Latent classes of heroin and cocaine users predict unique HIV/HCV risk factors

Background

Patterns of heroin and cocaine use vary and may be associated with unique risk factors for bloodborne infections.

Methods

Latent class analysis identified sub-populations of 552 heroin and cocaine users in Baltimore, Maryland. Using latent class regression, these classes were analyzed for associations with demographic characteristics, risky behaviors, Hepatitis C, and HIV.

Results

Three classes were found: Crack/Nasal-Heroin users (43.5%), Polysubstance users (34.8%), and Heroin Injectors (21.8%). Compared to Polysubstance users, Crack/Nasal-Heroin users were almost 7 times more likely to identify as Black (OR = 6.97, 95% CI = 4.35–11.2). Sharing needles was over 2.5 times more likely among Polysubstance users than among Heroin Injectors (OR = 2.66, 95% CI = 1.49–4.75). Crack/Nasal-Heroin users were 2.5 times more likely than Polysubstance users to exchange drugs for sex (OR = 2.50, 95% CI = 1.22–5.13). Crack/Nasal-Heroin users were less likely than Heroin Injectors to have Hepatitis C (OR = 0.10, 95% CI = 0.06–0.18), but no significant differences were found for HIV.

Conclusions

Subpopulations of cocaine and heroin users differed in demographic classifications, HIV-risk behaviors, and Hepatitis C infection. All subpopulations included substantial numbers of HIV-positive individuals. Findings provide further evidence that non-injection drug users face significant infectious disease risk.     

Predictive model accuracy in estimating last Δ(9)-tetrahydrocannabinol (THC) intake from plasma and whole blood cannabinoid concentrations in chronic, daily cannabis smokers administered subchronic oral THC

Background

Determining time since last cannabis/Δ⁹-tetrahydrocannabinol (THC) exposure is important in clinical, workplace, and forensic settings. Mathematical models calculating time of last exposure from whole blood concentrations typically employ a theoretical 0.5 whole blood-to-plasma (WB/P) ratio. No studies previously evaluated predictive models utilizing empirically-derived WB/P ratios, or whole blood cannabinoid pharmacokinetics after subchronic THC dosing.

Methods

Ten male chronic, daily cannabis smokers received escalating around-the-clock oral THC (40–120 mg daily) for 8 days. Cannabinoids were quantified in whole blood and plasma by two-dimensional gas chromatography–mass spectrometry.

Results

Maximum whole blood THC occurred 3.0 h after the first oral THC dose and 103.5 h (4.3 days) during multiple THC dosing. Median WB/P ratios were THC 0.63 (n = 196), 11-hydroxy-THC 0.60 (n = 189), and 11-nor-9-carboxy-THC (THCCOOH) 0.55 (n = 200). Predictive models utilizing these WB/P ratios accurately estimated last cannabis exposure in 96% and 100% of specimens collected within 1–5 h after a single oral THC dose and throughout multiple dosing, respectively. Models were only 60% and 12.5% accurate 12.5 and 22.5 h after the last THC dose, respectively.

Conclusions

Predictive models estimating time since last cannabis intake from whole blood and plasma cannabinoid concentrations were inaccurate during abstinence, but highly accurate during active THC dosing. THC redistribution from large cannabinoid body stores and high circulating THCCOOH concentrations create different pharmacokinetic profiles than those in less than daily cannabis smokers that were used to derive the models. Thus, the models do not accurately predict time of last THC intake in individuals consuming THC daily.     

Comparative study on the efficacy of Allium sativum (garlic) in reducing some heavy metal accumulation in liver of wistar rats

Scope

Heavy metals are known to cause damage through indirect oxidative effects. This study was undertaken to compare the therapeutic efficacy and protective ability of garlic extracts on reducing toxicity induced by mercury, lead and cadmium in the liver.

Methods and results

Rats were fed with rat chow mixed with raw garlic (7% w/w) while mercury (10 ppm), cadmium (200 ppm) and lead (100 ppm) were given in drinking water. Garlic was administered either at the same time with the metals (group 2), a week after exposure to heavy metals (group 3) or a week before heavy metal exposure (group 4) for 6 weeks. The heavy metal accumulations in the liver were determined using AAS. The percentage protection showed a time-dependent effect and was significantly (P < 0.01) higher for cadmium compared to mercury and lead-treated groups. Analysis between the groups showed that garlic treatment after exposure had a significantly (P < 0.05) higher percentage protection when compared with other modes.

Conclusion

These results suggest that garlic offered more hepatoprotective effect to cadmium followed by mercury and least protection to lead at the selected dose of each metal in this study through the processes of uptake, assimilation and elimination of these metals.     

Early life exposure to violence and substance misuse in adulthood-The first Brazilian national survey

Background

Substance misuse has been a major source of health and social problems in developing societies as it has been elsewhere. There is a growing body of evidence from developed nations linking early exposure to violence in childhood with substance misuse in adulthood. The role of depression on this association is not clear. This study estimates the association between early life exposure to violence, alcohol disorders and illegal substance use in adulthood and the role of depression on these associations using a national Brazilian sample.

Methods

The first Brazilian National Alcohol Survey gathered information on early exposure to violence and use of psychoactive substances in 1880 participants aged 20 to 60 years old selected at random from the Brazilian household population. We used weighted logistic regression to calculate adjusted odds ratios for the associations between early exposure to violence and substance misuse. To assess the mediating effect of depression on these associations we used the Sobel–Goodman Mediation Test.

Results

Witnessing violence during childhood or adolescence was reported by nearly 20% of the participants whilst over 8% reported having been victims of at least one form of violence. There was a statistically significant association between early exposure to violence and alcohol abuse and/or dependence and use of illegal substances in adulthood with a dose–response relationship. Depression partially explained the association between early exposure to violence with alcohol dependence (18.77% p < 0.001) and did not have a statistically significant mediating effect on the association with illegal substance use (5.83% p = 0.220).

Conclusions

Adverse early life events may affect individual's susceptibility to substance misuse which can be partially mediated by depression. Prevalence of substance misuse in adulthood may be in part attributed to the prevalence of adverse childhood experience. While prevention is the ideal goal, detection and intervention with children exposed to violence must be prioritised.     

Demographic, emotional and social determinants of cannabis use in early pregnancy: the Generation R study

Aims

To ascertain demographic, emotional and social determinants of cannabis use in early pregnancy.

Design

This study was embedded in the Generation R study, a multiethnic population-based cohort of parents and their children, followed from pregnancy to childhood.

Setting

Rotterdam, The Netherlands.

Participants

Mothers enrolled in pregnancy who answered questions about their own and their partners substance use before and during pregnancy (n = 7610).

Measurements

Using self-report questionnaires, information was collected on maternal demographics, psychopathology, delinquency, childhood trauma, social stress, family functioning, and parental alcohol, tobacco and substance use. Multinomial logistic regression analysis was used, with non-using women as reference.

Findings

246 (3.2%) women used cannabis before pregnancy and 220 (2.9%) women used cannabis both before and during pregnancy. The strongest determinant for maternal cannabis use during pregnancy was cannabis use by the biological father of the child (OR = 38.56; 95%CI = 26.14–58.88). Maternal cannabis use during pregnancy was also independently associated with being single (OR = 4.25; 95%CI = 2.33–7.75) or having a partner without being married (OR = 2.75; 95%CI = 1.56–4.85), childhood trauma (OR = 1.39; 95%CI = 1.22–1.57) and delinquency (OR = 3.37; 95%CI = 1.90–5.98), but not with maternal age, ethnicity, psychopathology, family functioning and perceived stress. Being religious was protective (Islam: OR = 0.25; 95%CI = 0.09–0.65) for maternal cannabis use during pregnancy. Additionally, lower educational level determined continued cannabis use in ever-users (OR = 3.22; 95%CI = 1.54–6.74).

Conclusions

Our results showed that multiple demographic, emotional and social characteristics were associated with maternal cannabis use. These characteristics should be considered when investigating offspring exposed to cannabis in utero, as they may play an important role in mother–child interaction and child development.     

All-cause mortality among individuals with disorders related to the use of methamphetamine: A comparative cohort study

Background

Understanding the mortality rate of methamphetamine users, especially in relation to other drug users, is a core component of any evaluation of methamphetamine-related harms. Although methamphetamine abuse has had a major impact on United States (US) drug policy and substance-abuse treatment utilization, large-scale cohort studies assessing methamphetamine-related mortality are lacking.

Methods

The current study identified cohorts of individuals hospitalized in California from 1990 to 2005 with ICD-9 diagnoses of methamphetamine- (n = 74,139), alcohol- (n = 582,771), opioid- (n = 67,104), cannabis- (n = 46,548), or cocaine-related disorders (n = 48,927), and these groups were followed for up to 16 years. Age-, sex-, and race-adjusted standardized mortality rates (SMRs) were generated.

Results

The methamphetamine cohort had a higher SMR (4.67, 95% CI 4.53, 4.82) than did users of cocaine (2.96, 95% CI 2.87, 3.05), alcohol (3.83, 95% CI 3.81, 3.85), and cannabis (3.85, 95% CI 3.67, 4.03), but lower than opioid users (5.71, 95% CI 5.60, 5.81).

Conclusions

Our study demonstrates that individuals with methamphetamine-use disorders have a higher mortality risk than those with diagnoses related to cannabis, cocaine, or alcohol, but lower mortality risk than persons with opioid-related disorders. Given the lack of long-term cohort studies of mortality risk among individuals with methamphetamine-related disorders, as well as among those with cocaine- or cannabis-related conditions, the current study provides important information for the assessment of the comparative drug-related burden associated with methamphetamine use.     

Sensation-seeking predicts initiation of daily smoking behavior among American Indian high school students

Purpose

American Indian (AI) youth have a high risk of smoking initiation. Sensation-seeking, defined as the tendency to seek novel and thrilling experiences, has been associated with smoking initiation in other groups but has never been examined in AI youth.

Methods

Data were from the Voices of Indian Teens Project (VOICES), a longitudinal study of AI youth from seven high schools in four AI communities in the western United States. Participants completed annual surveys in school over a three-year period. Our sample comprised 764 students who were non-smokers at baseline. Smoking initiation was defined as endorsement of daily smoking after baseline. We used binary logistic regression to evaluate the association of baseline sensation-seeking with odds of daily smoking initiation, stratified by gender.

Results

Participants were 353 males and 411 females aged 13 to 21 years at baseline. After adjusting for covariates, baseline sensation-seeking correlated with smoking initiation differently in males and females. Sensation-seeking did not predict daily smoking in males. Among females, however, higher sensation-seeking scores at baseline predicted daily smoking in both the unadjusted (odds ratio = 1.4; 95% CI = 1.1–1.8; p = 0.005) and covariate-adjusted (odds ratio = 1.3; 95% CI = 1.0–1.6; p = 0.04) models.

Conclusion

Gender-specific prevention programs may be warranted in addressing different risk-factor profiles in this high-risk population.     

Development and validation of the Cannabis Refusal Self-Efficacy Questionnaire (CRSEQ) in adult cannabis users in treatment

Background

There are few valid clinical assessment instruments for cannabis. Self-efficacy, or the ability of users to resist temptation, is a central feature of social cognitive theory. This study outlines the development and validation of the Cannabis Refusal Self-Efficacy Questionnaire (CRSEQ), which measures the situational confidence to refuse cannabis.

Method

One thousand two hundred and forty-six patients referred for cannabis assessment completed the CRSEQ including measures of cannabis consumption and dependence severity (Severity of Dependence Scale-Cannabis, SDS-C). The CRSEQ was subject to independent exploratory (n = 621, mean age 26.88, 78.6% male) and confirmatory (n = 625, mean age 27.51, 76.8% male) factor analysis.

Results

Three factors: Emotional Relief, Opportunistic and Social Facilitation were identified. They provided a good statistical and conceptual fit for the data. Emotional Relief cannabis refusal self-efficacy was identified as most predictive of cannabis dependence, after controlling for cannabis consumption.

Conclusions

The CRSEQ is recommended as a psychometrically sound and clinically useful measure for cannabis misuse treatment planning and assessment.     

Non-opioid induction of morphine-6-glucuronide synthesis is elicited by prolonged exposure of rat hepatocytes to heroin

Background

Liver metabolism of morphine leads to the formation of morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), the latter possessing strong opioid activity that however differs from that of the parent compound. In previous studies conducted in rats we have shown that repeated in vivo exposure to phenanthrene class of mu opioid receptor (MOR) agonists or antagonists (heroin, morphine, and naltrexone), but not to non-phenanthrene class of MOR agonist methadone, affects morphine glucuronidation by liver microsomes.

Methods

In the present study, we measured the in vitro formation of M3G and M6G by rat hepatocytes incubated for 120 min with morphine (0.1–1.0 mM) after 72 h pre-incubation with one of the following MOR agonists: heroin (3.3 or 6.6 μM), morphine (7.8 μM), or methadone (12 μM). The MOR antagonist naltrexone (10 or 25 μM) was also tested, alone or in combination with heroin. The amount of M3G and M6G synthesized was then measured by HPLC method.

Results

Heroin inhibited M3G synthesis and induced the formation of M6G, which under basal conditions is not synthesized in rats. Heroin effects were not blocked by naltrexone. Morphine, but not methadone, produced effects similar to those of heroin but more modest in intensity. Pre-incubation with naltrexone alone slightly increased M3G synthesis, but had no effect on M6G formation.

Conclusions

These results are in agreement with those of previous ex vivo studies and indicate that exposure to heroin or, to a lesser extent, morphine, can affect morphine glucuronidation via direct non-opioid actions on the hepatocytes.     

Intravenous gestational nicotine exposure results in increased motivation for sucrose reward in adult rat offspring

Background

Prenatal tobacco smoke exposure is associated with alterations in motivated behavior in offspring, such as increased consumption of highly palatable foods and abused drugs. Animal models show that gestational nicotine (GN) exposure mediates changes in responding for sucrose and drug reward.

Methods

A novel, intermittent low-dose intravenous (IV) exposure model was used to administer nicotine (0.05 mg/kg/injection) or saline 3 × /day to rats on gestational days 8–21. Two experiments investigated the effect of IV GN on (1) the habituation of spontaneous locomotor activity and on (2) sucrose reinforced responding in offspring. For the operant experiments, animals acquired fixed-ratio (FR-3) responding for sucrose, 26% (w/v), and were tested on varying concentrations (0, 3, 10, 30, and 56%; Latin-square) according to a FR-3, and then a progressive-ratio (PR) schedule. Male and female adult offspring were used.

Results

IV GN did not alter birth or growth weight, or the number of pups born. No between-group differences in habituation to spontaneous locomotor activity were observed. FR testing produced an inverted U-shaped response curve, and rats showed peak responding for 10% sucrose reinforcement. Neither gestation nor sex affected responding, suggesting equivalent sensitivity to varying sucrose concentrations. PR testing revealed that GN rats showed greater motivation for sucrose reinforcement relative to controls.

Conclusions

A low-dose, IV GN exposure model resulted in increased motivation to respond for sucrose reinforcement in adult offspring. This suggests that using a low number of cigarettes throughout pregnancy will result in increased motivation for highly palatable foods in adult, and perhaps, adolescent offspring.     

Smoking family, secondhand smoke exposure at home, and nicotine addiction among adolescent smokers

Introduction

Smoking family predicts adolescent smoking, but whether the level of nicotine addiction is affected by exposure to secondhand smoke (SHS) is unclear. We investigated the associations of smoking family and SHS exposure at home with morning smoking and heavier smoking among Chinese adolescent smokers.

Methods

In a school-based anonymous survey, 2182 adolescent smokers reported their smoking behaviors, smoking status of family members and peers, and SHS exposure at home and outside home in the past 7 days. Families with one or more smoking members (excluding the subject) were classified as smoking families and otherwise as non-smoking families. Smoking or wanting to smoke first thing in the morning (morning smoking), and consuming more cigarettes (heavier smoking) denoted higher levels of nicotine addiction. Regression analysis yielded adjusted odds ratios (AORs) for morning smoking and β-coefficients for heavier smoking adjusting for potential confounders.

Results

Living with siblings and other co-residing family members who smoked was significantly associated with morning smoking and heavier smoking. Compared with non-smoking families without SHS exposure at home, the AORs (95% CI) for morning smoking were 0.99 (0.76 to 1.29) for 0 day/week, 1.19 (0.95 to 1.50) for 1–3 days/week, 1.76 (1.41 to 2.21) for 4–7 days/week (p for trend < 0.001) and 1.50 (1.23 to 1.83) for any days/week of SHS exposure at home in smoking families. Similarly, 4–6 days/week of SHS exposure at home significantly predicted heavier smoking.

Conclusion

Living with smoking family members and SHS exposure at home are associated with nicotine addiction in Chinese adolescent smokers.     

The effect of telephonic patient support on treatment for opioid dependence: outcomes at one year follow-up

Objective

The present study examined the impact of a telephonic patient support program known as HereToHelp™ (HTH) on compliance and treatment outcomes among opioid dependent (OD) patients new to buprenorphine treatment (BUP).

Method

A total of 1426 OD patients new to BUP were randomized to receive BUP alone (standard care) or BUP plus the HTH patient support program. All patients completed the Addiction Severity Index (ASI) at the time of enrollment, and at 12 months post-enrollment.

Results

Subjects randomized to the HTH support program who accepted at least 3 care coach intervention calls were more compliant with BUP than the standard care group at month 12 (64.4% vs. 56.1%, χ² = 5.09, p < .025). Compared to patients who were non-compliant with BUP, compliant patients reported significantly lower scores on all 7 of the ASI composite scores, indicating lower severity on addiction-related problems.

Conclusions

The HTH intervention seemed to improve patient treatment outcomes indirectly by improving compliance with BUP. Supplementing BUP with a structured, telephonic compliance-enhancement program is an effective way to improve compliance with medication which then improves patient outcomes.     

Using population physiologically based pharmacokinetic modeling to determine optimal sampling times and to interpret biological exposure markers: The example of occupational exposure to styrene

Background

Biomonitoring of chemicals in the workplace provides an integrated characterization of exposure that accounts for uptake through multiple pathways and physiological parameters influencing the toxicokinetics.

Objectives

We used the case of styrene to (i) determine the best times to sample venous blood and end-exhaled air, (ii) characterize the inter-individual variability in biological levels following occupational exposure and (iii) propose biological limit values using a population physiologically based pharmacokinetic (PBPK) model.

Methods

We performed Monte Carlo simulations with various physiological, exposure and workload scenarios. Optimal sampling times were identified through regression analyses between levels in biological samples and 24-h area under the arterial blood concentration vs. time curve. We characterized the variability in levels of styrene in biological samples for exposures to a time weighted average (TWA) of 20 ppm.

Results

Simulations suggest that the best times to sample venous blood are at the end of shift in poorly ventilated workplaces and 15 min after the shift in highly ventilated workplaces. Exhaled air samples are most informative 15 min after the shift. For a light workload, simulated styrene levels have a median (5th–95th percentiles) of 0.4 mg/l (0.2–0.6) in venous blood at the end of shift and 0.5 ppm (0.3–0.8) in exhaled air 15 min after the end of shift.

Conclusion

This study supports the current BEI^® of the ACGIH of 0.2 mg/l of styrene in venous blood at the end of shift and indicates a biological limit value of 0.3 ppm in end-exhaled air 15 min after the end of shift.     

Occupational exposure to indium: what does biomonitoring tell us?

Background

The industrial uses of indium, a rare metal with no known physiological role in humans, have increased dramatically over the past 15 years.The results of animal toxicity studies showing pulmonary and systemic effects as well as some reports in workers have created a growing concern about the possible occurrence of toxic effects in exposed workers. Validated biomarkers to assess exposure to indium are not available.

Objectives

This work aimed at investigating the kinetics of indium in urine (In-U) and plasma (In-Pl) in workers manufacturing In ingots and mainly exposed to hardly water-soluble In compounds. All nine workers from the In department of a large metallurgical concern participated in the study as well as 5 retired workers and 20 controls.

Methods

Personal breathing zone air was collected throughout the work shift on Monday and Friday. Blood and urine samples were collected, before and after the shift, on the same day as the air sampling and on preshift the next Monday after a non-working week-end. Moreover, rats were given either InCl₃ by intraperitoneal injection or In₂O₃ by pharyngeal aspiration, In was followed in plasma during 120 days and measured in tissues 120 days after exposure.

Results

Higher In-Pl and In-U concentrations were found in both current (range 0.32–12.61 μg/L plasma; 0.22–3.50 μg/g creat) and former (0.03–4.38 μg/L plasma; 0.02–0.69 μg/g creat) workers compared with controls (<0.03 μg/L plasma; <0.02 μg/g creat). Both biological parameters were highly correlated but no correlation was found between In-air (10–1030 μg/m³) and In-Pl or In-U. Normalizing In-U by the urinary creatinine concentration reduced the inter- (from 90% to 70%) and intra-individual variability (from 54% to 35%). In-Pl remained remarkably stable along the working week (inter- and intra-individual variability: 89% and 10%, respectively). Neither In-U nor In-Pl significantly increased during the day or the week. A week-end without occupational exposure was not sufficient to reach the background In-Pl and In-U levels measured in controls. The results of the experimental investigations confirmed the hypothesis that inhalation of hardly soluble In compounds may cause accumulation of In in the body leading to a prolonged “endogenous exposure” from both a lung depot of “insoluble” particles that are progressively absorbed and from a retention depot in other internal organs.

Conclusion

This study shows that in workers exposed to hardly soluble In compounds, In-U and In-Pl are very sensitive to detect exposure and mainly reflect long-term exposure. In-Pl levels are particularly stable for a given individual. In-U might be more influenced than In-Pl by recent exposure. Both parameters remained high years after withdrawal from exposure, indicating a possible endogenous exposure and a prolonged risk of pulmonary and systemic diseases even after work exposure has ceased.     

Perceived support to stay quit: What happens after delivery?

Objective

To assess whether perceived changes in postpartum support were associated with postpartum return to smoking.

Study design

This is a prospective repeated measures, mixed methods observational study. Sixty-five women who smoked prior to pregnancy were recruited at delivery and surveyed at 2, 6, 12, and 24 weeks postpartum; in-depth interviews were conducted when participants reported smoking.

Results

Fifty-two percent self identified as White, non-Hispanic. Forty-seven percent resumed smoking by 24 weeks postpartum. Women who had returned to smoking by 24 weeks had a significantly larger decrease in perceived smoking-specific support than women who remained abstinent (p < 0.001). By 24-week postpartum follow-up, only 24% of women reported that an obstetric clinician had discussed how to quit/stay quit. When qualitatively interviewed, more than half of women reported having no one to support them to stay quit or quit smoking.

Conclusion

Following delivery, women lack needed smoking-specific support. Decline in perceived smoking-specific support from family and friends is associated with postpartum smoking resumption.     

Drinking and driving among immigrant and US-born Hispanic young adults: results from a longitudinal and nationally representative study

Objective

To evaluate the risk factors associated with the initiation of driving under the influence (DUI) among Hispanics in a longitudinal and nationally-representative sample of adolescents and young adults. Specifically, this study tests the effect of demographic variables, individual-level risk factors, and eco-processes (e.g., peer drug use, parental involvement) during adolescence on DUI among Hispanic young adults.

Methods

Data were derived from 1734 Hispanic adolescents surveyed for the National Longitudinal Study of Adolescent Health (Add Health). Survey logistic regression procedures were used to examine the effects of nativity status on DUI initiation, to evaluate the independent effect of each risk factor (demographic, individual-level, and eco-processes), and to identify whether and to what extent these factors are associated with the initiation of DUI.

Results

The overall prevalence of DUI initiation was 18.3%. Differences were observed in the rates of DUI initiation by nativity status: first-generation immigrants reported the lowest rates of DUI initiation (15.4%) when compared with second-generation US-born Hispanic youth (17.4%) and third-generation and beyond US-born Hispanic youth (21.5%). US-born Hispanic youth were also more likely to report higher frequency of alcohol use (t = 3.46, p = 0.001) and marijuana use (t = 2.34, p = 0.021) compared to immigrant adolescents. After adjusting for a number of risk factors, men (OR = 2.86), marijuana users (OR = 1.98), and those who reported feeling safe in their neighborhoods (OR = 2.02) were at an increased risk DUI initiation.

Conclusions

Findings provide support for the “immigrant paradox”: immigrant youth reported lower rates of DUI initiation and other high-risk behaviors when compared with US-born Hispanic youth.     

Trajectories of criteria of nicotine dependence from adolescence to early adulthood

Background

To identify patterns and correlates of developmental trajectories of DSM-IV nicotine dependence criteria from adolescence to early adulthood.

Methods

The analytical sample of lifetime smokers (N = 877) is from a longitudinal cohort of 6th–10th graders drawn from an urban school system. Subjects were interviewed 5 times at 6-month intervals and once 4.5 years later. Growth mixture models were estimated to identify trajectories of DSM-IV nicotine dependence criteria over ages 12–23.

Results

A four-class solution fitted the data best: No dependence criteria (Class 1, 32.0%); Early onset/Chronic course (Class 2, 26.1%); Early onset/Remission (Class 3, 15.4%); Late onset (Class 4, 26.5%). There appeared to be three critical periods. At ages 12–15, symptoms increased rapidly. As of age 16, the Early onset/Chronic class stabilized at high levels of symptoms, the Early onset/Remission class started its symptomatic decline, and the Late onset class experienced a sharp increase in symptoms. At age 20, there was a convergence in the prevalence of symptoms experienced at high (Classes 2 and 4) and low levels (Classes 1 and 3). Extensiveness of smoking and marijuana use were associated with higher baseline levels of nicotine dependence criteria. Anxiety disorders were associated with all three symptomatic trajectories. Parental smoking and nicotine dependence were associated specifically with the Early/Chronic class, while pleasant initial sensitivity and earlier onset ages of cigarette and marijuana use characterized the two early onset classes (2 and 3).

Conclusions

Trajectories of dependence criteria constitute an advantageous phenotype for research and intervention over static summaries of smoking behaviors.     

Nicotine self-administration and reinstatement of nicotine-seeking in male and female rats

Background

Tobacco addiction is a relapsing disorder that constitutes a substantial worldwide health problem, with evidence suggesting that nicotine and nicotine-associated stimuli play divergent roles in maintaining smoking behavior in men and women. While animal models of tobacco addiction that utilize nicotine self-administration have become more widely established, systematic examination of the multiple factors that instigate relapse to nicotine-seeking have been limited. Here, we examined nicotine self-administration and subsequent nicotine-seeking in male and female Sprague-Dawley rats using an animal model of self-administration and relapse.

Methods

Rats lever pressed for nicotine (0.03 and 0.05 mg/kg/infusion, IV) during 15 daily 2-h sessions, followed by extinction of lever responding. Once responding was extinguished, we examined the ability of previously nicotine-paired cues (tone + light), the anxiogenic drug yohimbine (2.5 mg/kg, IP), a priming injection of nicotine (0.3 mg/kg, SC), or combinations of drug + cues to reinstate nicotine-seeking.

Results

Both males and females readily acquired nicotine self-administration and displayed comparable levels of responding and intake at both nicotine doses. Following extinction, exposure to the previously nicotine-paired cues or yohimbine, but not the nicotine-prime alone, reinstated nicotine-seeking in males and females. Moreover, when combined with nicotine-paired cues, both yohimbine and nicotine enhanced reinstatement. No significant sex differences or estrous cycle dependent changes were noted across reinstatement tests.

Conclusions

These results demonstrate the ability to reinstate nicotine-seeking with multiple modalities and that exposure to nicotine-associated cues during periods of a stressful state or nicotine can increase nicotine-seeking.     

Patterns of alcohol use and sexual behaviors among current drinkers in Cape Town, South Africa

Objective

This study examined the association between alcohol use and sexual behaviors among South African adults who reported current drinking.

Method

Street-intercept surveys were administered to adults residing in neighborhoods in a South African township.

Results

Analyses were restricted to participants reporting current drinking (N = 1285; mean age = 32; 27% women; 98% Black). Most participants (60%) reported heavy episodic drinking (i.e., 5 or more drinks on a single occasion) at least once per week in the past 30 days. Compared to non-heavy episodic drinkers, participants who reported heavy episodic drinking were more likely to drink before sex (79% vs. 66%) and have sex with a partner who had been drinking (59% vs. 44%). Overall, drinking before sex (self or partner) and heavy episodic drinking was associated with multiple sexual partners, discussing condom use with sexual partner(s), and proportion of protected sex. The frequency of condom use varied among participants with steady, casual, or both steady and casual sexual partners.

Conclusions

Alcohol use among South African adults is associated with sexual risk behaviors, but this association differs by partner type. Findings suggest the need to strengthen alcohol use components in sexual risk reduction interventions especially for participants with both steady and casual sex partners.