An extensive literature assessing motivation to change among people with alcohol problems is not matched by a similar literature in patients with drug dependence (DiClemente et al., 2004). Patients who are drug dependent differ in clinically significant ways from patients who are alcohol dependent (Brower et al., 1994). For example, patients who use drugs are more often mandated to treatment due to illegal behaviors and may differ in regard to the severity of their substance abuse problems or their level of psychosocial impairment. As a result, it has been suggested that drug abuse patients have a poorer prognosis in treatment than alcohol abuse patients (Weisner, 1992). A better understanding of how to best measure motivation to change and how motivation relates to successful behavior change among both drug and alcohol dependent patients would broaden our understanding of the role of motivation in the treatment of addictions.

The use of valid measure of motivation to change is critical to understanding the potential impact of this construct on treatment outcomes. Although several measures have been developed (i.e., SOCRATES, Change Ladder, and Stages of Change Algorithm), the University of Rhode Island Change Assessment (URICA) is one of the most commonly used measures of motivation to change (Carey et al., 1999; DiClemente et al., 1999; DiClemente and Hughes, 1990). The URICA is based on the stages of change model and has four subscales: precontemplation, contemplation, action and maintenance. The psychometrics of the URICA have been assessed in a wide variety of individuals with substance-related disorders including alcohol, drug, and polysubtance dependence with mixed results (Abellanas and McLellan, 1993; Belding et al., 1997; Belding et al., 1995; Carbonari and DiClemente, 2000; DiClemente and Hughes, 1990; DiClemente et al., 1999; Edens and Willoughby, 1999; Edens and Willoughby, 2000; el-Bassel et al., 1998; Willoughby and Edens, 1996). One of the more common approaches to evaluating the URICA is to define groups of patients across the spectrum of motivation using cluster analysis. Using cluster analysis, the URICA has been found to reflect anywhere between two and eight subgroups of patients (Blanchard, 2003; DiClemente and Hughes, 1990; Di-Clemente et al., 1991; el-Bassel, 1998; McConnaughy et al., 1983; McConnaughy et al., 1989; Pantalon and Swanson, 2003; Prochaska and DiClemente, 1983; Siegal et al., 2001). Construct validity is more commonly evaluated using factor analysis. However, few studies have evaluated the URICA’s construct validity using factor analysis and these typically rely on principal components analysis, a more exploratory approach to examining factor structure. Four studies using principal components analysis, including two among substance abuse populations, supported a four-factor solution that accounted for 39% to 58% of the variance (Carney and Kivlahan, 1995; DiClemente and Hughes, 1990; McConnaughy et al., 1989; McConnaughy et al., 1983). Another study identified a five-factor solution among incarcerated drug users (el-Bassel et al, 1998). Using confirmatory factor analyses with polysubstance abusers, one study failed to confirm the four-factor structure (Belding et al., 1996) while another supported the four factor structure (Pantalon, et al., 2002). There are currently no studies comparing the a priori four-factor structure of the URICA using confirmatory factor analysis across substances of abuse which may, in part, account for these mixed findings.

Results regarding the predictive validity of the URICA have been as equally mixed as those examining its construct validity (Belding et al., 1997; Blanchard et al., 2003; Carey et al 2001; DiClemente, 1999; Edens and Willoughby, 1999; Pantalon et al., 2002; Pantalon and Swanson, 2003; Siegal et al., 2001; Willoughby and Edens, 1996). Among polydrug dependent patients in methadone maintenance, Belding et al. (1997) found that the contemplation score was modestly associated (r=-.29, p<.05) with drug free urine one month after admission but observed a non-significant association between the action stage and treatment retention (r=-.22). Edens and Willoughby (1999) found inpatients with polysubstance abuse in the contemplation and action cluster were significantly more likely to complete treatment than those in the precontemplation cluster (69% vs. 53%, p=.03). However, Pantalon and Swanson (2003) found that dually diagnosed, polysubstance dependent inpatients with low readiness to change attended a greater proportion of therapy session while hospitalized (54% vs. 39%, p<.05) and clinic appointments one month post-discharge (77% vs. 53%, p<.05) than those with high readiness to change. In another study of predominately alcohol and cocaine dependent patient in the outpatient and community setting, readiness to change failed to predict treatment adherence, percent days abstinent or negative consequences at three or six month follow up (Blanchard et al, 2003).

While the predictive validity among patients with drug abuse and dependence has generally been considered more difficult to establish than patients with alcohol problems, there are equally mixed results for the predictive validity among patients with alcohol dependence (Belding et al., 1997; Blanchard et al., 2003; Carey et al 2001; DiClemente, 1999; Pantalon et al., 2002; Pantalon and Swanson, 2003; Siegal et al., 2001). For example, in one study Edens and Willoughby (1999) found that patients in the contemplation and action cluster were more likely to complete treatment than those in the precontemplation cluster (75% vs. 54%, p=.004) while another study found no such association (Willoughby and Edens, 1996). Given the mixed and relatively modest results across substances of abuse, a comparison of the predictive validity of motivation to change in a representative sample of outpatients treated by an evidence-based treatment, specifically designed to increase readiness to change (i.e., motivational interviewing or motivational enhancement therapy), may clarify existing research.

In a majority of studies that use the URICA with patients seeking treatment, the four subscale scores are significantly skewed such that the contemplation, action, and maintenance scores are typically high and precontemplation scores are usually low. As a result, a sophisticated method of clustering individuals based on their patterns of scores across the four subscales is sometimes employed to create stage-based subgroups (Carney and Kivilahan, 1995; Miller, 1985). However, clustering patients into stage-based subgroups is complicated and impractical in a clinical setting. Cluster analysis is often sample-specific, making it difficult to interpret an individual’s score prior to data analysis for a given sample (Carey et al., 1999). To address these concerns, a single composite score was developed to measure motivation to change. A second order factor structure of the four subscales was used to create a continuous measure of motivation to change, Readiness to Change (RTC), from the URICA subscales (Carbonari et al., 2001; DiClemente et al., 2001). RTC is calculated by subtracting scores on the precontemplation subscale from the sum of the contemplation, action and maintenance subscales. In Project MATCH, RTC was predictive of percent days abstinent and drinks per drinking day among aftercare patients during treatment and at each of the follow up periods (Project MATCH Research Group, 1998a; Project MATCH Research Group 1998b). Observed effect sizes for readiness to change, as measured by Cohen’s d, ranged from .06 to .35 for percent days abstinent and 0 to .26 for drinks per drinking day (Cohen, 1988; DiClemente et al., 2001; Rosnow and Rosenthal, 1996). In addition, a significant interaction between motivation and treatment was identified during the final month of a one year follow up period among outpatients (Project MATCH Research Group, 1997). Therefore, the use of RTC as a composite measure may inform clinical practice and research investigating potential mechanisms of action.

Committed Action (CA) is an alternative composite measure of motivation to change among patients seeking treatment for substance abuse problems (Pantalon et al., 2002). Many of the items from the contemplation subscale of the URICA reflect ambivalence about change and endorsement of these items may reflect a decreased likelihood of taking action to change substance use. As a result, CA is calculated by subtracting the contemplation subscale from the action subscale. Pantalon et al. (2002) demonstrated that CA had stronger predictive validity than RTC among this treatment seeking population. In that study, patients with higher CA at baseline had significantly more percentage days abstinent from both alcohol and cocaine use at follow up than those with lower baseline levels of CA (86% vs. 73%, respectively). Although CA was a significant predictor of percent days abstinent from both alcohol and cocaine, this association was modest (r=.22). Nevertheless, CA may be an alternative to RTC among treatment seeking populations who are less likely to endorse items related to the precontemplation or maintenance subscales (Pantalon et al., 2002).

Field et al. (2007) recently examined the concurrent validity of RTC and CA among patients seeking outpatient treatment for substance use disorders and concluded that RTC and CA may represent different constructs related to motivation to change. Linear regression indicated that RTC and CA were associated with different baseline characteristics. RTC was associated with anger expression (B =−.28; 95% CI =−.6, −.01) and recent life events (B = 1.1; 95% CI = .01, 2.2). CA was associated with alcohol problems (B =−.33; 95% CI =−.62, −.05) and state anxiety (B =−.13; 95% CI =−.21, −.04). On the basis of these findings, Field et al (2007) hypothesized that RTC may reflect a patient’s desire to change or seek help and CA may reflect the patient’s long term commitment to behavior change. Thus, RTC may be more likely to predict concurrent problems at the time of admission but CA may be more likely to predict treatment outcomes. RTC was significantly associated with baseline and pretreatment characteristics in another study (Blanchard et al., 2003). This is also consistent with recent findings demonstrating that CA (Pantalon et al., 2002), but not RTC, predicted treatment outcome among patients seeking treatment for substance dependence. Examination of the ability of RTC and CA to predict patient outcomes across substances of abuse may shed light on potential mechanisms of change involved in the effective treatment of drug and alcohol problems. It may also clarify the utility of RTC which was derived statistically using the factor structure of the URICA and CA which was derived based on theoretical assumptions related to the underlying theory of ambivalence and motivation to change.

Recent studies performed in the Clinical Trials Network (CTN) funded by the, National Institute on Drug Abuse (NIDA), provided an excellent opportunity to explore mechanisms of action and further examine the construct, concurrent and predictive validity of composite measures of motivation to change derived from the URICA among primary drug abusers and primary alcohol abusers. Randomized trials conducted in the CTN emphasize generalizability by conducting effectiveness trials in community-based treatment centers using heterogeneous samples of substance users. To date, there have been no other studies large and diverse enough to compare the validity of composite measures of change among different substance use groups. Results from two relevant multi-site trials conducted by the CTN have recently been reported; one evaluated a single session of Motivational Interviewing (MI) and the other evaluated three-sessions of Motivational Enhancement Therapy (MET) (Ball et al., 2007; Carroll et al., 2006). Both studies found a differential effect of treatment among drug and alcohol abusers. In the trial evaluating MI, Carroll et al. (2006) found that primary alcohol users, but not primary drug users, assigned to the single session of MI subsequently completed significantly more counseling sessions during outpatient treatment [ANOVA: F(1,175) = 8.1, p = .01, d = .56]. The positive effect of MI on treatment retention was also significant at the 84-day follow-up [F(1,154) = 3.79, p = .05, d = .32] (Carroll et al., 2006). This study also examined the effect of treatment on motivation as a potential outcome, although no treatment effect was observed (Carroll, 2006). In the trial evaluating MET, Ball et al. (2007) found that MET resulted in sustained reductions of substance use among primary alcohol users, but not primary drug users [Therapy X Weeks, F(4, 1632) 7.26, p=.01; Therapy X Phase, F(1, 1636)15.88, p=.001; and Therapy X Weeks X Phase, F(4, 1632) 13.92, p _ .001]. We hypothesized that the composite measures of motivation to change derived from the URICA, including RTC and CA, may account for the differential effectiveness of MI and MET among primary drug and alcohol users and possibly clarify findings from these two studies.

Following initial contact with the outpatient program, prospective participants met with a research assistant who explained the study and obtained written informed consent. After completing the baseline assessment, participants were randomized to treatment condition (MI vs. standard assessment; MET versus standard counseling) and then received study therapy sessions (1 in MI; 3 in MET) within a 28-day time period. All participants were re-assessed at the end of this 28-day period (1-month) and again 84-days (3-months) later.

There was also some evidence supporting the concurrent validity of RTC, a composite measure of motivation to change derived from the URICA. However, the observed associations were contrary to our expectations. The current hypothesis was generated on the basis of observed differences in associations between RTC and CA with baseline characteristics (Field et al., 2007). In that study, RTC was significantly associated with less anger and a greater number of stressful life events during the last year. In contrast, CA was associated with fewer alcohol problems and decreased anxiety (Field et al., 2007). Field et al. (2007) hypothesized that RTC may reflect the patient’s desire to change or initiate help seeking behavior but CA may be a better indicator of a patient’s long term commitment to behavior change. Thus, we hypothesized that RTC would predict recent psychosocial problems and substance use while CA would predict substance use outcomes (Field et al., 2007). In contrast to the prior study, the present study found a positive association as opposed to a negative association between RTC and problems associated with drug or alcohol dependence. With the exception of family problems among patients with drug dependence, increased RTC was associated with increased problems in a number of areas assessed by the ASI. RTC was also associated with increased therapeutic alliance from both the patient’s and therapists’ perspective. This would suggest that increased motivation to change is associated with more drug and alcohol problems and a stronger alliance between the client and therapist. A stronger therapeutic alliance may be influenced by the mutual expectations of the therapist and client that more severe problems should be associated with increased motivation to change, if only temporarily. Alternatively, the difference in study findings may be a function of convenience sampling procedures used in the prior study and the greater representativeness of the current study. Given that these are the strongest observed associations, this possibility may warrant further study.

The predictive validity of CA and RTC on treatment outcome was not confirmed. In our prior study we speculated that, because of its association with significant problems and distress, CA would be a stronger indicator of treatment outcome (Field et al., 2007). Contrary to this hypothesis, CA was not associated with primary drug use or treatment retention at follow up for either group of patients. Our findings also suggest that RTC explains only a small percentage of the variance in patient outcomes. In the case of treatment retention among patients with drug dependence, the association was in the opposite direction to that previously observed by Field et al. (2007), i.e., increased RTC at baseline associated with fewer days in treatment. A possible explanation is that patient’s perception of motivation to change subsequent behavior could be overly optimistic and these inaccuracies may lead to poor predictive validity.

We found no evidence of a moderating or mediating effect of either composite measure on treatment outcomes among patients with primary drug or alcohol use problems. Baseline measures of motivation to change did not appear to moderate treatment outcomes even after controlling for treatment assignment or a possible interaction between treatment assignment and motivation to change. Prior research indicated that motivational based interventions were particularly useful with clients who were less motivated or ready for change (Project Match Research Group, 1997). However, the current evidence suggested that the effectiveness of treatment was not dependent on the patient’s initial motivation to change. Thus, motivation to change as measured by the composite measures of motivation derived from the URICA did not facilitate interpretation of the findings from the parent studies (Ball et al., 2007; Carroll et al., 2006). While these measures of motivation have been found to have predictive validity in prior studies, the association between motivation and subsequent behavior has been relatively weak and inconsistent. For example, in Project MATCH, RTC accounted for 3% of the variance in drinking outcomes during treatment and at 3-year follow up (Project MATCH Research Group, 1998a; Project MATCH Research Group, 1998b). Similarly, CA accounted for only 5% of the variance in percent days abstinent (Pantalon et al., 2002). Thus, the current findings reflect generally weak associations between motivation to change and actual patient behavior following treatment.

To the extent that motivation to change assessed at intake reflects behavior that occurred prior to completing the assessment, any association with outcome may reflect changes in the client that occurred prior to treatment (Project MATCH Research Group, 1998a). There is some evidence from the current study that suggest that this may be the case. Increased RTC at intake among drug users was associated with fewer days use during the past 28 days and fewer family problems while CA at intake was associated with fewer days use and less severe alcohol problems among patients with primary alcohol dependence. CA was also associated with less severe problems associated with addictive disorders at intake among patients with primary drug problems. In contrast, RTC at intake was significantly associated with more problems. Alternatively, motivation to change at intake may be less important than what actually happens during treatment (Simpson and Joe, 1993). However, the current findings also suggested that motivation following intervention did not appear to mediate treatment outcomes. This was a particularly noteworthy finding given that one of the explicit functions of motivational interviewing and its variants is to increase motivation to change (Miller and Rollnick, 2002). The cumulative evidence supporting the effectiveness of Motivational Interviewing and its derivatives is overwhelming in comparison to non-active treatments (Miller et al., 2003). Moreover, Motivational Enhancement Therapy is equally efficacious as Twelve Step Facilitation and Cognitive Behavior Therapy (Project Match Research Group, 1997). It may be that motivation to change, as measured by the composite measures of readiness to change derived from the URICA, was not relevant to treatment outcome. Thus, while the URICA appeared to conform to the a priori theoretical model for patients with both primary drug and alcohol problems, it had limited utility for explaining differences in treatment outcome or understanding underlying mechanisms of change.

In the same way that the lack of association between changes in cognition and treatment should not lead to doubts regarding the overall effectiveness of CBT (Morgenstern and Longabaugh, 2000), the current results should not lead to doubts regarding the utility of motivational interviewing. Rather, the theoretical assumptions underlying the effectiveness of motivational interviewing and other evidenced-based treatments for substance abuse should be further examined. Because of the limitations of measures of motivation including the URICA and the transtheoretical model in general, some have argued for abandoning the transtheoretical model and related concepts (Sutton, 2001; West, 2005). The current study does provide some support for their observations and criticisms. Most notably, as observed by Sutton (2001) the elevated correlations among the subscales and the latent variables representing the stages of change are highly correlated and suggest that they may not be discrete or qualitatively distinct. Moreover, precontemplation is negatively correlated with contemplation, action and maintenance. This is more consistent with the calculation of RTC, which substracts precontemplation from the subtotal of contemplation, action, maintenance to measure readiness, than the calculation of CA, which subtracts contemplation from action. Since contemplation and action are positively correlated there may be limited utility in the use of CA as a measure of readiness. However, it is worth noting that the calculation of RTC was derived statistically and the development of CA was theoretically driven. However, the current study does not assess the Transtheoretical Model as a whole, or the Stages of Change, in particular. The current study is focused on the potential usefulness of the composite measures of motivation to change derived from the URICA. It is possible that motivation to change effects treatment outcome through another mechanism such as the processes of change or therapeutic alliance. However, no evidence regarding such causal chains were identified in Project MATCH (DiClemente et al., 2001). Perhaps other process oriented measures can provide better insight into the client and therapists contribution to behavior change which may, in turn, lead to a better understanding of the mechanisms of change underlying evidenced-based treatments. For example, examinations of the impact of therapist communication on client speech might prove more fruitful in understanding patient outcomes. Miller and colleagues (Miller et al., 2008) have developed coding procedures to assess client commitment. Moyers and Martin (2006) have explored therapeutic interactions and found significant associations between therapist behaviors and client commitment to change. Moyers et al. (2007) have also demonstrated that client speech may be powerful predictors of treatment outcomes. In addition, proximal measures of the interactions during treatment using motivational interviewing may result in a better understanding of the active ingredient of this and other approaches.