Heavy Cocaine Use Research Articles

Episodic Cocaine Use as a Cause of Venous Thromboembolism and Acute Liver Injury.

BACKGROUND Pulmonary embolism secondary to deep vein thrombosis (DVT) with cor pulmonale is commonly associated with risk factors including surgery, cancer, and prolonged immobility. Cocaine is known to cause vasoconstriction and has a prothrombotic effect. Prolonged and heavy use of cocaine can also cause inflammation and liver damage. However, data on its potential role in causing pulmonary embolism and direct hepatotoxicity in cases of episodic use are scarce. CASE REPORT A 34-year-old man with no significant medical history except for episodic cocaine use presented in respiratory distress. Workup revealed submassive pulmonary embolism with pulmonary infarctions complicated by pneumonia, hypoxemic respiratory failure, and anemia. He was treated with anticoagulation and intensive care. On day 5 of hospitalization, the patient had an acute hepatic injury. His alanine aminotransferase level peaked at over 2000 IU/L on day 7, until finally tapering. Liver failure was found to be secondary to cocaine use. Liver enzyme levels improved with supportive care. He was discharged with apixaban and continued liver enzyme monitoring. CONCLUSIONS When investigating the cause of venous thromboembolism and transaminitis, evaluating cocaine use via patient history or laboratory analysis of cocaine and its metabolites should be considered. Cocaine is known to cause vasoconstriction and has a prothrombotic effect, although data on its potential role in causing pulmonary embolism and direct hepatotoxicity in cases of episodic use are scarce. Further investigation, such as cohort studies, could help strengthen our understanding of the relationship between cocaine use, acute hepatic injury, and pulmonary embolism.

Cocaine-induced behavioral sensitization is greater in adolescent than in adult mice and heightens cocaine-induced conditioned place preference in adolescents

Adolescents are more sensitive than adults to the neural and behavioral effects of psychostimulants, and exhibit greater vulnerability to drug abuse, dependence or relapse into these conditions. We have reported that cocaine pretreatment during adolescence promotes the expression of behavioral sensitization to a greater extent than when the pretreatment occurs at adulthood. Behavioral sensitization has been associated to the transition from drug use to addiction and is postulated to indicate heightened sensitivity to the appetitive motivational effects of drugs. The relationship between behavioral sensitization and conventional measures of drug reward, such as conditioned place preference (CPP), has yet to be thoroughly investigated, and little is known about age-related differences in this phenomenon. The present study tested cocaine-induced CPP in adolescent and adult mice exposed to cocaine (or vehicle) pretreatment, either in an intermittent or “binge” (i.e., heavy cocaine use on a single occasion, which increases the likelihood of experiencing cocaine-related problems) fashion. Cocaine administration induced behavioral sensitization to a greater extent in adolescent than in adult mice. Cocaine-induced CPP was fairly similar in vehicle pretreated adolescent and adult mice, yet greater in adolescent vs. adults after cocaine-induced sensitization. The results confirmed the higher sensitivity of adolescent mice to cocaine-induced behavioral sensitization and suggest its association with greater sensitivity to cocaine's rewarding effects.

Semen Parameters: A Review

The World Health Organization (WHO) provides guidelines for assessing the various semen variables. Semen analysis is one of the most important predictive values of male infertility. Semen consists of spermatozoa suspended in a fluid medium referred to as seminal plasma. This review describe Semen parameters which include appearance (color), volume, pH, motility, morphology, viability, concentration, liquefaction, viscosity, presence of WBC and fructose level. These parameters have been found to be important determinant of functional competence of the spermatozoa. More than 90% of male infertility cases are due to low sperm counts, poor sperm quality and sperm abnormalities caused by a range of factors, including congenital birth defects, diseases, chemical exposure, and lifestyle/habits. Others includes environmental pollutants, exposure to high heat for prolonged periods, heavy use of alcohol, marijuana, or cocaine, smoking, hormone deficiency, infections of the testes or epididymis, older age, previous chemotherapy, previous scarring due to infection, trauma, or surgery, radiation exposure, retrograde ejaculation, use of prescribed drugs.

Committing Economic Crime for Drug Money

We examine the effects of the type and frequency of drug use on whether offenders engage in economic crime to obtain money for drugs. Analyses are based on a nationally representative sample of prison inmates (5,371 property offenders and 4,588 drug offenders). Daily users of heroin, crack cocaine, or powdered cocaine are most likely to report that they committed their offense for drug money. However, offenders who used these drugs less frequently and daily users of marijuana and methamphetamine reported this motivation as well. The motivation was more common among offenders who lacked access to legitimate income. The findings suggest that economic crimes are used to support recreational drug use as well as heavy use of heroin and cocaine.

Neuropsychological Consequences of Chronic Drug Use: Relevance to Treatment Approaches.

Heavy use of drugs impacts of the daily activities of individuals in these activities. Several groups of investigators have indeed documented changes in cognitive performance by individuals who have a long history of chronic drug use. In the case of marijuana, a wealth of information suggests that heavy long-term use of the drug may have neurobehavioral consequences in some individuals. In humans, heavy cocaine use is accompanied by neuropathological changes that might serve as substrates for cognitive dysfunctions. Similarly, methamphetamine users suffer from cognitive abnormalities that may be consequent to alterations in structures and functions. Here, we detail the evidence for these neuropsychological consequences. The review suggests that improving the care of our patients will necessarily depend on the better characterization of drug-induced cognitive phenotypes because they might inform the development of better pharmacological and behavioral interventions, with the goal of improving cognitive functions in these subsets of drug users.

Norcocaine and cocaethylene distribution patterns in hair samples from light, moderate, and heavy cocaine users.

Even though hair analysis often seems to be the best choice for retrospective monitoring of cocaine intake, differentiating between incorporated cocaine and external contamination is widely debated. In this study we report results obtained in 90 hair samples from addicts. All samples were analyzed for cocaine, benzoylecgonine, norcocaine, cocaethylene, and tropococaine by gas chromatography‐mass spectrometry (GC‐MS) techniques coupled with direct immersion solid‐phase micro‐extraction. Cocaine concentrations were stratified into three classes of usage: light (0.5–3 ng/mg), moderate (3.1–10 ng/mg) and heavy (10.1–40 ng/mg). The Substance Abuse and Mental Health Services Administration cut‐off criteria for establishing active cocaine use were applied to the results. For all samples criteria were cocaine levels above 0.5 ng/mg (ranging from 1.63 to 39.29 ng/mg, mean 9.49 ng/mg), benzoylecgonine concentrations ≥ 0.05 ng/mg (ranging from 0.19 to 5.77 ng/mg, mean 1.40), and benzoylecgonine to cocaine % ratio ≥5% (from 6.43 to 26.09%). Norcocaine was present in 58.9% of samples (concentration range: 0.22–3.14 ng/mg) and was strongly predictive only of heavy cocaine use (sensitivity 100% for cocaine concentrations above 9.58 ng/mg). Twenty hair samples from moderate and heavy users tested positive for cocaethylene (concentration range: 0.22–1.98 ng/mg, mean 0.73 ng/mg). This study on hair samples with no chance of false positive cases highlights the very limited applications of testing minor cocaine metabolites for definitive proof of active cocaine consumption. © 2015 The Authors. Drug Testing and Analysis Published by John Wiley & Sons, Ltd.

Refining multivariate disease phenotypes for high chip heritability.

BackgroundStatistical genetics shows that the success of both genetic association studies and genomic prediction methods is positively associated with the heritability of the trait used in the analysis. Identifying highly heritable components of a complex disease can thus enhance genetic studies of the disease. Existing heritable component analysis methods use data from related individuals to compute linearly-combined traits to maximize heritability. Recent advances in acquiring genome-wide markers have enhanced heritability estimation using genotypic data from apparently unrelated individuals, which is referred to as the chip heritability. Novel statistical models are thus needed to identify disease components (subtypes) with high chip heritability.MethodsWe propose an optimization approach to identify highly heritable components of a complex disease as a function of multiple clinical variables. The heritability of the components is estimated directly from unrelated individuals using their genome-wide single nucleotide polymorphisms. The proposed approach can also model the fixed effects due to covariates, such as age and race, so that the derived traits have high chip heritability after correcting for fixed effects. A new sequential quadratic programming algorithm is developed to efficiently solve the proposed optimization problem.ResultsThe proposed algorithm was validated both in simulations and the analysis of a real-world dataset that was aggregated from genetic studies of cocaine, opoid, and alcohol dependence. Simulation studies demonstrated that the proposed approach could identify the hypothesized component from multiple synthesized features. A case study on cocaine dependence (CD) identified a quantitative trait that achieved chip heritability of 0.86 estimated using a cross-validation process. This quantitative trait corresponded to the likelihood of an individual's membership in a CD subtype. Clinical analysis showed that the subtype enclosed individuals who reported heavy use of cocaine but few withdrawal symptoms.ConclusionsExtensive experiments on both synthetic and real-world data demonstrate the effectiveness of the proposed approach as a means to find meaningful disease components with high chip heritability.

Norcocaine in human hair as a biomarker of heavy cocaine use in a high risk population

In hair analysis, cocaine (COC) and its metabolites have been studied relatively extensively with a consistent focus of distinguishing active drug use and excluding external contamination. Although quantitative cut-offs using major metabolite, benzolecgonine (BE), in hair have been proposed to distinguish likely active use from passive exposure, exogenously formed BE may result in false positive tests. Hence, the presence of less commonly detected COC metabolite, norcocaine (NCOC), may be useful in increasing certainty of illicit COC use and evaluating likelihood of environmental contamination. The objective of the present study was to observe the pattern of NCOC detection in a clinical population of suspected users and evaluate the possible role of NCOC in distinguishing systemic exposure from external contamination to COC and assessing intensity of cocaine use. Hair samples collected between January 2011 and May 2013 from the Motherisk Laboratory were analyzed by GC–MS for the presence of COC, BE, and NCOC. NCOC positivity rates (%) for various COC concentration ranges as well as sensitivity, specificity, positive predictive value, and negative predictive values of NCOC as a biomarker of different COC use profiles was calculated. The rate of NCOC positivity (%) within COC concentration ranges (ng/mg) 0.13–0.4 (above LOD, below LOQ), 0.4–3, 3–6, 6–10, 10–14, >14 were 0.26, 4.15, 29.63, 55.85, 80.37, and 94.02, respectively; p<0.0001 for all positivity comparisons between ranges. These results were used to determine a COC cut-off concentration for differing levels of COC use. The presence of NCOC above the LOD of 0.13ng/mg predicted COC concentrations exceeding 14.00ng/mg, with sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 94.0%, 87.9%, 41.5%, and 99.4%, respectively. The presence NCOC above the LOD of 0.13ng/mg predicted COC concentrations exceeding the 75th percentile, with sensitivity, specificity, PPV, and NPV of 76.6%, 94.7%, 74.7%, and 95.2%, respectively. Despite an inability to definitively rule out external contamination, the presence of NCOC in hair is strongly associated with elevated COC levels and performs as a highly specific surrogate marker for frequent/intensive cocaine use and highly sensitive marker for intensive/daily use of cocaine.

Comparing the utility of homogeneous subtypes of cocaine use and related behaviors with DSM‐IV cocaine dependence as traits for genetic association analysis

Because DSM-IV cocaine dependence (CD) is heterogeneous, it is not an optimal phenotype to identify genetic variation contributing to risk for cocaine use and related behaviors (CRBs). We used a cluster analytic method to differentiate homogeneous, highly heritable subtypes of CRBs and to compare their utility with that of the DSM-IV CD as traits for genetic association analysis. Clinical features of CRBs and co-occurring disorders were obtained via a poly-diagnostic interview administered to 9,965 participants in genetic studies of substance dependence. A subsample of subjects (N = 3,443) were genotyped for 1,350 single nucleotide polymorphisms (SNPs) selected from 130 candidate genes related to addiction. Cluster analysis of clinical features of the sample yielded five subgroups, two of which were characterized by heavy cocaine use and high heritability: a heavy cocaine use, infrequent intravenous injection group and an early-onset, heavy cocaine use, high comorbidity group. The utility of these traits was compared with the CD diagnosis through association testing of 2,320 affected subjects and 480 cocaine-exposed controls. Analyses examined both single SNP (main) and SNP-SNP interaction (epistatic) effects, separately for African-Americans and European-Americans. The two derived subtypes showed more significant P values for 6 of 8 main effects and 7 of 8 epistatic effects. Variants in the CLOCK gene were significantly associated with the heavy cocaine use, infrequent intravenous injection group, but not with the DSM-IV diagnosis of CD. These results support the utility of subtypes based on CRBs to detect risk variants for cocaine addiction.

Benzodiazepine dependence among multidrug users in the club scene

BackgroundBenzodiazepines (BZs) are among the most frequently prescribed drugs with the potential for abuse. Young adults ages 18–29 report the highest rates of BZ misuse in the United States. The majority of club drug users are also in this age group, and BZ misuse is prevalent in the nightclub scene. BZ dependence, however, is not well documented. This paper examines BZ dependence and its correlates among multidrug users in South Florida's nightclub scene. MethodsData were drawn from structured interviews with men and women (N=521) who reported regular attendance at large dance clubs and recent use of both club drugs and BZs. ResultsPrevalences of BZ-related problems were 7.9% for BZ dependence, 22.6% BZ abuse, and 25% BZ abuse and/or dependence. In bivariate logistic regression models, heavy cocaine use (OR 2.27; 95% CI 1.18, 4.38), severe mental distress (OR 2.63; 95% CI 1.33, 5.21), and childhood victimization history (OR 2.43; 95% CI 1.10, 5.38) were associated with BZ dependence. Heavy cocaine use (OR 2.14; 95% CI 1.10, 4.18) and severe mental distress (OR 2.16; 95% CI 1.07, 4.37) survived as predictors in the multivariate model. DiscussionBZ misuse is widespread among multidrug users in the club scene, who also exhibit high levels of other health and social problems. BZ dependence appears to be more prevalent in this sample than in other populations described in the literature. Recommendations for intervention and additional research are described.

P01-51-Impulsivity and decision making measured in cocaine addicts in France

IntroductionImpulsivity and decision making are impaired in cocaine addicts. However, most studies were performed in the USA.ObjectivesTo assess impulsivity and decision making in a sample of French cocaine addicts.MethodsSubjects40 current cocaine addicts and 21 control subjects with no history of drug abuse were compared using the Barratt Impulsiveness Scale (BIS) and Iowa Gambling Task (IGT). Subjects from the cocaine addicted group were evaluated for cocaine craving with the Obessive Compulsive Cocaine Scale (OCCS), and for their pattern of use. Statistical analysis: The mean scores of impulsivity and decision making were compared in the two groups (Mann-Whitney U test). In the group of 40 cocaine addicts, clinical factors that could be associated with high impulsivity and poor decision making scores were tested (Spearman’ s rho, Chi-square and Mann-Whitney U tests).ResultCompared to controls, cocaine addicts had a higher impulsivity score (BIS: 72 ± 11 vs 57 ± 8, U = 138, p &lt; .001) and had more disadvantageous choices on the decision making test (IGT) (advantageous minus disadvantageous choices -4 ± 19 vs 24 ± 35, U = 234, p = .005). There was a significant correlation between high impulsivity scores on the BIS and high cocaine craving as well as heavy cocaine use (more than 4 times a week). No correlation was found between poor decision making and high craving or frequent cocaine use.DiscussionThe discrepancy between impulsivity and poor decision making in cocaine addicts is discussed.

Advisor-Teller Money Manager (ATM) Therapy for Substance Use Disorders

Patients with concomitant psychiatric and substance use disorders are commonly assigned representative payees or case managers to help manage their funds, but money management has not been conceptualized as a theory-based treatment. This randomized clinical trial was conducted to determine the effect of a money management-based therapy, advisor-teller money manager (ATM), on substance abuse or dependence. Ninety patients at a community mental health center who had a history of cocaine or alcohol abuse or dependence were assessed after random assignment to 36 weeks of ATM (N=47) or a control condition in which use of a financial workbook was reviewed (N=43). Patients assigned to ATM were encouraged to deposit their funds into a third-party account, plan weekly expenditures, and negotiate monthly budgets. Substance use calendars and urine toxicology tests were collected every other week for 36 weeks and again 52 weeks after randomization. Patients assigned to ATM had significantly more negative toxicologies for cocaine metabolite over time than patients in the control group, and treating clinicians rated ATM patients as significantly more likely to be abstinent from illicit drugs. Self-reported abstinence from alcohol did not significantly differ between groups. Unexpectedly, patients assigned to ATM were more likely to be assigned a representative payee or a conservator than control participants during the follow-up period (ten of 47 versus two of 43). One patient in ATM assaulted the therapist when his check had not arrived. ATM is an efficacious therapy for the treatment of cocaine abuse or dependence among people with concomitant psychiatric illness but requires protection of patient autonomy and staff safety.

Advisor-Teller Money Manager (ATM) Therapy for Substance Use Disorders

Advisor-Teller Money Manager (ATM) Therapy for Substance Use Disorders

Hard drug use in Norway

E.J. Amundsen &amp; A. Bretteville-Jensen: Hard drug use in Norway Background Hard drug use has a variety of heavy personal, social and economic costs. Knowing the size of the hard drug use population, the types of drugs consumed and modes of consumption can help policy makers design better policies and facilitate decision making. Intravenous drug users constitute one subgroup of hard drug users. The aim of this article is to describe 1) how the prevalence of intravenous drug use is estimated in Norway and 2) how available data sources give insight about other types of hard drug use even though we can not estimate the true extent of such use. Some policy consequences are outlined. Methods/Materials Overdose deaths and the mortality multiplier method were used to estimate the prevalence of intravenous drug users. Other materials were used to supply the picture of hard drug use in Norway. Results/Findings The prevalence of intravenous drug users in Norway increased steadily from the early 1980s, peaked in 2001, decreased until 2003 and then stabilized. Heroin is the substance of choice of most hard drug users in Norway and injection is the preferred means of intake. Amphetamines are also injected or consumed in other ways, while heavy use of cocaine in the treatment population is low. The use of more than one substance is common. Conclusion Preventing and reducing heroin injection is the main challenge facing Norwegian policy makers. Other drugs pose a problem as well. Wide availability of substitution treatment has a successful record of helping many former heroin users avoid heroin. The risk of relapsing remains high, however, and of dying after drop out or completion. Current knowledge of hard drug use is fragmented and improved monitoring of this high risk group should be prioritized.

The cost of future problem drug use associated with young people’s behaviors and circumstances

The UK Drug Strategy includes the objective of preventing young people from becoming drug misusers. It is the use of heroin, crack and heavy use of cocaine that accounts for most of the costs associated with drug use. However, research on the efficiency of young people’s interventions at reducing such problem drug use is limited by the expense associated with long-term evaluations. An alternative to undertaking expensive long-term research is to model the probable longer-term problem drug use associated with young people’s behavior and circumstances. This paper estimates the economic cost of future problem drug use associated with young people’s behavior and circumstances, such as their cannabis, cigarette and alcohol use, delinquency and the drug use of their parents and peers.

Association of psychiatric and substance use disorder comorbidity with cocaine dependence severity and treatment utilization in cocaine-dependent individuals

The relations among psychiatric and substance dependence disorders and treatment utilization are of interest both for their clinical management and for health services. We examined these relations using six self-reported indices of cocaine dependence severity and three self-reported measures of treatment utilization and self-help group participation for cocaine dependence. The sample consisted of dyads: namely, a cocaine-dependent adult proband (N=449) and a cocaine-dependent sibling (N=449). Psychiatric and substance use disorders were assessed with the Semi-structured Assessment for Drug Dependence and Alcoholism. We controlled for the nesting within families of proband-sibling dyads and for demographic features using generalized estimating equation linear and logistic regression analyses. We found that psychiatric disorders were associated with an increased likelihood of cocaine dependence treatment or self-help group participation, but with only one of six indices of cocaine dependence severity. Bipolar disorder and antisocial personality disorder were associated with greater past heavy cocaine use, and with utilizing self-help but not treatment. Major depressive disorder and posttraumatic stress disorder were associated with treatment utilization and overall services utilization, respectively. The presence of other substance use disorders (SUDs) was the strongest correlate of cocaine dependence severity. Results suggest that co-occurring substance dependence and psychiatric disorders warrant attention in cocaine dependence assessment, treatment, and self-help.

Effects of perceived cocaine availability on subjective and objective responses to the drug

RationaleSeveral lines of evidence suggest that cocaine expectancy and craving are two related phenomena. The present study assessed this potential link by contrasting reactions to varying degrees of the drug's perceived availability.MethodNon-treatment seeking individuals with cocaine dependence were administered an intravenous bolus of cocaine (0.2 mg/kg) under 100% ('unblinded'; N = 33) and 33% ('blinded'; N = 12) probability conditions for the delivery of drug. Subjective ratings of craving, high, rush and low along with heart rate and blood pressure measurements were collected at baseline and every minute for 20 minutes following the infusions.ResultsCompared to the 'blinded' subjects, their 'unblinded' counterparts had similar craving scores on a multidimensional assessment several hours before the infusion, but reported higher craving levels on a more proximal evaluation, immediately prior to the receipt of cocaine. Furthermore, the 'unblinded' subjects displayed a more rapid onset of high and rush cocaine responses along with significantly higher cocaine-induced heart rate elevations.ConclusionThese results support the hypothesis that cocaine expectancy modulates subjective and objective responses to the drug. Provided the important public health policy implications of heavy cocaine use, health policy makers and clinicians alike may favor cocaine craving assessments performed in the settings with access to the drug rather than in more neutral environments as a more meaningful marker of disease staging and assignment to the proper level of care.

Association between Early Onset of Cigarette, Alcohol and Cannabis Use and Later Drug Use Patterns: An Analysis of a Survey in European Metropolises

Objectives: The study presents data about age of onset of alcohol, cigarette and cannabis use and investigates the association between age of onset and later drug use patterns. Methods: Using a sample from a cross-sectional multi-site study, personal interviews were conducted with 3,503 individuals aged 12–49 years. Last-month prevalence, age of onset and associations with subsequent use patterns were investigated. Results: Having started with cannabis before the age of 16 years was associated with an odds ratio of 1.6 for heavy cannabis use. For males, the odds ratio of heavy cannabis use was 1.7, when cannabis was already initiated by the age of 16. Heavy use of ecstasy, amphetamines, hallucinogens and cocaine is associated with use of cigarettes before 13 (OR = 1.9). For males, the odds ratio was 2.2 and for women 1.9. Conclusions: Early use of alcohol, according to this data, does not seem to be related to subsequent heavy drug use. Early onset cannabis users show increasing probabilities of heavy use patterns. Preventive intervention programs have to start earlier than school-based programs normally do and specific developmental pathways need to be addressed.

Predictors of motor development in children prenatally exposed to cocaine

The current study examined the pattern of motor development across the first 18 months of life in infants with in utero exposure to cocaine to determine how prenatal drug effects and level of exposure relates to motor development. Motor development was examined at 1, 4, 12, and 18 months of age (corrected for prematurity). Infants were divided into cocaine exposed ( n=392) and comparison ( n=776) groups. Exposure status was determined by meconium assay and maternal self-report with alcohol, marijuana, tobacco, and opiates present in both groups. Motor skills were assessed at 1 month using the NICU Network Neurobehavioral Scale (NNNS), at 4 months using the posture and fine motor assessment of infants (PFMAI), at 12 months using the Bayley Scales of Infant Development-Second Edition (BSID-II), and at 18 months using the Peabody Developmental Motor Scales (PDMS). Examiners masked to exposure status performed all assessments. Motor scores were converted to standard ( z) scores, and hierarchical linear modeling (HLM) was used to examine the change in motor skills from 1 to 18 months of age. Infants with exposure to cocaine showed low motor skills at their initial status of 1 month but displayed significant increases over time. Both higher and lower levels of tobacco use related to poorer motor performance on average. Heavy cocaine use related to poorer motor performance as compared to no use, but there were no effects of level of cocaine use on change in motor skills.

The National Treatment Outcome Research Study (NTORS): 4-5 year follow-up results.

The National Treatment Outcome Research Study (NTORS) is the first prospective national study of treatment outcome among drug misusers in the United Kingdom. NTORS investigates outcomes for drug misusers treated in existing services in residential and community settings. The study used a longitudinal, prospective cohort design. Data were collected by structured interviews at intake to treatment, 1 year, 2 years and at 4-5 years. The sample comprised 418 patients from 54 agencies and four treatment modalities. Measures were taken of illicit drug use, injecting and sharing injecting equipment, alcohol use, psychological health and crime. Rates of abstinence from illicit drugs increased after treatment among patients from both residential and community (methadone) programmes. Reductions were found for frequency of use of heroin, non-prescribed methadone, benzodiazepines, injecting and sharing of injecting equipment. For most variables, reductions were evident at 1 year with outcomes remaining at about the 1 year level or with further reductions. Crack cocaine and alcohol outcomes at 4-5 years were not significantly different from intake. Substantial reductions across a range of problem behaviours were found 4-5 years after patients were admitted to national treatment programmes delivered under day-to-day conditions. The less satisfactory outcomes for heavy drinking and use of crack cocaine suggest the need for services to be modified to tackle these problems more effectively. Despite differences between the United Kingdom and the United States in patient populations and in treatment programmes, there are many similarities between the two countries in outcomes from large-scale, multi-site studies.