Browsing by Author "Woody, George E"
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Item Open Access A dimensional approach to understanding severity estimates and risk correlates of marijuana abuse and dependence in adults.(International journal of methods in psychiatric research, 2012-06) Wu, Li-Tzy; Woody, George E; Yang, Chongming; Pan, Jeng-Jong; Reeve, Bryce B; Blazer, Dan GWhile 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.Item Open Access Alcohol and drug dependence symptom items as brief screeners for substance use disorders: results from the Clinical Trials Network.(Journal of psychiatric research, 2012-03) Wu, Li-Tzy; Blazer, Dan G; Woody, George E; Burchett, Bruce; Yang, Chongming; Pan, Jeng-Jong; Ling, WalterAIM: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.Item Open Access An item response theory modeling of alcohol and marijuana dependences: a National Drug Abuse Treatment Clinical Trials Network study.(Journal of studies on alcohol and drugs, 2009-05) Wu, Li-Tzy; Pan, Jeng-Jong; Blazer, Dan G; Tai, Betty; Stitzer, Maxine L; Brooner, Robert K; Woody, George E; Patkar, Ashwin A; Blaine, Jack DOBJECTIVE:The aim of this study was to examine psychometric properties of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), diagnostics criteria for alcohol and marijuana dependences among 462 alcohol users and 311 marijuana users enrolled in two multisite trials of the National Drug Abuse Treatment Clinical Trials Network. METHOD:Diagnostic questions were assessed by the DSM-IV checklist. Data were analyzed by the item response theory and the multiple indicators-multiple causes method procedures. RESULTS:Criterion symptoms of alcohol and marijuana dependences exhibited a high level of internal consistency. All individual symptoms showed good discrimination in distinguishing alcohol or marijuana users between high and low severity levels of the continuum. In both groups, "withdrawal" appeared to measure the most severe symptom of the dependence continuum. There was little evidence of measurement nonequivalence in assessing symptoms of dependence by gender, age, race/ethnicity, and educational level. CONCLUSIONS:These findings highlight the clinical utility of the DSM-IV checklist in assessing alcohol- and marijuana dependence syndromes among treatment-seeking substance users.Item Open Access Buprenorphine for prescription opioid addiction in a patient with depression and alcohol dependence.(The American journal of psychiatry, 2011-07) Fishman, Marc J; Wu, Li-Tzy; Woody, George EItem Open Access Co-occurring amphetamine use and associated medical and psychiatric comorbidity among opioid-dependent adults: results from the Clinical Trials Network.(Subst Abuse Rehabil, 2011-01-01) Pilowsky, Daniel J; Wu, Li-Tzy; Burchett, Bruce; Blazer, Dan G; Woody, George E; Ling, WalterBACKGROUND: In response to the rising rate of treatment admissions related to illicit use of amphetamines (eg, methamphetamine), we examined the prevalence of amphetamine use among treatment-seeking, opioid-dependent adults, explored whether amphetamine users were as likely as nonamphetamine users to enroll in opioid-dependence treatment trials, and determined whether amphetamine users manifested greater levels of medical and psychiatric comorbidity than nonusers. METHODS: The sample included 1257 opioid-dependent adults screened for participation in three-multisite studies of the National Drug Abuse Treatment Clinical Trials Network (CTN001-003), which studied the effectiveness of buprenorphine for opioid detoxification under varying treatment conditions. Patients were recruited from 23 addiction treatment programs across the US. Medical and psychiatric comorbidity were examined by past-month amphetamine use (current vs former) and route of administration. Five mutually exclusive groups were examined, ie, nonusers, current amphetamine injectors, current amphetamine noninjectors, former amphetamine injectors, and former amphetamine noninjectors. RESULTS: Of the sample (n = 1257), 22.3% had a history of regular amphetamine use. Of the 280 amphetamine users, 30.3% reported injection as their primary route. Amphetamine users were more likely than nonusers to be white and use more substances. Amphetamine users were as likely as non-users to enroll in treatment trials. Bivariate analyses indicated elevated rates of psychiatric problems (depression, anxiety, hallucinations, cognitive impairment, violence, suicidal thoughts/attempts) and medical illnesses (dermatological, hepatic, cardiovascular, respiratory, neurological, seizure, allergy conditions) among amphetamine users. After adjusting for demographic variables and lifetime use of other substances: current amphetamine users and former injectors showed an increased likelihood of having medical illnesses and hospitalizations; current injectors had elevated odds of suicidal thoughts or attempts; current noninjectors exhibited elevated odds of anxiety, cognitive impairment, and violent behaviors; and former noninjectors had increased odds of depression. CONCLUSION: Treatment-seeking, amphetamine-using, opioid-dependent adults manifest greater levels of medical and psychiatric morbidity than treatment-seeking, opioid-dependent adults who have not used amphetamines, indicating a greater need for intensive clinical management.Item Open Access Differences in onset and abuse/dependence episodes between prescription opioids and heroin: results from the National Epidemiologic Survey on Alcohol and Related Conditions.(Subst Abuse Rehabil, 2011-05) Wu, Li-Tzy; Woody, George E; Yang, Chongming; Mannelli, Paolo; Blazer, Dan GOBJECTIVES: To examine patterns of onset and abuse/dependence episodes of prescription opioid (PO) and heroin use disorders in a national sample of adults, and to explore differences by gender and substance abuse treatment status. METHODS: Analyses of data from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (N = 43,093). RESULTS: Of all respondents, 5% (n = 1815) reported a history of nonmedical PO use (NMPOU) and 0.3% (n = 150) a history of heroin use. Abuse was more prevalent than dependence among NMPOUs (PO abuse, 29%; dependence, 7%) and heroin users (heroin abuse, 63%; dependence, 28%). Heroin users reported a short mean interval from first use to onset of abuse (1.5 years) or dependence (2.0 years), and a lengthy mean duration for the longest episode of abuse (66 months) or dependence (59 months); the corresponding mean estimates for PO abuse and dependence among NMPOUs were 2.6 and 2.9 years, respectively, and 31 and 49 months, respectively. The mean number of years from first use to remission from the most recent episode was 6.9 years for PO abuse and 8.1 years for dependence; the mean number of years from first heroin use to remission from the most recent episode was 8.5 years for heroin abuse and 9.7 years for dependence. Most individuals with PO or heroin use disorders were remitted from the most recent episode. Treated individuals, whether their problem was heroin or POs, tended to have a longer mean duration of an episode than untreated individuals. CONCLUSION: Periodic remissions from opioid or heroin abuse or dependence episodes occur commonly but take a long time. Timely and effective use of treatment services are needed to mitigate the many adverse consequences from opioid/heroin abuse and dependence.Item Open Access Extended release naltrexone injection is performed in the majority of opioid dependent patients receiving outpatient induction: a very low dose naltrexone and buprenorphine open label trial.(Drug and alcohol dependence, 2014-05) Mannelli, Paolo; Wu, Li-Tzy; Peindl, Kathleen S; Swartz, Marvin S; Woody, George EThe approval of extended release injectable naltrexone (XR-NTX; Vivitrol(®)) has introduced a new option for treating opioid addiction, but studies are needed to identify its place within the spectrum of available therapies. The absence of physiological opioid dependence is a necessary and challenging first step for starting XR-NTX. Outpatient detoxification gives poor results and inpatient detoxification is either unavailable or too brief for the physiological effects of opioids to resolve. Here we present findings from an open label study that tested whether the transition from opioid addiction to XR-NTX can be safely and effectively performed in an outpatient setting using very low dose naltrexone and buprenorphine.Twenty treatment seeking opioid addicted individuals were given increasing doses of naltrexone starting at 0.25mg with decreasing doses of buprenorphine starting at 4 mg during a 7-day outpatient XR-NTX induction procedure. Withdrawal discomfort, craving, drug use, and adverse events were assessed daily until the XR-NTX injection, then weekly over the next month.Fourteen of the 20 participants received XR-NTX and 13 completed weekly assessments. Withdrawal, craving, and opioid or other drug use were significantly lower during induction and after XR-NTX administration compared with baseline, and no serious adverse events were recorded.Outpatient transition to XR-NTX combining upward titration of very low dose naltrexone with downward titration of low dose buprenorphine was safe, well tolerated, and completed by most participants. Further studies with larger numbers of subjects are needed to see if this approach is useful for naltrexone induction.Item Open Access Gender and racial/ethnic differences in addiction severity, HIV risk, and quality of life among adults in opioid detoxification: results from the National Drug Abuse Treatment Clinical Trials Network.(Subst Abuse Rehabil, 2010-12) Wu, Li-Tzy; Ling, Walter; Burchett, Bruce; Blazer, Dan G; Shostak, Jack; Woody, George EPURPOSE: Detoxification often serves as an initial contact for treatment and represents an opportunity for engaging patients in aftercare to prevent relapse. However, there is limited information concerning clinical profiles of individuals seeking detoxification, and the opportunity to engage patients in detoxification for aftercare often is missed. This study examined clinical profiles of a geographically diverse sample of opioid-dependent adults in detoxification to discern the treatment needs of a growing number of women and whites with opioid addiction and to inform interventions aimed at improving use of aftercare or rehabilitation. METHODS: The sample included 343 opioid-dependent patients enrolled in two national multi-site studies of the National Drug Abuse Treatment Clinical Trials Network (CTN001-002). Patients were recruited from 12 addiction treatment programs across the nation. Gender and racial/ethnic differences in addiction severity, human immunodeficiency virus (HIV) risk, and quality of life were examined. RESULTS: Women and whites were more likely than men and African Americans to have greater psychiatric and family/social relationship problems and report poorer health-related quality of life and functioning. Whites and Hispanics exhibited higher levels of total HIV risk scores and risky injection drug use scores than African Americans, and Hispanics showed a higher level of unprotected sexual behaviors than whites. African Americans were more likely than whites to use heroin and cocaine and to have more severe alcohol and employment problems. CONCLUSIONS: Women and whites show more psychopathology than men and African Americans. These results highlight the need to monitor an increased trend of opioid addiction among women and whites and to develop effective combined psychosocial and pharmacologic treatments to meet the diverse needs of the expanding opioid-abusing population. Elevated levels of HIV risk behaviors among Hispanics and whites also warrant more research to delineate mechanisms and to reduce their risky behaviors.Item Open Access How do prescription opioid users differ from users of heroin or other drugs in psychopathology: results from the National Epidemiologic Survey on Alcohol and Related Conditions.(Journal of addiction medicine, 2011-03) Wu, Li-Tzy; Woody, George E; Yang, Chongming; Blazer, Dan GTo study substance use and psychiatric disorders among prescription opioid users, heroin users, and non-opioid drug users in a national sample of adults.Analyses of data from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (N=43,093).Four groups were identified among 9140 illicit or non-prescribed drug users: heroin-other opioid users (1.0%; used heroin and other opioids), other opioid-only users (19.8%; used other opioids but never heroin), heroin-only users (0.5%; used heroin but never other opioids), and non-opioid drug users (78.7%; used drugs but never heroin or other opioids). After adjusting for variations in socioeconomic characteristics, history of substance abuse treatment, and familial substance abuse, heroin-other opioid users had greater odds of several substance use disorders (cocaine, hallucinogen, sedative, amphetamine, and tranquilizer) as compared with the other groups; heroin-only users had reduced odds of sedative and tranquilizer use disorders as compared with other opioid-only users. Non-opioid drug users had reduced odds of all substance use disorders and other mental disorders (mood, anxiety, pathological gambling, and personality) as compared with other opioid-only users. Past-year other opioid-only users also reported slightly lower scores on quality of life than past-year non-opioid drug users.All opioid use groups had higher rates of substance use disorders than non-opioid drug users, and these rates were particularly elevated among heroin-other opioid users. Findings suggest the need to distinguish between these four groups in research and treatment as they may have different natural histories and treatment needs.Item Open Access Racial/ethnic variations in substance-related disorders among adolescents in the United States.(Archives of general psychiatry, 2011-11) Wu, Li-Tzy; Woody, George E; Yang, Chongming; Pan, Jeng-Jong; Blazer, Dan GWhile young racial/ethnic groups are the fastest growing population in the United States, data about substance-related disorders among adolescents of various racial/ethnic backgrounds are lacking.To examine the magnitude of past-year DSM-IV substance-related disorders (alcohol, marijuana, cocaine, inhalants, hallucinogens, heroin, analgesic opioids, stimulants, sedatives, and tranquilizers) among adolescents of white, Hispanic, African American, Native American, Asian or Pacific Islander, and multiple race/ethnicity.The 2005 to 2008 National Survey on Drug Use and Health.Academic research.Noninstitutionalized household adolescents aged 12 to 17 years.Substance-related disorders were assessed by standardized survey questions administered using the audio computer-assisted self-interviewing method.Of 72 561 adolescents aged 12 to 17 years, 37.0% used alcohol or drugs in the past year; 7.9% met criteria for a substance-related disorder, with Native Americans having the highest prevalence of use (47.5%) and disorder (15.0%). Analgesic opioids were the second most commonly used illegal drugs, following marijuana, in all racial/ethnic groups; analgesic opioid use was comparatively prevalent among adolescents of Native American (9.7%) and multiple race/ethnicity (8.8%). Among 27 705 past-year alcohol or drug users, Native Americans (31.5%), adolescents of multiple race/ethnicity (25.2%), adolescents of white race/ethnicity (22.9%), and Hispanics (21.0%) had the highest rates of substance-related disorders. Adolescents used marijuana more frequently than alcohol or other drugs, and 25.9% of marijuana users met criteria for marijuana abuse or dependence. After controlling for adolescents' age, socioeconomic variables, population density of residence, self-rated health, and survey year, adjusted analyses of adolescent substance users indicated elevated odds of substance-related disorders among Native Americans, adolescents of multiple race/ethnicity, adolescents of white race/ethnicity, and Hispanics compared with African Americans; African Americans did not differ from Asians or Pacific Islanders.Substance use is widespread among adolescents of Native American, white, Hispanic, and multiple race/ethnicity. These groups also are disproportionately affected by substance-related disorders.Item Open Access Recent national trends in Salvia divinorum use and substance-use disorders among recent and former Salvia divinorum users compared with nonusers.(Subst Abuse Rehabil, 2011-04) Wu, Li-Tzy; Woody, George E; Yang, Chongming; Li, Jih-Heng; Blazer, Dan GCONTEXT: Media and scientific reports have indicated an increase in recreational use of Salvia divinorum. Epidemiological data are lacking on the trends, prevalence, and correlates of S. divinorum use in large representative samples, as well as the extent of substance use and mental health problems among S. divinorum users. OBJECTIVE: To examine the national trend in prevalence of S. divinorum use and to identify sociodemographic, behavioral, mental health, and substance-use profiles of recent (past-year) and former users of S. divinorum. DESIGN: Analyses of public-use data files from the 2006-2008 United States National Surveys on Drug Use and Health (N = 166,453). SETTING: Noninstitutionalized individuals aged 12 years or older were interviewed in their places of residence. MAIN MEASURES: Substance use, S. divinorum, self-reported substance use disorders, criminality, depression, and mental health treatment were assessed by standardized survey questions administered by the audio computer-assisted self-interviewing method. RESULTS: Among survey respondents, lifetime prevalence of S. divinorum use had increased from 0.7% in 2006 to 1.3% in 2008 (an 83% increase). S. divinorum use was associated with ages 18-25 years, male gender, white or multiple race, residence of large metropolitan areas, arrests for criminal activities, and depression. S. divinorum use was particularly common among recent drug users, including users of lysergic acid diethylamide (53.7%), ecstasy (30.1%), heroin (24.2%), phencyclidine (22.4%), and cocaine (17.5%). Adjusted multinomial logistic analyses indicated polydrug use as the strongest determinant for recent and former S. divinorum use. An estimated 43.0% of past-year S. divinorum users and 28.9% of former S. divinorum users had an illicit or nonmedical drug-use disorder compared with 2.5% of nonusers. Adjusted logistic regression analyses showed that recent and former S. divinorum users had greater odds of having past-year depression and a substance-use disorder (alcohol or drugs) than past-year alcohol or drug users who did not use S. divinorum. CONCLUSION: S. divinorum use is prevalent among recent or active drug users who have used other hallucinogens or stimulants. The high prevalence of substance use disorders among recent S. divinorum users emphasizes the need to study health risks of drug interactions.Item Open Access Substance use disorders and comorbid Axis I and II psychiatric disorders among young psychiatric patients: findings from a large electronic health records database.(Journal of psychiatric research, 2011-11) Wu, Li-Tzy; Gersing, Ken; Burchett, Bruce; Woody, George E; Blazer, Dan GThis study examined the prevalence of substance use disorders (SUDs) among psychiatric patients aged 2-17 years in an electronic health records database (N=11,457) and determined patterns of comorbid diagnoses among patients with a SUD to inform emerging comparative effectiveness research (CER) efforts. DSM-IV diagnoses of all inpatients and outpatients at a large university-based hospital and its associated psychiatric clinics were systematically captured between 2000 and 2010: SUD, anxiety (AD), mood (MD), conduct (CD), attention deficit/hyperactivity (ADHD), personality (PD), adjustment, eating, impulse-control, psychotic, learning, mental retardation, and relational disorders. The prevalence of SUD in the 2-12-year age group (n=6210) was 1.6% and increased to 25% in the 13-17-year age group (n=5247). Cannabis diagnosis was the most prevalent SUD, accounting for more than 80% of all SUD cases. Among patients with a SUD (n=1423), children aged 2-12 years (95%) and females (75-100%) showed high rates of comorbidities; blacks were more likely than whites to be diagnosed with CD, impulse-control, and psychotic diagnoses, while whites had elevated odds of having AD, ADHD, MD, PD, relational, and eating diagnoses. Patients with a SUD used more inpatient treatment than patients without a SUD (43% vs. 21%); children, females, and blacks had elevated odds of inpatient psychiatric treatment. Collectively, results add clinical evidence on treatment needs and diagnostic patterns for understudied diagnoses.Item Open Access Subtypes of nonmedical opioid users: results from the national epidemiologic survey on alcohol and related conditions.(Drug and alcohol dependence, 2010-11) Wu, Li-Tzy; Woody, George E; Yang, Chongming; Blazer, Dan GTo identify subtypes of nonmedical opioid users, gender variations in psychiatric disorders, and quality of life in a representative sample of adults.Analyses of data from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (N=43,093). Latent class analysis (LCA) and multinomial logistic regression procedures examined subtypes of nonmedical opioid users.Approximately 5% (n=1815) of adults used nonmedical opioids. LCA identified four subtypes: opioid-marijuana users (33%), opioid-other prescription drug users (9%), opioid-marijuana-hallucinogen users (28%), and opioid-polydrug users (30%). Subtypes were distinguished by race/ethnicity, gender, familial substance abuse, personal history of substance abuse treatment, and patterns of psychiatric disorders. Whites and men had increased odds of being in the opioid-polydrug and opioid-marijuana-hallucinogen subtypes. The opioid-other prescription drug use subtype had disproportionately affected women who were characterized by high rates of mood/anxiety disorders and low quality of life. Across all subtypes, women and men had similarly problematic substance use disorders; however, women had more major depression and disability in the mental health domain.The generally high prevalence of psychiatric disorders among nonmedical opioid users, particularly women, underscores the need for comprehensive assessment and coordinated delivery of services to match needs with treatment, as well as continued monitoring of trends in opioid use and related problems.Item Open Access Treatment use and barriers among adolescents with prescription opioid use disorders.(Addictive behaviors, 2011-12) Wu, Li-Tzy; Blazer, Dan G; Li, Ting-Kai; Woody, George EThis study examined national trends, patterns, correlates, and barriers to substance abuse treatment use by adolescents aged 12-17 years who met at least one of the past-year criteria for prescription opioid abuse or dependence (N=1788).Data were from the 2005-2008 National Surveys of Drug Use and Health (NSDUH). Past-year substance use disorders, major depression, and treatment use were assessed by audio computer-assisted self-interviewing.About 17% of adolescents with opioid dependence (n=434) and 16% of those with opioid abuse (n=355) used any substance abuse treatment in the past year compared with 9% of subthreshold users, i.e., adolescents who reported 1-2 prescription opioid dependence criteria but no abuse criteria (n=999). Only 4.2% of adolescents with opioid dependence, 0.5% of those with abuse, and 0.6% of subthreshold users reported a perceived need for treatment of nonmedical opioid use. Self-help groups and outpatient rehabilitation were the most commonly used sources of treatment. Few black adolescents used treatment (medical settings, 3.3%; self-help groups, 1.7%) or reported a need for treatment (1.8%). Talking to parents/guardians about dangers of substance use increased the odds of treatment use. Barriers to treatment use included "wasn't ready to stop substance use," "didn't want others to find out," and "could handle the problem without treatment."Adolescents with prescription opioid use disorders markedly underutilize treatment. Non-financial barriers are pervasive, including stigma and a lack of perceived treatment need.Item Open Access 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.(Drug and alcohol dependence, 2011-11) Wu, Li-Tzy; Ling, Walter; Burchett, Bruce; Blazer, Dan G; Yang, Chongming; Pan, Jeng-Jong; Reeve, Bryce B; Woody, George EBACKGROUND: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.Item Open Access Using a latent variable approach to inform gender and racial/ethnic differences in cocaine dependence: a National Drug Abuse Treatment Clinical Trials Network study.(Journal of substance abuse treatment, 2010-06) Wu, Li-Tzy; Pan, Jeng-Jong; Blazer, Dan G; Tai, Betty; Stitzer, Maxine L; Woody, George EThis study applies a latent variable approach to examine gender and racial/ethnic differences in cocaine dependence, to determine the presence of differential item functioning (DIF) or item-response bias to diagnostic questions of cocaine dependence, and to explore the effects of DIF on the predictor analysis of cocaine dependence. The analysis sample included 682 cocaine users enrolled in two national multisite studies of the National Drug Abuse Treatment Clinical Trials Network (CTN). Participants were recruited from 14 community-based substance abuse treatment programs associated with the CTN, including 6 methadone and 8 outpatient nonmethadone programs. Factor and multiple indicators-multiple causes (MIMIC) procedures evaluated the latent continuum of cocaine dependence and its correlates. MIMIC analysis showed that men exhibited lower odds of cocaine dependence than women (regression coefficient, beta = -0.34), controlling for the effects of DIF, years of cocaine use, addiction treatment history, comorbid drug dependence diagnoses, and treatment setting. There were no racial/ethnic differences in cocaine dependence; however, DIF by race/ethnicity was noted. Within the context of multiple community-based addiction treatment settings, women were more likely than men to exhibit cocaine dependence. Addiction treatment research needs to further evaluate gender-related differences in drug dependence in treatment entry and to investigate how these differences may affect study participation, retention, and treatment response to better serve this population.