Comparison between self-report and hair analysis of illicit drug use in a community sample of middle-aged men

Discrepancies between biological assays and self-report of illicit drug use could undermine epidemiological research findings. Two objectives of the present study are to examine the degree of agreement between self-reported illicit drug use and hair analysis in a community sample of middle-aged men, and to identify factors that may predict discrepancies between self-report and hair testing. Male participants followed since 1972 were interviewed about substance use, and hair samples were analyzed for marijuana, cocaine, opiates, phencyclidine (PCP) and methamphetamine using radioimmunoassay and gas chromatography-mass spectrometry (GC-MS) techniques. Self-report and hair testing generally met good, but not excellent, agreement. Apparent underreporting of recent cocaine use was associated with inpatient hospitalization for the participant's most recent quit attempt, younger age, identifying as African American or other, and not having a diagnosis of antisocial personality disorder. The overestimate of marijuana use relative to hair test was associated with frequent use since 1972 and providing an inadequate hair sample. Additional research is needed to identify factors that differentially affect the validity of both hair drug testing and self-report.     

Prenatal and postnatal cocaine exposure enhances the induction and expression of locomotor sensitization to cocaine in rats

Prenatal and postnatal exposure to cocaine can affect the development and function of the central nervous system in offspring. It also produces changes in cocaine-induced dopamine release and increases cocaine self-administration and cocaine-induced conditioned place preference. Further, prenatal cocaine exposure involves greater risk for development of a substance use disorder in adolescents. Therefore, the objective of this study was to determine the effect of prenatal and postnatal cocaine exposure on locomotor sensitization in rats. A group of pregnant female Wistar rats were administered daily from day GD0 to GD21 with cocaine (cocaine pre-exposure group) and another group pregnant female rats were administered daily with saline (saline pre-exposure group). During lactation (PND0 to PND21) pregnant rats also received cocaine administration or saline, respectively. Of the litters resulting of the cocaine pre-exposed and saline pre-exposed pregnant female groups, only the male rats were used for the recording of the locomotor activity induced by different doses of cocaine (1, 5, 10, 20 and 40 mg/Kg/day) during the induction and expression of locomotor sensitization at different postnatal ages (30, 60, 90 and 120 days), representative of adolescence and adult ages. The study found that prenatal and postnatal cocaine exposure enhanced locomotor activity and locomotor sensitization, and such increase was dose- and age-dependent. This suggests that prenatal and postnatal cocaine exposure can result in increased vulnerability to cocaine abuse in young and adult humans.     

Prenatal cocaine exposure and school-age intelligence

Assessments of the possible consequences of prenatal exposure to cocaine have been limited by lack of control for socio-demographic confounders and lack of follow-up into the school years. We evaluated intelligence at ages 6–9 years in 88 children from a cohort of 280 born between September 1, 1985 and August 31, 1986 and identified at birth as cocaine-exposed, and in a group of unexposed (n=96) births of comparable gender and birthweight. IQ scores did not differ between children with and without prenatal exposure to cocaine (mean 82.9 vs. 82.4, difference=0.5 points, 95% CI-3.1, 4.1); results were unchanged with adjustment for child height, head circumference and prior residence in a shelter or on the street, and for caregiver IQ and home environment (mean difference=2.2 points, 95% CI-1.5, 5.8).     

Predictors of disclosure of continued cocaine use

Lack of disclosure of substance use is common in research and treatment settings and is frequently higher at follow-up than at baseline interviews. The aim of this study was to determine predictors of cocaine use disclosure at follow-up among 525 individuals who reported and tested positive for baseline use. Measurements included self-reported quantity and frequency of use, and hair analysis by radioimmune assay. Forty-two percent of individuals with biochemical evidence of continued cocaine use denied this use. In adjusted analyses, self-reported substance abuse treatment contact after enrollment was associated with lower disclosure (OR 0.63, 95% CI 0.43, 0.93). Other predictors were race, hair cocaine level, and opiates in hair. Failure to stop use after seeking treatment may result in reduced disclosure of continued use, possibly because of unwillingness to admit failure.     

Neonatal neurobehavioral outcome following prenatal exposure to cocaine

This substudy of a longitudinal prospective study was designed to assess neurodevelopmental and neurobehavioral performance in newborn infants who were maternally exposed to cocaine and other drugs of abuse or the other drugs without cocaine. Sample selection procedures were designed to permit statistical control for marijuana, alcohol, and tobacco. Cocaine was assessed with both self-report and radioimmunoassay of hair. One hundred ninety-one newborns with a mean age of 43 h were assessed for 35 to 40 min on tests of reflexes, activity level, head-turning preference, tremors, nonnutritive sucking, habituation, and state. The testers were blinded to the baby's drug exposure. Cocaine-exposed newborns were developmentally at risk on the tests administered compared to infants exposed to the other three drugs alone or in some combination. A dose-response effect was found: higher amounts of cocaine were associated with higher neurobehavioral risk scores.     

Prenatal cocaine exposure: effects on locomotor activity in rat offspring

This study examines the developmental effects of prenatal exposure to cocaine in the rat, evaluated during the first month of life through open-field behavior. The offspring of Wistar dams that received 60 mg/kg of cocaine, from gestational day 8 to 22, were examined in the open-field during the second, third and fourth weeks of postnatal life in three consecutive 15-min daily sessions, starting on postnatal day (PND) 14, (PND 14–16), PND 21 (PND 21–23) and PND 28 (PND 28–30). Results show that prenatal exposure to cocaine increased total activity and rearing behavior on PND 22 and PND 29. Also, on PND 14, cocaine-exposed animals reared significantly more than control rats. There were no significant differences in the frequency of center and peripheral ambulation, nor in the defecation rate. The present results evidence alterations in the emotional behavior of rats prenatally exposed to cocaine. The delayed onset of exploration in the open-field observed in cocaine-exposed animals suggests that they take more time to become habituated to a novel and open environment.     

Chronic cocaine but not chronic amphetamine use is associated with perseverative responding in humans

Rationale Chronic drug use has been associated with increased impulsivity and maladaptive behaviour, but the underlying mechanisms of this impairment remain unclear. We investigated the ability to adapt behaviour according to changes in reward contingencies, using a probabilistic reversal-learning task, in chronic drug users and controls. Materials and methods Five groups were compared: chronic amphetamine users (n = 30); chronic cocaine users (n = 27); chronic opiate users (n = 42); former drug users of psychostimulants and opiates (n = 26); and healthy non-drug-taking control volunteers (n = 25). Participants had to make a forced choice between two alternative stimuli on each trial to acquire a stimulus–reward association on the basis of degraded feedback and subsequently to reverse their responses when the reward contingencies changed. Results Chronic cocaine users demonstrated little behavioural change in response to the change in reward contingencies, as reflected by perseverative responding to the previously rewarded stimulus. Perseverative responding was observed in cocaine users regardless of whether they completed the reversal stage successfully. Task performance in chronic users of amphetamines and opiates, as well as in former drug users, was not measurably impaired. Conclusion Our findings provide convincing evidence for response perseveration in cocaine users during probabilistic reversal-learning. Pharmacological differences between amphetamine and cocaine, in particular their respective effects on the 5-HT system, may account for the divergent task performance between the two psychostimulant user groups. The inability to reverse responses according to changes in reinforcement contingencies may underlie the maladaptive behaviour patterns observed in chronic cocaine users but not in chronic users of amphetamines or opiates.     

The differential relationship between cocaine use and marijuana use on decision-making performance over repeat testing with the Iowa Gambling Task

Decision-making deficits are a robust cognitive correlate of substance abuse, but few studies have addressed the long-term differential associations of cocaine use and marijuana (MJ) use on decision-making. This study utilized the Iowa Gambling Task (IGT), a widely used measure of decision-making, to investigate the relationship between cocaine and MJ use and IGT learning. We analyzed between and within group differences across two consecutive testing sessions in abstinent users of either MJ or cocaine. We assessed long-term correlates of the use of these drugs by evaluating users after 25 days of enforced abstinence. Results showed that both cocaine users and MJ users performed worse than controls on the total IGT net score. All groups showed learning between Session 1 and Session 2, but the cocaine users showed the smallest increase in performance. The pattern of learning from the beginning to the end (block x block) of the IGT (Session 2) was different for the drug groups, with the cocaine group showing more learning than the MJ group. Dose-related measures of cocaine use (g/week) and MJ use (joints/week) predicted IGT performance (the heavier the drug use the lower the performance). Differential correlates of cocaine use and MJ use on decision-making learning may have important implications for the development of novel treatment interventions.     

Polydrug use and its association with drug treatment outcomes among primary heroin,methamphetamine, and cocaine users

BackgroundPolydrug use may challenge effective treatment for substance use disorders. We evaluate whether secondary substance use modifies the association between treatment and primary drug use among primary heroin, cocaine and methamphetamine (MA) users.MethodsData were obtained from prospective cohort studies on people who use illicit drugs (PWUD) in California, USA. Using repeated monthly data on self-reported secondary substance use (heroin, cocaine, MA, alcohol or marijuana; ≥1 day in a month), primary drug use (≥1 day in a month), and treatment participation, collected via timeline follow-back, we fitted generalized linear mixed multiple regression models controlling for potential confounders to examine the interactions between treatment and secondary substance use on the odds of primary heroin, cocaine and MA use, respectively.ResultsIncluded in our study were 587 primary heroin, 444 primary MA, and 501 primary cocaine users, with a median of 32.4, 13.3 and 18.9 years of follow-up, respectively. In the absence of secondary substance use, treatment was strongly associated with decreased odds of primary drug use (adjusted odds ratios (aORs): 0.25, 95% CI: 0.24, 0.27, 0.07 (0.06, 0.08), and 0.07 (0.07, 0.09)) for primary heroin, MA, and cocaine users, respectively. Secondary substance use of any kind moderated these associations (0.82 (0.78, 0.87), 0.25 (0.21, 0.30) and 0.53 (0.45, 0.61), respectively), and these findings were consistent for each type of secondary substance considered. Moreover, we observed different associations in terms of direction and magnitude between secondary substance use and primary drug use during off-treatment periods across substance types.ConclusionThis study demonstrates secondary substance use moderates the temporal associations between treatment and primary drug use among primary heroin, MA and cocaine users. Disparate patterns of polydrug use require careful measurement and analysis to inform targeted treatment for polydrug users.     

Rapid simultaneous determination of ephedrines, amphetamines, cocaine, cocaine metabolites, and opiates in human urine by GC-MS

This paper presents a simple and sensitive chromatographic procedure for the simultaneous determination and quantification of ephedrines, amphetamines, cocaine, cocaine metabolites, and opiates in human urine by gas chromatography-mass spectrometry. This method involves enzyme hydrolysis in the presence of a deuterated internal standard, liquid-liquid extraction, and derivatization with pentafluoropropionic anhydride and pentafluoropropanol. The recovery of each compound averaged at 65.8% or more. The limits of detection determined for each compound by using a 2-mL sample volume ranged from 5 to 50 ng/mL. The calibration curves were linear to 100 ng/mL for all compounds when determined using methamphetamine-d4 and MDMA-d5 as internal standards. This method was successfully applied for the analysis of urine samples suspected to contain intoxicants such as methamphetamine and heroin.     

Associations between behavioral disinhibition and cocaine use history in individuals with cocaine dependence

Background

Behavioral disinhibition has been suggested as both a cause and consequence of substance use disorders. Many studies examining associations between behavioral disinhibition and substance use history have focused on individuals with alcohol dependence or non-dependent college students. In the present study, the relationship between behavioral disinhibition and cocaine use history in individuals with cocaine dependence is examined.

Methods

Forty-six non-treatment-seeking cocaine-dependent men and women completed impulsivity (Barratt Impulsiveness Scale; BIS) and novelty seeking (Temperament and Character Inventory; TCI) questionnaires at the baseline visit of an ongoing study. Unadjusted, and adjusted for gender and age, Pearson correlations were calculated between BIS, TCI, and cocaine use variables from the Structured Clinical Interview for DSM-IV and Timeline Follow-back (age of onset, quantity/frequency of past 30 day cocaine use).

Results

As expected, elevated motor impulsivity and novelty seeking were each associated with younger age of dependence onset. Also, individuals with lower levels of persistence on the TCI reported more days of cocaine use over the previous month. Unexpectedly, increased novelty seeking and attentional impulsivity were associated with fewer days of cocaine use and less money spent on cocaine, respectively. Controlling for age and gender did not substantially change the pattern of observed associations.

Conclusions

The present study provides preliminary evidence for associations between behavioral disinhibition and cocaine use history in cocaine-dependent individuals. Given our relatively small sample size and the correlational nature of our findings, further research is needed to replicate and extend our results.     

Teenagers do not always lie: characteristics and correspondence of telephone and in-person reports of adolescent drug use

Because of the widespread use of drugs by adolescents, there is demand for scientific rigor in sampling and accuracy in methods for ascertaining drug use patterns. The present study: (1) characterized adolescents who responded to advertisements for marijuana users; (2) compared rates of drug use reported on the telephone versus an on-site interview; and (3) examined drug use patterns as a function of parental awareness of drug use. Adolescents, identifying themselves as marijuana users during telephone interviews, reported more use of other drugs than those denying marijuana use. There was a high degree of correspondence between telephone and on-site interviews for all drugs except alcohol, which was reported at a higher rate on-site. Of those reporting marijuana use in the past week, 69% tested positive for marijuana in their urine-drug screens. Finally, marijuana and alcohol use patterns were higher among adolescents whose parents were aware of drug use than those whose parents indicated that their adolescent did not use marijuana. These results indicate that adolescents are willing to self-identify as marijuana users and report drug and alcohol use during telephone interviews. Additionally, parents appear to become more aware of their adolescent's drug use with increased frequency of use.     

Daily stressor sensitivity, abuse effects, and cocaine use in cocaine dependence

This study highlights respondent sensitivity to daily hassles as it relates to situational cocaine use and perceived long-term effects of adverse events in childhood. Data were drawn from a larger study on stress reactivity in cocaine dependent individuals. Participants (n=104) were cocaine dependent men and women without comorbid posttraumatic stress disorder (PTSD). They completed the Early Trauma Inventory (ETI), the Daily Hassles Scale (DHS), the Inventory of Drug-Taking Situations (IDTS), and the Time-Line Follow-Back (TLFB; for 90 days prior to interview). There were no gender differences in the amount or frequency of cocaine use, although the patterns of use differed between male and female users. Overall, there were some associations in the patterns of cocaine use and sensitivity to daily hassles, particularly the use in response to conflict with others. Early negative life events were positively related to response to daily hassles, but current triggers were more relevant. Reactivity to cocaine cues was related to daily hassle sensitivity among women only. Limitations and implications of the findings are discussed.     

Utility of sweat patch testing for drug use monitoring in outpatient treatment for opiate dependence

We evaluated the utility of sweat testing for monitoring of drug use in outpatient clinical settings and compared sweat toxicology with urine toxicology and self-reported drug use during a randomized clinical trial of the efficacy of buprenorphine for treatment of opioid dependence in primary care settings. All study participants (N = 63) were opiate-dependent, treatment-seeking volunteers. The results based on toxicology tests obtained from 188 properly worn and unadulterated patches (out of 536 applied) show that the level of agreement between positive sweat test results and positive urine results was 33% for opiates and 92% for cocaine. The findings of this study, that there is a low acceptability of sweat patch testing by patients (only 54.3% were brought back attached to the skin) and that weekly sweat testing is less sensitive than weekly urine testing in detecting opiate use, suggest limited utility of sweat patch testing in outpatient clinical settings.     

宫内暴露于可卡因的仔鼠脑功能的可塑性研究

目的：建立妊娠中晚期接触可卡因的小鼠动物模型，探讨脑功能的可塑性现象和机制。方法：测量可卡因处理组与对照组仔代小鼠在青春期和成年期的体重与脑重；运用高效液相色谱结合电化学检测器技术（High porformance liquid chromatography-electochemistry,HPLC-EC)检测各仔鼠各时期脑内多巴胺（dopamine,DA)及其代谢产物3，4－双羟苯乙酸（3，4－dihydroxyphenylacetic acid,DOPAC)、高香草酸（4-hydroxy-3-menthoxyphenylacetic acid,HVA)的含量，同时检测各时期仔鼠再次接触可卡因脑内DA、DOPAC和HVA的变化。结果：有可卡因宫内接触史的仔鼠在青春期体重和脑重比对照组仔鼠下降，脑内DA及其代谢产物含量增高，上述变化在成年期恢复正常。各组仔鼠在生后青春期再次接触可卡因后DA及其代谢产物含量均升高，此时可卡因处理组仍比对照组含量高，在成年期各组仔鼠再次接触可卡因虽DA及其代谢产物虽也升高，但无组间差异。结论：妊娠中晚期暴露于可卡因可以引起仔鼠脑多巴胺能神经系统功能的改变，这种改变随脑发育的不断完善而正常，即具有可塑性，并且这种塑性同样适用于静息和应激两种状态下。     

Pathways between ecstasy initiation and other drug use

This study aims to shed light on drug use pathways associated with ecstasy use initiation. Data from 54,573 respondents aged 12-21 years old from the 2002-2003 National Survey on Drug Use and Health (NSDUH) public use data files were analyzed via Cox proportional hazards models with time-dependent covariates. Our findings showed that marijuana, cocaine, and heroin were significant independent predictors of subsequent ecstasy use. Earlier ecstasy initiation was significantly associated with subsequent other illegal drug initiation (marijuana, cocaine and heroin). The strength of the association was greater for the pathway from earlier marijuana initiation to subsequent ecstasy initiation as compared to the pathway in the opposite direction. The pathway from earlier ecstasy initiation to subsequent cocaine and heroin initiation was also stronger as compared to pathways in the opposite directions. Pathways between ecstasy initiation and marijuana, cocaine and heroin initiation seem to be independent of the association between drug use and psychiatric symptoms/deviant behaviors. Ecstasy initiation seems to play a role in the subsequent initiation of cocaine and heroin.     

Responsiveness to cocaine challenge in adult rats following prenatal exposure to cocaine

Adult rats that were gestationally exposed to cocaine and control offspring were examined for their sensitivity to challenge doses of cocaine. Offspring were derived from Sprague-Dawley dams that had received subcutaneous injections of 40 mg/kg per 3 cc cocaine hydrochloride daily on gestational days 8–20, pair-fed dams that were injected with saline, and nontreated control dams. In order to investigate the sensitivity to challenge doses of cocaine, offspring were assessed in adulthood for locomotor activity, cocaine drug discrimination, and the time course of cocaine in brain tissue following acute cocaine challenge. Adult offspring prenatally exposed to cocaine were observed to exhibit a reduced sensitivity to the discriminative stimulus effects of cocaine as evidenced by a significant shift to the right in the dose-response curve of cocaine discrimination. No prenatal treatment effects were observed in terms of the temporal patterns of cocaine discrimination or with regard to brain levels of cocaine. In addition, baseline locomotor activity and locomotor responses to challenge doses of cocaine were comparable across the prenatal treatment groups. Thus, prenatal cocaine exposure reduced sensitivity of offspring to the discriminative stimulus properties of cocaine without altering either the distribution of cocaine to the brain or the sensitivity of the offspring to the locomotor stimulant effects of cocaine.     

Contributions of prolonged contingent and noncontingent cocaine exposure to enhanced reinstatement of cocaine seeking in rats

Rationale Recent evidence suggests that prolonged cocaine self-administration produces escalation in drug-seeking behavior in rats analogous to the increased intake patterns observed in cocaine-dependent individuals. However, the contributions of prolonged access to cocaine taking vs the pharmacologic effects of the consequent increased cocaine exposure on escalation of drug-seeking behaviors have not been investigated.Objective The present study assessed the effects of these two factors on maintenance of cocaine self-administration and reinstatement of cocaine seeking.Methods Male, Sprague–Dawley rats were trained to self-administer cocaine (0.2 mg/i.v. infusion; FR1) for 1 h per day for 10 sessions followed by short access (1 h/day), contingent long access (6 h/day), or noncontingent long access (1 h contingent + 5 h of yoked cocaine infusions/day; i.e., short access + yoked) to cocaine for 14 daily sessions. All rats underwent extinction training and were subsequently tested for the ability of cocaine-paired cues or a cocaine-priming injection (7.5 mg/kg i.p.) to reinstate extinguished cocaine seeking.Results Rats in all groups maintained stable responding for cocaine reinforcement and subsequently showed significant reinstatement of cocaine-seeking behavior. Conditioned-cued reinstatement was enhanced after the contingent long access and short access + yoked cocaine exposure relative to short access cocaine exposure. Conversely, cocaine-primed reinstatement was enhanced after contingent long-access cocaine exposure relative to the other two conditions.Conclusions Enhanced drug seeking produced by prolonged daily cocaine self-administration is due to a combination of behavioral and pharmacological factors. Specifically, conditioned-cued reinstatement is enhanced by increased cocaine intake and cocaine-primed reinstatement is enhanced by increased cocaine taking.     

Underreporting of illicit drug use by patients at emergency departments as revealed by two-tiered urinalysis

This study investigates the validity of questionnaire-based self-reports of illicit drug use by comparing with a two-tiered urinalysis among patients at emergency departments. Questions on the use of alcohol and drugs were administered to patients recruited on a continual basis for 2weeks at the emergency department of two hospitals in northern Taiwan. Positive tests of initial urinalysis using fluorescence polarization immunoassay were further confirmed by gas chromatography/mass spectrometry. In a total of 1502 patients interviewed, 632 (42%) also provided a urine sample. Among those with urine samples, the positive rate of urinalysis was 1.4% for amphetamine-type drugs and 1.6% for opiates. Among those with positive urinalysis, a false-negative rate ranged from 66.6% for amphetamines to 70.0% for opiates. Meanwhile, all the self-reported current uses of either amphetamines or opiates were confirmed by urinalysis. The results indicate that the false-negative rates of questionnaire-based, self-reported current use of illicit drug are around two thirds and the false-positive rates are negligible, which might be useful for the calibration of estimates from epidemiological surveys.