The Predictive Validity of the Dual Diagnosis Capability in Addiction Treatment (DDCAT) Index

Abstract

Objective: The study examined the degree to which licensed outpatient substance abuse treatment programs were capable of delivering integrated services for individuals with co-occurring substance use and psychiatric disorders. Aggregate measures of client retention were also obtained, and their relationship with capability scores was explored. Methods: The co-occurring or dual diagnosis capability of each program was measured with the Dual Diagnosis Capability in Addiction Treatment (DDCAT) index, a 35-item rating tool organized into seven dimensions that categorizes programs along a continuum where 1 = addiction-only services, 3 = dual diagnosis–capable, and 5 = dual diagnosis–enhanced. Admission and discharge data were obtained from a state regulatory agency database for clients with co-occurring disorders who received services from state-licensed outpatient substance abuse clinics and who had been discharged from treatment over a 6-month period defined as the 3 months before and after the DDCAT assessment. Admission and discharge data were then aggregated to the program level and their relationship with the DDCAT data was examined. Results: A total of 185 state-licensed outpatient substance abuse clinics were included in the analysis. Generalized linear models showed a significant positive relationship between DDCAT scores and length of stay (odds ratio = 1.209; p < .001), which indicated that clients with co-occurring disorders stayed longer in treatment programs with higher DDCAT scores. Analyses also demonstrated that five DDCAT dimensions were significantly related to length of stay (odds ratios ranged from 1.057 to 1.155; p < .01); the two exceptions were the screening/assessment and treatment dimensions. Conclusions: Given that prior research established treatment retention as a predictor of long-term outcomes, such as relapse to drug use, this study represents an important first step toward validating the DDCAT. Further validation of the DDCAT should consider incorporating a broader range of treatment quality indicators and client outcomes.