Randomized trial of continuing care enhancements for cocaine-dependent patients following initial engagement.

One of the pressing needs in the treatment of substance use disorders is the identification of adjunctive services or interventions that can be added to “treatment as usual” to improve outcomes. At this point, there is evidence that the provision of services to address psychiatric, family, employment, and housing problems can bring about improvements in these areas, and in some cases, in substance use outcomes (Friedmann, Hendrickson, Gerstein, & Zhang, 2004; McLellan et al., 1997, 1998; O'Farrell, Choquette, & Cutter, 1998). Continuing care, which serves to extend the duration of treatment, has also been shown to improve substance use outcomes (McKay, 2005). However, it can be difficult to deliver adjunctive interventions to patients in standard outpatient treatment due to the high drop out rates in these programs. For example, recent data from a national survey of addictions treatment programs indicated that the median length of stay in intensive outpatient programs was 46 days, with only 36% of admissions completing treatment (SAMHSA, 2008). One intervention that has shown considerable promise as a means to both increase retention and improve substance use outcomes is contingency management (CM), which provides incentives linked to performance. CM interventions, most notably in the form of voucher-based reinforcement therapy (VBRT) for abstinence, have demonstrated efficacy in the treatment of substance use disorders, as documented in several recent meta-analyses (Dutra, Stathopoulou, Basden, Leyro, Powers, & Otto, 2008; Lussier, Heil, Mongeon, Badger, & Higgines, 2006, Prendergast, Podus, Finney, Greenwell, & Roll, 2006). Notably, CM interventions have also proved effective in community settings (Petry, Alessi, Marx, Austin, & Tardif, 2005; Petry, Alessi, & Hanson, 2007). The majority of trials utilizing CM for drug abstinence have focused on initiating abstinence early in treatment. What has been much less frequently addressed is whether CM works as an adjunctive relapse prevention intervention in individuals who have achieved initial engagement in treatment and already sharply reduced or stopped using drugs. Another intervention that, at least theoretically, should promote better outcomes in initially stabilized patients with substance use disorders is relapse prevention, or RP (Marlatt & Gordon, 1985). Most RP interventions make use of techniques from cognitive-behavioral and social skills therapies to increase awareness of situations in which the individual has been particularly likely to use drugs (i.e., “high risk situations”) and improve coping responses for these situations through rehearsal and homework assignments (Annis & Davis, 1989; Carroll, 1998; Marlatt & Gordon, 1985). Improvements in these areas are thought to increase self-efficacy, which in term promotes further improvements in coping abilities. Although CBT-based interventions are widely seen as evidence-based (Carroll, 1996), recent research has suggested they are not more effective than other bona fide treatments for substance use disorders, whether delivered as a primary treatment or as a form of continuing care (Dutra et al., 2008; Irvin, Bowers, Dunn, & Wang, 1999; Longabaugh & Morgenstern, 1999; McKay et al., 1999; McKay, Lynch, Shepard, & Pettinati, 2005; Morgenstern & McKay, 2007; Rawson et al., 2006). Therefore, it is not clear that supplementing standard addiction treatment with RP for patients who have achieved initial engagement will in fact lead to better outcomes. There is also mixed evidence regarding possible additive effects for interventions that combine RP/CBT and CM over RP/CBT or CM alone. Epstein, Hawkins, Covi, Umbricht, and Preston (2003) reported that CM alone was more effective in decreasing cocaine use in methadone maintenance patients than CM+CBT during treatment, but additive effects favoring the CM+CBT condition over CM alone emerged at 12 months. Shoptaw et al. (2005) found that methamphetamine dependent participants had better drug use outcomes in CM+CBT than in CBT alone, but the combination condition was not more effective than CM alone. Finally, in studies with methadone maintenance and methamphetamine dependent patients, Rawson and colleagues found that while shorter term outcomes favored CM over CBT or control conditions, longer term outcomes in CBT conditions were not different from those in CM conditions. Moreover, there were no additive effects for CM+CBT over CM or CBT (Rawson et al., 2002; Rawson et al., 2006). It should be noted that all of these studies were done as abstinence-initiation projects, rather than as continuing care or relapse prevention projects. Another important consideration in the selection of adjunctive interventions to reduce relapse in stabilized patients is whether the effects of the intervention persist into the post-treatment period. There is some evidence that RP/CBT interventions can exhibit sleeper effects, where the positive effects of the intervention in relation to comparison conditions does not become apparent until after the interventions are over (Carroll et al., 1994; McKay et al., 1999; Rawson et al., 2002; Rawson et al., 2006), although this is not the case in all studies. Until recently, most studies of CM did not have post-treatment follow-ups. However, a number of newer studies have included post-treatment follow-ups, usually out to 12 months. The results have been mixed, with some studies showing evidence of sustained voucher effects (Alessi, Hanson, Wieners, & Petry, 2007; Epstein et al., 2003; Higgins, Wong, Badger, Ogden, & Dantona, 2000; Higgins et al., 2003; Higgins et al., 2006), and other studies showing no sustained effects (Milby et al., 2003; Petry et al., 2005; Petry et al., 2006; Rawson et al., 2002; Rawson et al., 2006; Shoptaw et al., 2005). This paper presents results from a program of research on the effectiveness of enhancements to improve continuing care in outpatient specialty care for drug and alcohol dependence. Participants were recruited from cocaine-dependent patients attending a publicly funded intensive outpatient program (IOP) in Philadelphia, who had successfully engaged in IOP for at least two weeks and met other study inclusion criteria. They also reported that they had been abstinent for an average of 44 consecutive days at entrance into the study, although abstinence was not a requirement for participation. The study featured a 2 × 2 design, which crossed contingency management (CM; yes/no) with relapse prevention (RP; yes/no). The CM protocol used in the study was modeled after the protocol developed by Silverman et al. (1996), which in turn was adapted from work by Higgins and colleagues (1993). Participants earned vouchers for cocaine-free urines on an escalating schedule over a 12 week period, with a total maximal value of $1,150 if all urines were cocaine-free. The vouchers could be redeemed for goods and services consistent with recovery. The cognitive-behavioral RP protocol (Annis & Davis, 1989) was delivered in up to 20 weekly individual sessions. Participants in the condition that provided both CM and RP were required to be attending their RP sessions for the first 12 weeks in order to be eligible to participate in the CM procedures during that time. The primary goal of the study was to determine whether providing CM, RP, or the combination of CM and RP to participants who had achieved initial engagement in intensive outpatient treatment would produce better cocaine use outcomes than treatment as usual (TAU) over an 18 month follow-up period. We predicted that significant main effects for CM and RP would be obtained, and the best outcomes would be found in the CM+RP condition. These predictions were tested through an examination of main and interaction effects in the 2 × 2 design and post hoc contrast analyses that compared the four treatment conditions.