the enhanced vulnerability to developing CUD. Thus, sex is an important variable to consider when assessing the development of CUD.
Cannabinoids; Abuse liability; Sex-differences; Subjective effects
Research has indicated associations between risky alcohol consumption and sexual risk behavior, which may in turn present risk of HIV acquisition or transmission. Little is known about social determinants of problematic alcohol use among African American MSM (AA MSM), a risk group disproportionately affected by HIV. The present study sought to explore associations between risky alcohol use and perceived peer norms of alcohol use among a sample of urban African American men who have sex with men (AA MSM).
A cross-sectional survey was administered to 142 AA MSM in Baltimore, Maryland, recruited using active and passive methods. Risky and hazardous alcohol use was assessed using the Alcohol Use Disorders Identification Test (AUDIT) and participants self-reported descriptive and injunctive peer norms regarding frequency and quantity of alcohol consumption.
Nearly half reported hazardous or high risk consumption of alcohol. Perceived peer alcohol norms, both descriptive and injunctive, were associated with alcohol use, including hazardous use.
The findings highlight the role of social factors on problematic alcohol use among AA MSM. Results indicate that AA MSM's use of alcohol is associated with their perceptions of peer alcohol use. Potential interventions could include norms-based campaigns that seek to reduce risky alcohol consumption among AA MSM as well as programs to screen and identify individuals with problematic alcohol use.
African American men who have sex with men; social norms; alcohol use; AUDIT
In the multi-site Prescription Opioid Addiction Treatment Study (POATS), conducted within the National Drug Abuse Clinical Trials Network, participants randomly assigned to receive individual drug counseling in addition to buprenorphine-naloxone and medical management did not have superior opioid use outcomes. However, research with other substance dependent populations shows that subgroups of participants may benefit from a treatment although the entire population does not.
We conducted a secondary analysis of POATS data to determine whether a subgroup of participants benefited from drug counseling in addition to buprenorphine-naloxone and medical management, either due to greater problem severity or more exposure to counseling as a result of greater treatment adherence. Problem severity was measured by a history of heroin use, higher Addiction Severity Index drug composite score, and chronic pain. Adequate treatment adherence was defined a priori as attending at least 60% of all offered sessions.
Patients who had ever used heroin and received drug counseling were more likely to be successful (i.e., abstinent or nearly abstinent from opioids) than heroin users who received medical management alone, but only if they were adherent to treatment and thus received adequate exposure to counseling (OR=3.7, 95% CI=1.1-11.8, p=0.03). The association between severity and outcome did not vary by treatment condition for chronic pain or ASI drug severity score.
These findings emphasize the importance of treatment adherence, and suggest that patients with prescription opioid dependence are a heterogeneous group, with different optimal treatment strategies for different subgroups.
prescription opioids; treatment; counseling
Gene polymorphisms that affect serotonin signaling modulate reactivity to salient stimuli and risk for emotional disturbances. Here, we hypothesized that these serotonin genes, which have been primarily explored in depressive disorders, could also have important implications for drug addiction, with the potential to reveal important insights into drug symptomatology, severity, and/or possible sequelae such as dysphoria.
Using an imaging genetics approach, the current study tested in 62 cocaine abusers and 57 healthy controls the separate and combined effects of variations in the serotonin transporter (5-HTTLPR) and monoamine oxidase A (MAOA) genes on processing of aversive information. Reactivity to standardized unpleasant images was indexed by a psychophysiological marker of stimulus salience (i.e., the late positive potential (LPP) component of the event-related potential) during passive picture viewing. Depressive symptomatology was assessed with the Beck Depression Inventory (BDI).
Results showed that, independent of diagnosis, the highest unpleasant LPPs emerged in individuals with MAOA-Low and at least one ‘Short’ allele of 5-HTTLPR. Uniquely in the cocaine participants with these two risk variants, higher unpleasant LPPs correlated with higher BDI scores.
Taken together, these results suggest that a multilocus genetic composite of monoamine signaling relates to depression symptomatology through brain function associated with the experience of negative emotions. This research lays the groundwork for future studies that can investigate clinical outcomes and/or pharmacogenetic therapies in drug addiction and potentially other psychopathologies of emotion dysregulation.
cocaine addiction; imaging genetics; depression; comorbidity; 5-HTTLPR; MAOA; event-related potentials
Time-varying associations of 185 at-risk men’s (from the Oregon Youth Study) substance use with that of their peers and partner over a 10-year period (ages 23 to 32 years) were examined. Moderation of effects by time with peers and partner and their age were tested.
Growth models were used to predict changes in heavy episodic drinking (HED) alcohol use and marijuana use as a function of substance use by their female partners and male peers.
Time with peers and peer substance use significantly predicted HED (ORs=1.6, 2.3), alcohol use (ORs=1.6, 2.1), volume of alcohol use (IRRs = 1.5, 1.3), and marijuana use (ORs=12.8, 1.7); peer marijuana use predicted volume of marijuana use (B=2.5). Partner substance use significantly predicated marijuana volume (B=2.7). Partner alcohol use predicted alcohol volume (IRR=1.1), but was moderated by time with partner and age (IRR=1.0). Time with partner and partner marijuana use predicted marijuana use (OR=0.5, 2.7), as did the interaction of the two (OR=3.8).
Outcome-specific substance use of peers and partners was significantly associated with indicators of alcohol and marijuana use in men’s early adulthood, with robust effects of peer substance use through age 30 years and with time spent with peers influencing alcohol use. Time with partner was protective against marijuana use unless the partner used marijuana. Peers and partners should be considered in intervention efforts to effectively reduce men’s substance use in early adulthood.
Substance use; Alcohol; Marijuana; Peers; Partner; Free time
Legal medical marijuana has been commercially available on a widespread basis in Colorado since mid-2009; however, there is a dearth of information about the impact of marijuana commercialization on impaired driving. This study examined if the proportions of drivers in a fatal motor vehicle crash who were marijuana-positive and alcohol-impaired, respectively, have changed in Colorado before and after mid-2009 and then compared changes in Colorado with 34 non-medical marijuana states (NMMS).
Thirty-six 6-month intervals (1994–2011) from the Fatality Analysis Reporting System were used to examine temporal changes in the proportions of drivers in a fatal motor vehicle crash who were alcohol-impaired (≥ 0.08 g/dl) and marijuana-positive, respectively. The pre-commercial marijuana time period in Colorado was defined as 1994–June 2009 while July 2009–2011 represented the post-commercialization period.
In Colorado, since mid-2009 when medical marijuana became commercially available and prevalent, the trend became positive in the proportion of drivers in a fatal motor vehicle crash who were marijuana-positive (change in trend, 2.16 (0.45), p < 0.0001); in contrast, no significant changes were seen in NMMS. For both Colorado and NMMS, no significant changes were seen in the proportion of drivers in a fatal motor vehicle crash who were alcohol-impaired.
Prevention efforts and policy changes in Colorado are needed to address this concerning trend in marijuana-positive drivers. In addition, education on the risks of marijuana-positive driving needs to be implemented.
medical marijuana; traffic fatalities; alcohol-impaired driving; marijuana-positive driving; drugged driving
Characterize longitudinal patterns of drug use careers and identify determinants of drug use frequency across cohorts of primary heroin, methamphetamine (MA) and cocaine users.
Pooled analysis of prospective cohort studies.
Illicit drug users recruited from community, criminal justice and drug treatment settings in California, USA.
We used longitudinal data on from five observational cohort studies featuring primary users of heroin (N=629), cocaine (N=694) and methamphetamine (N=474). The mean duration of follow-up was 20.9 years.
Monthly longitudinal data was arranged according to five health states (incarceration, drug treatment, abstinence, non-daily and daily use). We fitted proportional hazards (PH) frailty models to determine independent differences in successive episode durations. We then executed multi-state Markov (MSM) models to estimate probabilities of transitioning between health states, and the determinants of these transitions.
Across primary drug use types, PH frailty models demonstrated durations of daily use diminished in successive episodes over time. MSM models revealed primary stimulant users had more erratic longitudinal patterns of drug use, transitioning more rapidly between periods of treatment, abstinence, non-daily and daily use. MA users exhibited relatively longer durations of high-frequency use. Criminal engagement had a destabilizing effect on health state durations across drug types. Longer incarceration histories were associated with delayed transitions towards cessation.
PH frailty and MSM modeling techniques provided complementary information on longitudinal patterns of drug abuse. This information can inform clinical practice and policy, and otherwise be used in health economic simulation models, designed to inform resource allocation decisions.
drug use careers; longitudinal; health state transitions; proportional hazards frailty; multi-state Markov