Predicting postdischarge opiate abstinence from admission measures of motivation and confidence.

Admission scores from a model comprising 3 motivation factors concerning the cessation of heroin use and a confidence scale concerning postdischarge abstinence were tested for their ability to predict postdischarge outcomes in patients beginning inpatient opiate detoxification. Statistically significant prediction of abstinence from heroin 30 days after discharge and the number of heroin-free days in the 3 months following admission was based on the confidence scale and a factor concerned with externally imposed constraints on continued heroin use. The single-scale confidence measure made the largest contribution to each prediction, indicating that such scales may be potentially useful outcome predictors for postdischarge abstinence. External constraints on heroin use may not provide a basis for success in this treatment modality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical and Sexual Intimate Partner Violence Among Women in Methadone Maintenance Treatment.

Although several studies have examined the relationship between intimate partner violence (IPV) and drug use among women in drug treatment programs, more information is needed to delineate differences, as a function of the specific drug used. Data from a random sample of 416 women attending methadone programs were analyzed to elucidate the differential associations between IPV and use of the following: marijuana only, cocaine only, heroin only, or cocaine and heroin. Prevalence of IPV among this sample far exceeded estimates from the general population. After adjusting for sociodemographic variables, use of cocaine only was significantly associated with an increased likelihood of experiencing IPV compared with no drug use. Similar results were found for women using both cocaine and heroin. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the nature of the conditioned stimulus: Comment on Leri and Stewart (2002).

F. Leri and J. Stewart (see record 2002-06535-001) present convincing evidence that a relapse to heroin-seeking behavior is established when rats are given a momentary lapse in which they are allowed to respond while under the influence of heroin. Although exposure to a conditioned stimulus (CS) paired with heroin self-infusion did not induce a relapse, it was able to control responding. In addition to serving as both a discriminative stimulus and a conditioned reinforcer, it is argued in this article that the CS also may have positive hedonic value independent of its association with heroin and that this property should be considered in interpreting the results of future experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do animal models provide a valid analogue for human drug lapse and relapse? Comment on Leri and Stewart (2002).

Prior research on animal models of drug relapse has demonstrated that passive exposure to an addictive substance following acquisition and extinction of drug self-administration has a "priming effect" on subsequent drug use. The validity of this animal analogue of human relapse can be criticized, however, because most human drug relapses are precipitated by the user's voluntary self-administration of a substance. The results of the present study by F. Leri and J. Stewart (see record 2002-06535-001) clearly show that if the initial heroin lapse is self-administered by rats, subsequent heroin seeking during the relapse test is significantly greater than if the heroin is externally administered. These results help bridge the gap between animal and human models of drug use and highlight the significance of both behavioral and environmental determinants of relapse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of acute and prolonged opiate abstinence on extinction behaviour in rats.

We examined the role of withdrawal in relapse to drug-seeking and drug-taking by testing the effects of opiate abstinence on extinction behaviour in rats trained to self-administer heroin. Male Long-Evans rats responded for IV heroin under a heterogeneous chain (VI 120 s; FR 1) schedule in which "seeking" responses preceded a "taking" response which produced a drug infusion. Responding was then measured in extinction during acute (6, 12, and 24 hr) and prolonged (3, 6, 12, and 25 day) abstinence. Sucrose consumption and somatic withdrawal were assessed at each testing period. During acute abstinence, responses on the "drug-seeking" manipulandum increased at 24 hr, whereas responses on the "drug-taking" manipulandum increased at 6 hr. Both responses were elevated during the 12-day abstinence test. Sucrose consumption was reduced and somatic withdrawal scores were increased in opiate-experienced rats at each test period. Results suggest that heroin abstinence has different effects on drug-seeking and drug-taking and that these effects do not temporally coincide with somatic measures of opioid withdrawal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Altered Accumbal Dopamine Terminal Dynamics Following Chronic Heroin Self-Administration

Administration of heroin results in the engagement of multiple brain regions and the rewarding and addictive effects are mediated, at least partially, through activation of the mesolimbic dopamine system. However, less is known about dopamine system function following chronic exposure to heroin. Withdrawal from chronic heroin exposure is likely to drive a state of low dopamine in the nucleus accumbens (NAc), as previously observed during withdrawal from other drug classes. Thus, we aimed to investigate alterations in NAc dopamine terminal function following chronic heroin self-administration to identify a mechanism for dopaminergic adaptations. Adult male Long Evans rats were trained to self-administer heroin (0.05 mg/kg/inf, IV) and then placed on a long access (FR1, 6-h, unlimited inf, 0.05 mg/kg/inf) protocol to induce escalation of intake. Following heroin self-administration, rats had decreased basal extracellular levels of dopamine and blunted dopamine response following a heroin challenge (0.1 mg/kg/inf, IV) in the NAc compared to saline controls. FSCV revealed that heroin-exposed rats exhibited reduced stimulated dopamine release during tonic-like, single-pulse stimulations, but increased phasic-like dopamine release during multi-pulse stimulation trains (5 pulses, 5–100 Hz) in addition to an altered dynamic range of release stimulation intensities when compared to controls. Further, we found that presynaptic D3 autoreceptor and kappa-opioid receptor agonist responsivity were increased following heroin self-administration. These results reveal a marked low dopamine state following heroin exposure and suggest the combination of altered dopamine release dynamics may contribute to increased heroin seeking.     

海洛因GC-FID分析方法的色谱条件优化

通过考察流速、分流比、色谱柱升温程序对柱效、保留时间、峰面积等指标的影响规律,对海洛因毒品GC-FID分析方法的色谱条件进行了优化,以使海洛因GC-FID分析方法更好地应用于日常办案。优化的色谱条件为:色谱柱:DB-5石英玻璃毛细管柱(30m×0.32mm×0.25μm);载气:N2,纯度99.99%;进样温度:280℃;流速:1mL·min~-1;分流比:20∶1;升温程序:以150℃为初始柱温,以12℃·min~-1升温至300℃,在300℃保持7min;检测温度:300℃。     

The Addiction Severity Index as a predictor of the use of mental health care.

The Addiction Severity Index (ASI) has been extensively used in the United States and Europe as an indicator of the problems of substance abuse patients. Several studies have shown the ASI to be a reliable and valid instrument, but lately doubt has arisen regarding its validity and reliability. The article focuses on a specific scale of the ASI-the Psychiatric Status scale-and its strength in predicting the use of mental health care. A group of 1,027 heroin patients in Rotterdam, the Netherlands, who participated in a methadone program were the subjects. Three indices have been used: the evaluation index, the clinical index, and the composite scores. It appears that no matter which indices are used, the Psychiatric scale does discriminate between those who will have contact with mental health care and those who will not. However, the percentage of false positives is high. None of the indices predicts the intensity and duration of the mental health care treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single- Versus Dual-Drug Target: Effects in a Brief Abstinence Incentive Procedure.

The number of drugs targeted may have an important influence on the ability of drug abusers to abstain during motivational incentive procedures. The authors investigated outcomes in methadone maintenance patients (n = 58), who had evidence of both opiate and cocaine use, when continuous abstinence from cocaine only (single target) or from both cocaine and heroin (dual target) was required to earn $200 in voucher incentives over a 4-day period. Study patients were equally likely to initiate and sustain abstinence from cocaine under the single- versus the dual-drug target. They were more likely to initiate opiate abstinence under the dual-target condition, demonstrating sensitivity to reinforcer effects. Results suggest that adding a second drug target does not impede short-term cocaine abstinence initiation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A wasting resource: public housing and drug use in inner‐city Melbourne

Public housing is one of few sources of low‐income rental housing in inner‐city Melbourne, Australia. Most of this housing is easily identifiable high‐rise estates. Some of these estates have become established centres of heroin dealing and drug use. This has had significant consequences: applicants reject offers of housing on the estates; tenants apply for transfers; and housing officers face workplace occupational health and safety issues. In sum, the presence of the drug trade is undermining the provision of affordable, well‐located public housing. This paper contributes to discussions that seek to restore the value of this common resource. It does so by drawing on qualitative interviews and focus groups conducted with heroin users who live in and/or use public housing. The experience of these individuals gives insight into the current relationship between the illicit drug trade and public housing, as well as some understanding of the resilience of the illicit drug trade. The paper looks at measures that have been implemented to address this problem, before questioning whether there is room for an innovative, regulatory response to illicit drug use.