Using a latent variable approach to inform gender and racial/ethnic differences in cocaine dependence: a National Drug Abuse Treatment Clinical Trials Network study

The cultural equivalence of measurement in substance use research

Across a wide range of substance use outcomes, ethnic/racial minorities in the U.S. experience a disproportionately higher burden of negative health outcomes and/or lower levels of access to care (relative to non-Latinx White individuals). Various explanations for these substance use-related health disparities have been proposed. This narrative review will not focus on the theoretical content of these explanations but will instead focus on the underlying statistical frameworks that are used to test such theories. Here, we provide a narrative review of psychometric critiques of cross-cultural research, which collectively suggest that (a) research testing similarities and differences among ethnic/racial groups often miss or omit to test statistical assumptions of equal instrument functioning across the ethnic/racial groups being compared; (b) testing the assumptions of equal instrument functioning is feasible using established guidelines from modern measurement theories; and (c) substance use research may need to explicitly incorporate the tests of equal instrument functioning to prevent bias when making inferences across ethnic/racial groups. We provide recommendations for evaluating the cultural equivalence of measurement using structural equation modeling, and advocate that cross-cultural substance use research move toward statistical approaches that are better positioned to test for (and model) bias in measurement. Explicitly testing the cultural equivalence of measurement when making inferences across cultural groups (within a falsifiable psychometric framework) can advance our understanding of similarities and differences among ethnic/racial groups, and hence can provide a more socially just (and statistically robust) scientific base. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

SNPs from BCHE and DRD3 genes associated to cocaine abuse amongst violent individuals from Sao Paulo, Brazil

Violence and drug abuse are highly destructive phenomena found world-wide, especially in Brazil. They seem to rise proportionally to one another and possibly related. Additionally, genetics may also play a role in drug abuse. This study has focused on identifying the use of cocaine within postmortem cases arriving at the Institute of Legal Medicine of Sao Paulo as well as the presence of certain single nucleotide polymorphisms (SNPs) to better understand one's susceptibility to abuse the drug. Both hair and blood samples have been extracted through a simple methanol overnight incubation or a rapid dilute-and-shoot method, respectively. The samples were then analyzed using an UPLC-ESI-MS/MS and genotyped through RT-PCR. Statistical analyses were performed via SPSS software. From 105 postmortem cases, 53% and 51% of the cases shown to be positive for cocaine in hair and blood, respectively. Genetic wise, a significant difference has been observed for SNP rs4263329 from the BCHE gene with higher frequencies of the genotypes A/G and G/G seen in cocaine users (OR=8.91; 95%CI=1.58-50.21; p=0.01). Likewise, also SNP rs6280 from the DRD3 gene presented a significant association, with both genotypes T/C and C/C being more frequent in users (OR=4.96; 95% CI=1.07-23.02; p=0.04). To conclude, a rather high proportion of cocaine has been found, which may suggest a connotation between the use of the drug and risky/violent behaviors. Additionally, significant associations were also found within two SNPs related to cocaine use, however, due to several inherent limitations, these must be confirmed.

A systematic scoping review of research on Black participants in the National Drug Abuse Treatment Clinical Trials Network

Black individuals experience a disproportionate burden of substance-related disabilities and premature death relative to other racial/ethnic groups, highlighting the need for additional research. The National Drug Abuse Treatment Clinical Trials Network (CTN), a research platform for multisite behavioral, pharmacological, and integrated trials designed to evaluate the effectiveness of substance use treatments in community settings with diversified patient populations, provides a wealth of research knowledge on substance use. Although CTN trials have enrolled over 5,000 Black individuals since its inception in 2000, there has been no synthesis of the findings, discussion of the implications, or suggestions for future research for Black individuals. Members of the Minority Interest Group of the CTN conducted a scoping review of published research on Black participants in CTN trials. Studies were included if the sample was more than 75% Black and/or specific findings pertaining to Black participants were reported. The review yielded 50 articles, with studies that mostly focused on baseline characteristics, followed by substance use treatment outcomes, HIV/risky sex behaviors, retention, comorbid conditions and measurement issues. This review highlighted the importance of several issues that are critical to understanding and treating substance misuse among Black people, such as the characteristics of Black people entering treatment, measurement equivalence, and engaging/retaining adolescents and young adults in treatment. There is still a continued need to identify the most effective treatments for Black individuals who use substances. The CTN offers several untapped opportunities to further advance research on Black individuals who use substances (e.g., secondary analyses of publicly available data). (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Data sharing platforms for de-identified data from human clinical trials

Data sharing of de-identified individual participant data is being adopted by an increasing number of sponsors of human clinical trials. In addition to standardizing data syntax for shared trial data, semantic integration of various data elements is the focus of several initiatives that define research common data elements. This perspective article, in the first part, compares several data sharing platforms for de-identified clinical research data in terms of their size, policies and supported features. In the second part, we use a case study approach to describe in greater detail one data sharing platform (Data Share from National Institute of Drug Abuse). We present data on the past use of the platform, data formats offered, data de-identification approaches and its use of research common data elements. We conclude with a summary of current and expected future trends that facilitate secondary research use of data from completed human clinical trials.

The Prevalence of Posttraumatic Stress Disorder Symptoms among Addiction Treatment Patients with Cocaine Use Disorders

Co-occurring cocaine use and posttraumatic stress disorders are prevalent and associated with negative treatment, health and societal consequences. This study examined the relationships among PTSD symptoms, gender, and cocaine use problems. Within a cross-sectional design, we gathered archival point prevalence data on new admissions (n = 573) to three addiction treatment agencies. Demographic, substance use, and PTSD symptom information were collected across the three agencies. Logistic regression analyses revealed that patients with cocaine use disorders had a two-fold increased odds for a probable PTSD diagnosis, compared to patients without a cocaine use disorder (OR = 2.19, 95% CI = 1.49-3.22, p < 0.001). Among females with cocaine use disorder, multinomial regression yielded a significant increase in the risk of moderate (RRR = 2.12, 95% CI = 1.10-4.10, p < 0.05) and severe (RRR = 2.87, 95% CI = 1.33-6.21, p < 0.01) PTSD symptoms. Males with cocaine use disorders had a two-fold increase in the risk of moderate PTSD symptoms (RRR = 2.13, 95% CI = 1.23-3.68, p < 0.01), but had no increased risk of developing severe PTSD symptoms (RRR = 1.93, 95% CI = 0.85-4.39, p = 0.117). Cocaine use appears to impact the risk of PTSD symptoms, especially in females. Future research should explore the generalizability of these findings to more racially and ethnically diverse samples, as well as among persons with this comorbidity who are not engaged in treatment services.

Sex effects in cocaine-using methadone patients randomized to contingency management interventions

Contingency management (CM) is an effective treatment for promoting cocaine abstinence in patients receiving methadone maintenance. However, few studies have examined the effect of sex on treatment outcomes in this population. This study evaluated the impact of sex on longest duration of abstinence (LDA) and percent negative urine samples in 323 cocaine-using methadone patients from 4 randomized clinical trials comparing CM to standard methadone care. Overall, women had better treatment outcomes compared with men, demonstrated by an increase in both LDA and percentages of negative samples. Patients receiving CM also had significantly higher LDA and percentages of negative samples compared to patients receiving standard care, but sex by treatment condition effects were not significant. These data suggest that cocaine-using methadone patients who are women have better substance use outcomes than men in interventions that regularly monitor cocaine use, and CM is equally efficacious regardless of sex.

Examining the relationship between ethnicity and the use of drug-related services: an ethnographic study of Nepali drug users in Hong Kong

A recent survey has shown that Nepali drug users in Hong Kong tend to have a low rate of usage of day-care and residential rehabilitation services, but a high rate of usage of methadone services. Little is known about the reasons behind such a pattern. Therefore, in this study, a 12-month ethnographic examination has been implemented in three sites, including a day-care center, residential rehabilitation center, and methadone clinic, to explore the experiences of 20 Nepali drug users in their use of drug-related services in Hong Kong and to examine the relationship between ethnicity and the use of drug-related services. The result shows that the reason for this pattern of service use is related to the approach of the services and the cultural perception of the service providers about the service users. The day-care and residential rehabilitation services emphasize an integrated approach, but the staff tend to overlook the heterogeneity of their clients, for example, the differences in caste and sex, and fail to provide suitable services to them, whereas the methadone service follows a biomedical model, which seldom addresses the social characteristics of the service users, which in turn minimizes the opportunity for misunderstandings between the staff and the clients. This research shows that ethnicity is a significant factor in drug treatment and that culture-specific treatment that takes into consideration the treatment approach and the heterogeneity of the clients is strongly needed.

Genetic variation in OPRD1 and the response to treatment for opioid dependence with buprenorphine in European-American females

Two commonly prescribed treatments for opioid addiction are methadone and buprenorphine. While these drugs show some efficacy in treating opioid dependence, treatment response varies among individuals. It is likely that genetic factors play a role in determining treatment outcome. This study analyses the pharmacogenetic association of 6 polymorphisms in OPRD1, the gene encoding the delta-opioid receptor, on treatment outcome in 582 opioid addicted European Americans randomized to either methadone or buprenorphine/naloxone ((Suboxone®) over the course of a 24 week open-label clinical trial. Treatment outcome was assessed as the number of missed or opioid positive urine drug screens over the 24 weeks. In the total sample, no SNPs in OPRD1 were significantly associated with treatment outcome in either treatment arm. However, sex-specific analyses revealed 2 intronic SNPs (rs581111 and rs529520) that predicted treatment outcome in females treated with buprenorphine. Females with the AA or AG genotypes at rs581111 had significantly worse outcomes than those with the GG genotype when treated with buprenorphine (p=0.03, RR=1.67, 95% C.I.[1.06-2.1]). For rs529520, females with the AA genotype had a significantly worse outcome than those with the CC genotype when (p=0.006, RR=2.15, 95%C.I.[1.3-2.29]). No significant associations were detected in males. These findings suggest that rs581111 and rs52920 may be useful when considering treatment options for female opioid addicts, however confirmation in an independent sample is warranted.

The national drug abuse treatment clinical trials network data share project: website design, usage, challenges, and future directions

BACKGROUND

There are many benefits of data sharing, including the promotion of new research from effective use of existing data, replication of findings through re-analysis of pooled data files, meta-analysis using individual patient data, and reinforcement of open scientific inquiry. A randomized controlled trial is considered as the 'gold standard' for establishing treatment effectiveness, but clinical trial research is very costly, and sharing data is an opportunity to expand the investment of the clinical trial beyond its original goals at minimal costs.

PURPOSE

We describe the goals, developments, and usage of the Data Share website (http://www.ctndatashare.org) for the National Drug Abuse Treatment Clinical Trials Network (CTN) in the United States, including lessons learned, limitations, and major revisions, and considerations for future directions to improve data sharing.

METHODS

Data management and programming procedures were conducted to produce uniform and Health Insurance Portability and Accountability Act (HIPAA)-compliant de-identified research data files from the completed trials of the CTN for archiving, managing, and sharing on the Data Share website.

RESULTS

Since its inception in 2006 and through October 2012, nearly 1700 downloads from 27 clinical trials have been accessed from the Data Share website, with the use increasing over the years. Individuals from 31 countries have downloaded data from the website, and there have been at least 13 publications derived from analyzing data through the public Data Share website.

LIMITATIONS

Minimal control over data requests and usage has resulted in little information and lack of control regarding how the data from the website are used. Lack of uniformity in data elements collected across CTN trials has limited cross-study analyses.

CONCLUSIONS

The Data Share website offers researchers easy access to de-identified data files with the goal to promote additional research and identify new findings from completed CTN studies. To maximize the utility of the website, ongoing collaborative efforts are needed to standardize the core measures used for data collection in the CTN studies with the goal to increase their comparability and to facilitate the ability to pool data files for cross-study analyses.

A dimensional approach to understanding severity estimates and risk correlates of marijuana abuse and dependence in adults

While item response theory (IRT) research shows a latent severity trait underlying response patterns of substance abuse and dependence symptoms, little is known about IRT-based severity estimates in relation to clinically relevant measures. In response to increased prevalences of marijuana-related treatment admissions, an elevated level of marijuana potency, and the debate on medical marijuana use, we applied dimensional approaches to understand IRT-based severity estimates for marijuana use disorders (MUDs) and their correlates while simultaneously considering gender- and race/ethnicity-related differential item functioning (DIF). Using adult data from the 2008 National Survey on Drug Use and Health (N = 37,897), Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for MUDs among past-year marijuana users were examined by IRT, logistic regression, and multiple indicators-multiple causes (MIMIC) approaches. Among 6917 marijuana users, 15% met criteria for a MUD; another 24% exhibited subthreshold dependence. Abuse criteria were highly correlated with dependence criteria (correlation = 0.90), indicating unidimensionality; item information curves revealed redundancy in multiple criteria. MIMIC analyses showed that MUD criteria were positively associated with weekly marijuana use, early marijuana use, other substance use disorders, substance abuse treatment, and serious psychological distress. African Americans and Hispanics showed higher levels of MUDs than Whites, even after adjusting for race/ethnicity-related DIF. The redundancy in multiple criteria suggests an opportunity to improve efficiency in measuring symptom-level manifestations by removing low-informative criteria. Elevated rates of MUDs among African Americans and Hispanics require research to elucidate risk factors and improve assessments of MUDs for different racial/ethnic groups.

Alcohol and drug dependence symptom items as brief screeners for substance use disorders: results from the Clinical Trials Network

AIM

To address an urgent need for screening of substance use problems in medical settings, we examined substance-specific dependence criteria as potential brief screeners for the detection of patients with a substance use disorder (SUD).

METHODS

The sample included 920 opioid-dependent adults who were recruited from outpatient treatment settings at 11 programs in 10 U.S. cities and who completed intake assessments of SUDs for a multisite study of the National Drug Abuse Treatment Clinical Trials Network (CTN003). Data were analyzed by factor analysis, item response theory (IRT), sensitivity, and specificity procedures.

RESULTS

Across all substances (alcohol, amphetamines, cannabis, cocaine, sedatives), withdrawal was among the least prevalent symptoms, while taking large amounts and inability to cut down were among the most prevalent symptoms. Items closely related to the latent trait of a SUD showed good-to-high values of area under the receiver operating characteristic curve in identifying cases of a SUD; IRT-defined severe and less discriminative items exhibited low sensitivity in identifying cases of a SUD (withdrawal for all substances; time using for alcohol and sedatives; giving up activities for sedatives).

CONCLUSIONS

Study results suggest that withdrawal and time using are much less reliable indicators for a SUD than taking larger amounts than intended and inability to cut down and that the latter two items should be studied further for consideration in developing a simplified tool for screening patients for SUDs in medical settings. These findings have implications for the use of common health indicators in electronic health records systems to improve patient care.

Use of item response theory and latent class analysis to link poly-substance use disorders with addiction severity, HIV risk, and quality of life among opioid-dependent patients in the Clinical Trials Network

BACKGROUND

This study applied item response theory (IRT) and latent class analysis (LCA) procedures to examine the dimensionality and heterogeneity of comorbid substance use disorders (SUDs) and explored their utility for standard clinical assessments, including the Addiction Severity Index (ASI), HIV Risk Behavior Scale (HRBS), and SF-36 quality-of-life measures.

METHODS

The sample included 343 opioid-dependent patients enrolled in two national multisite studies of the U.S. National Drug Abuse Treatment Clinical Trials Network (CTN001-002). Patients were recruited from inpatient and outpatient addiction treatment settings at 12 programs. Data were analyzed by factor analysis, IRT, LCA, and latent regression procedures.

RESULTS

A two-class LCA model fit dichotomous SUD data empirically better than one-parameter and two-parameter IRT models. LCA distinguished 10% of severe comorbid opioid-dependent individuals who had high rates of all SUDs examined-especially amphetamine and sedative abuse/dependence-from the remaining 90% who had SUDs other than amphetamine and sedative abuse/dependence (entropy=0.99). Item-level results from both one-parameter and two-parameter IRT models also found that amphetamine and sedative abuse/dependence tapped the more severe end of the latent poly-SUD trait. Regardless of whether SUDs were defined as a continuous trait or categorically, individuals characterized by a high level of poly-SUD demonstrated more psychiatric problems and HIV risk behaviors.

CONCLUSIONS

A combined application of categorical and dimensional latent approaches may improve the understanding of comorbid SUDs and their associations with other clinical indicators. Abuse of sedatives and methamphetamine may serve as a useful marker for identifying subsets of opioid-dependent individuals with needs for more intensive interventions.

Conducting research with racial/ethnic minorities: methodological lessons from the NIDA Clinical Trials Network

BACKGROUND

Multiple studies in the National Institute on Drug Abuse Clinical Trials Network (CTN) demonstrate strategies for conducting effective substance abuse treatment research with racial/ethnic minorities (REMs).

OBJECTIVES

The objectives of this article are to describe lessons learned within the CTN to (1) enhance recruitment, retention, and other outcomes; (2) assess measurement equivalence; and (3) use data analytic plans that yield more information.

METHOD

This article includes background information and examples from multiple CTN studies on inclusion, measurement, and data analysis.

RESULTS AND CONCLUSIONS

Seven recommendations are included for conducting more effective research on REMs.

Relationship between gender and psychotic symptoms in cocaine-dependent and methamphetamine-dependent participants

BACKGROUND

It has been well documented that cocaine and methamphetamine use can lead to the onset of psychotic symptoms similar to schizophrenia. However, the research and literature on gender differences and stimulant-induced psychosis have been mixed.

OBJECTIVE

The primary aim of this study was to investigate gender differences in the reporting of psychotic symptoms in cocaine- versus methamphetamine-dependent individuals.

METHODS

Participants were recruited from the Los Angeles, California, community via radio and newspaper advertisements. All met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for cocaine or methamphetamine dependence, and all reported either methamphetamine or cocaine as their primary drug of abuse. During a screening interview, participants answered questions from the Psychotic Symptom Assessment Scale, which characterizes various types of psychotic symptoms during drug use ("while high") or during periods of nonuse ("while abstinent").

RESULTS

Participants included 42 cocaine-dependent individuals (27 men, 15 women) and 43 methamphetamine-dependent individuals (25 men, 18 women). Among cocaine users, there were no significant differences between men and women with regard to ethnicity, years of use, route of administration, and amount used in the past week, though they differed significantly with regard to age (P = 0.029). In the "while abstinent" condition, women were significantly more likely than men to report experiencing auditory hallucinations (13% vs 0%, respectively; P = 0.050) and tactile hallucinations (20% vs 0%; P = 0.016), whereas men were more likely to report delusions of grandeur (48% vs 6%; P = 0.006). During the "while high" condition, women were significantly more likely than men to report delusions of grandeur (13% vs 0%, respectively; P = 0.050), tactile hallucinations (33% vs 0%; P = 0.001), and olfactory hallucinations (13% vs 0%; P = 0.050). Among methamphetamine users, there were no significant differences between men and women with regard to age, ethnicity, years of use, route of administration, or amount used in the past week. In the "while abstinent" condition, women were significantly more likely than men to report feeling that something was wrong with the way a part of their body looked (72% vs 32%, respectively; P = 0.009), olfactory hallucinations (39% vs 8%; P = 0.010) and dressing inappropriately (22% vs 0%; P = 0.010). During the "while high" condition, women were more likely than men to report delusions of grandeur (33% vs 16%, respectively; P = 0.030), paranoia (50% vs 16%; P = 0.017), and tactile hallucinations (61% vs 32%; P = 0.050).

CONCLUSIONS

The findings of the present study revealed that cocaine- and methamphetamine-dependent women were more likely than their male counterparts to report experiencing various psychotic symptoms. This information may be useful for clinicians and mental health professionals, who should take these symptoms into account as potential barriers that may impede effective treatment.

The effects of oral micronized progesterone on smoked cocaine self-administration in women

There are currently no FDA-approved pharmacotherapies for cocaine abuse. Converging preclinical and clinical evidence indicates that progesterone may have potential as a treatment for cocaine-abusing women, who represent a growing portion of cocaine users. We have previously shown that oral progesterone reduced the positive subjective effects of cocaine in female cocaine users during the follicular phase of the menstrual cycle, when endogenous progesterone levels were low. To extend these findings, the present study assessed the effects of oral progesterone (150 mg BID) administered during the follicular phase on smoked cocaine self-administration in women relative to the normal follicular and luteal phases. Healthy, non-treatment seeking female cocaine smokers (N=10) underwent three 4-day inpatient stays, during: 1) a normal follicular phase; 2) a normal luteal phase; and 3) a follicular phase when oral progesterone was administered. During each stay, participants completed 4 self-administration sessions in which they first smoked a "sample" dose of cocaine (0, 12, 25 or 50 mg) and then had 5 opportunities at 14-minute intervals to self-administer that dose at a cost of $5 per dose. Expected cocaine dose effects on self-administration, subjective effects, and cardiovascular effects were observed. However, there was no effect of oral progesterone administration or menstrual cycle phase on cocaine self-administration. Thus, oral progesterone was not effective in reducing cocaine use in women under the current conditions. However, based on previous literature, further research assessing the role of oral progesterone for the treatment of cocaine dependence in women is warranted.