Abstract
This secondary data analysis of the Clinical Trials Network's Motivational Enhancement Therapy effectiveness trial with Spanish-speaking substance users examined whether the degree of birthplace and acculturation similarities between clients and therapists, as well as the therapists' own level of acculturation and birthplace were related to the clients' participation in treatment and level of substance use during outpatient substance use treatment. Sixteen therapists and their 235 clients from the larger effectiveness trial were included in the analyses for this study. Results of the multilevel regression models for client participation in substance use treatment and client days of substance use, taking into account within and between therapist cultural characteristics, revealed that birthplace match and acculturation similarity between each therapist and his or her clients did not predict client outcomes. Instead, therapists' birthplace and level of acculturation independently predicted days of substance use, but not treatment participation for monolingual Spanish-speaking clients. These findings are discussed in the context of the results of the main effectiveness trial and of psychotherapy research with ethnic minority populations, in particular Hispanic minorities.
