Addictive Behaviors, Vol. 20, No. 1, pp. 117-125, 19% Copyright 0 1995 Elsevier Science Ltd Printed in the USA. All rights reserved 0306-4603/95 $9.SO t .OO zyxwvu PARTICIPATION IN A PARENT TRAINING PROGRAM FOR METHADONE CLIENTS RANDY R. GAINEY, RICHARD F. CATALANO, KEVIN P. HAGGERTY, and MARILYN J. HOPPE Social Development Research Group, School of Social Work, University of Washington. Seattle Abstract - Programs for drug abusers are plagued by high rates of dropout. Because of the strong relationship between longer treatment and positive outcome, researchers have begun to study individual and program-specific factors that influence premature termination of treatment. For the most part, these studies have focused on dichotomous measures of dropout or number of sessions attended. In this article, we extend this line of research in two ways. First, we develop and measure a number of indicators of treatment participation based on therapist ratings. Second, we develop a model of treatment participation that employs both individual and program-specific factors. The data show that tremendous varia- tion in participation occurred even among those who attended a majority of sessions, which highlights the importance of obtaining more elaborate measures of treatment participation. The model predicting treatment participation suggests that initiation of heroin use later in life, continued use of marijuana, and behavioral indicators of motivation are the strongest predictors of program participation. Research and practical implications of the findings are discussed. Treatment programs for drug abusers are plagued by high dropout rates (Catalan0 et al., 1988; DeLeon, Wexler, & Jainchill, 1982). Consistent empirical evidence indi- cates that continued use or relapse is associated with exposure, usually measured by number of sessions attended (Allison & Hubbard, 1985; DeLeon, Wexler, & Jain- chill, 1982; Hubbard et al., 1989; McLellan, Luborsky, & Woody, 1983; Roffman et al., 1993; Simpson & Sells, 1982). Measures of treatment participation and compli- ance have not been adequately addressed. Clients may attend a relatively large number of sessions but not pay close attention, actively participate, or comply with the structure of the program. We argue that although program dropout and attend- ance are important, the addition of client participation measures (e.g., involvement in program activities) will provide a more reliable predictor of treatment outcome, especially among frequent attenders. Dropout also reduces the statistical power to detect experimental effects, hamper- ing the assessment of treatment efficacy (Boruch & Gomez, 1977: Cook & Poole, 1982; Wells et al., 1994). Treatment participation data can increase statistical power in experimental designs, although this introduces its own limitations and biases. Cook and Poole (1982, p. 426) note that “even in well designed studies, persons can self-select into different levels of service receipt.” Because self-determined levels of treatment exposure are likely to be associated with individual characteristics such as interest or motivation, artificial biases in favor of the experimental condition may This research was supported by grant 5 R01 DA05824-02 from the National Institute on Drug Abuse. An earlier draft of this article was presented at the Annual Meetings of the American Society of Criminol- ogy in New Orleans, Louisiana, November. 1992. Requests for reprints should be sent to Randy Gainey, Social Development Research Group. 146 North Canal, Suite 211, Seattle, WA 98103. 117