Predicting Cocaine Group Treatment Outcome in Cocaine-Abusing
Methadone Patients
Golfo K. Tzilos, Gary L. Rhodes, David M. Ledgerwood, and Mark K. Greenwald
Wayne State University
The authors examined predictors of cocaine group treatment outcome in methadone main-
tenance treatment (MMT) patients, including cocaine urinalysis at intake and demographic
variables. Clinic policy is that patients identified as using cocaine must attend a weekly
cocaine-focused, cognitive– behavioral therapy (CBT) group. Cocaine treatment is based on
a behavioral (escape) contingency model whereby completers must attend group-counseling
sessions and produce cocaine-negative urinalysis results. Among the 113 patients enrolled in
the cocaine group, 43 (38%) were treatment completers (who attended 6 consecutive weeks
of group and produced 6 consecutive weeks of cocaine-free urine tests) and 70 (62%) were
treatment noncompleters. Treatment completion (i.e., cocaine abstinence) was significantly
associated with baseline cocaine-free urinalysis and higher methadone dose.
Keywords: methadone maintenance, cocaine, treatment, contingency management, urinalysis
Up to 75% of opioid-dependent patients also use cocaine
while in methadone maintenance treatment (MMT; Grella,
Anglin, & Wugalter, 1995). MMT was designed to control
only opioid dependence. Concomitant use of cocaine un-
dermines therapeutic efforts in MMT (Barthwell & Gast-
friend, 1992; Black, Dolan, Penk, Robinowitz, & Deford,
1987); for example, increasing the number of MMT patients
who fail to comply with clinic rules, making the treatment
and rehabilitation of these patients a particular challenge.
Results from an ever-increasing number of clinical trials
indicate that cocaine use at treatment baseline predicts
worse outcome; for example, attrition and failure to attain
initial abstinence (Alterman et al., 1997; Carroll et al., 1994;
DeMaria, Sterline, & Weinstein, 2000; Downey, Helmus, &
Schuster, 2000; Ehrman, Robbins, & Cornish, 2001;
Kosten, Sofuoglu, Poling, Gonsai, & Oliveto, 2005; Marsch
et al., 2005; Peirce et al., 2009; Preston et al., 1998; Sofuo-
glu, Gonzalez, Poling, & Kosten, 2003; Stitzer et al., 2007),
suggesting that this may be an important predictor of treat-
ment response.
Substance abuse treatment programs have routinely in-
cluded forms of targeted behavioral reinforcement, such as
take-home methadone privileges for patients who maintain
long periods of abstinence or exhibit reductions in drug use
(Petry, 2000). One such strategy is the set of interventions
called contingency management (CM), in which a clinically
desired behavior (i.e., drug use reduction or abstinence) is
monitored using urinalysis and reinforced (Stitzer & Petry,
2006). For example, patients can receive vouchers or
take-home methadone dose privileges as the reinforcer
when they are treatment compliant. Numerous studies
have demonstrated that CM is an efficacious treatment
strategy when applied systematically to modify undesired
behaviors in the treatment of alcohol, marijuana, benzodi-
azepine, cocaine, opioid, and polydrug use (Bickel, Amass,
Higgins, Badger, & Esch, 1997; Budney, Higgins, Rado-
novich, & Novy, 2000; Dutra et al., 2008; Higgins et al.,
1991, Higgins et al., 1993, 1994, 2000; Petry, 2000; Petry &
Martin, 2002; Piotrowski et al., 1999; Silverman et al.,
2004; Stitzer, Iguchi, & Felch, 1992, Stitzer, Petry, & Sil-
verman, 1999). Higgins et al. (1991, Higgins et al., 1993,
Higgins et al., 1994, Higgins et al., 1995, Higgins et al.,
2000) developed and applied a voucher-based reinforce-
ment approach for treatment of cocaine dependence with a
series of studies that demonstrated efficacy (i.e., increased
cocaine abstinence) during treatment and up to 1 year later.
Silverman et al. (1996, 1998) extended this reinforcement
approach to cocaine-abusing methadone patients, with their
studies yielding similar results of cocaine abstinence, as
well as increased rates of abstinence from opiates. More
recently, adding CM to a standard substance abuse group
therapy was found to be effective in improving therapy
attendance (Ledgerwood, Alessi, Hanson, Godley, & Petry,
2008; Petry, Martin, & Finocche, 2001). Griffith, Rowan-
Szal, Roark, and Simpson (2000) conducted a meta-analysis
demonstrating the effectiveness of CM programs for meth-
adone patients and concluded that a CM treatment approach
reduced drug use in this population.
Escape-contingency management is a negative reinforce-
ment technique that has been applied in the treatment of
substance abuse. For example, Brooner and colleagues
(2004) evaluated a motivated stepped-care (MSC) interven-
tion in 127 opioid-dependent patients using methadone.
Golfo K. Tzilos, Department of Psychology, Wayne State Univer-
sity; Gary L. Rhodes, David M. Ledgerwood, and Mark K. Green-
wald, Substance Abuse Research Division, Department of Psychiatry
and Behavioral Neurosciences, Wayne State University School of
Medicine.
Correspondence concerning this article should be addressed to
Golfo K. Tzilos, Substance Abuse Research Division, Wayne State
University, 2761 E. Jefferson Avenue, Detroit, MI 48207. E-mail:
gtzilos@wayne.edu
Experimental and Clinical Psychopharmacology © 2009 American Psychological Association
2009, Vol. 17, No. 5, 320 –325 1064-1297/09/$12.00 DOI: 10.1037/a0016835
320
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