INTRODUCTION
Use of cocaine is the major cause of high-risk behaviors for HIV (human immunodeficiency virus) infection and/or transmission has been well documented. This relationship obtains for heroin addicts who also use cocaine and has complicated the treatment needs and outcomes of addicts who enter methadone maintenance treatment. The proliferation of cocaine use, including crack, among heroin addicts in methadone treatment is particularly troublesome because of its association with criminal behavior and with HIV risk behaviors.
Although methadone maintenance treatment is an opiate substitution therapy, specific for heroin addiction, several studies have evaluated the effects of methadone maintenance treatment on cocaine use. Previous research has demonstrated that while the majority of clients ceases or reduces cocaine use after entering methadone maintenance treatment, other clients begin or even increase cocaine use. Cocaine use among heroin addicts in methadone treatment is strongly associated with continued heroin use. Increased use of cocaine after entering treatment has been associated with problems across a wide psychosocial spectrum, including employment, familial, psychological, and legal, and especially with symptoms of depression. Methadone clients who increase their use of cocaine may do so because it provides them with a substitute high for heroin. In a study of a cohort of injection drug users admitted into methadone treatment, persistent crack use over a period of approximately 3 years was associated with the number of noninjected drugs used at intake and with severe depression, including suicidal ideation or attempts.
This paper examines the patterns of cocaine and crack use, and predictors of those patterns, among heroin addicts before and after admission to the UCLA Enhanced Methadone Maintenance (EMM) Project. The EMM Project was a research demonstration project funded by the National Institute on Drug Abuse from 1989 to 1994. The primary goal of the project was to recruit and retain in methadone treatment high-risk addicts in order to reduce their level of risk for HIV infection and/or transmission, consistent with a harm reduction approach. The enhanced methadone maintenance treatment protocol paid particular attention to cocaine use because of its pervasiveness among the sample, its interference with achieving positive treatment outcomes, and its association with a number of behaviors that increase risk for HIV transmission.
Our previous investigation of cocaine use in this sample focused on the characteristics of cocaine and crack users at admission into the EMM Project. We demonstrated that heroin addicts using cocaine within the 12 months prior to treatment entry, compared with noncocaine-using heroin addicts, had a higher-risk profile for HIV infection or transmission from unsafe needle use and sexual behavior; were more criminally involved; were more likely to be African American; used alcohol more frequently; and scored higher on measures of suicidality, hopelessness, and depression. Additionally, heroin addicts who used crack demonstrated an even higher risk profile of behaviors when compared with noncrack cocaine-using heroin addicts. The analysis contained in the present paper builds upon this distinction between the different types of cocaine use by examining the changes in their use after treatment admission and by determining the characteristics of clients and treatment that are predictive of different patterns of cocaine use. The paper also reports on a validity assessment of self-reported cocaine use by comparing self-report data with results of urinalysis tests.
METHOD
Sample
A total of 500 injecting heroin addicts at high risk for HIV infection or transmission were recruited into the EMM Project from 1990 to 1993. Four target groups for admission were designated on the basis of local seroprevalence studies of injection drug users (IDUs). The target groups were HIV-positive individuals, gay or bisexual males, sex workers (prostitutes), and sex partners of individuals in any of the above three categories. Subjects were recruited through outreach to local service providers (e.g., AIDS service organizations, social welfare programs, health clinics), flier distribution, and client word-of-mouth. Methadone treatment was provided at a clinic established for the purposes of this study, located in central Los Angeles, an area dense with sex workers, "crack motels," and drug dealers. See Grella and Anglin's description of the implementation of the demonstration project and research study.
Prospective subjects were evaluated at the methadone clinic by a member of the research staff for their eligibility for methadone maintenance treatment, according to federal and State of California regulations,(*) and for the study, which required membership in at least one of the four high-risk target groups.([dagger]) Eligible subjects were admitted into the project after providing informed consent to participate in the research study, which included random assignment to one of two treatment conditions: either standard or enhanced methadone maintenance. Individuals in the enhanced treatment group received an array of additional services: transportation assistance in the first 90 days after admission; case management services, including a reduced ratio of clients to case managers; access to special groups, such as an HIV education group, a group for cocaine users, and a women's group; on-site psychiatric assessment and medication; and contingency-based reinforcers, such as food coupons, movie passes, and restaurant coupons, to improve quality of life and promote drug-free activities. Hasson et al. discuss the case management protocol and barriers to its implementation. All research subjects received free methadone maintenance treatment through the duration of the study (which ended November 30, 1994) and were asked to contribute in an intake interview at treatment entry and a follow-up interview, occurring approximately after 18-24 months admission, which assessed behavior subsequent to treatment entry.