Abstract Background In Portugal, as far as we know, there are no recent studies that evaluated the comparative efficacy of therapeutic modalities in addiction problems by reference to a holistic and psychosocial model of effectiveness. Objectives Using a sample of Portuguese patients in outpatient treatment for drug and alcohol abuse, this study aimed to examine if a combined treatment modality (group therapy with individual intervention) had greater overall efficacy when compared to other three types of treatment without group therapy. Methods This is a correlational and cross-sectional study using a convenience sample of patients (N = 254) from an outpatient treatment in the Intervention Service on Addictive Behaviors and Substance Dependence. At the time of data collection, the patients were attending four types of treatment, such as receiving intervention based on individual psychological counseling (n = 66); receiving individual psychiatric counseling (n = 68); receiving both individual psychological and psychiatric counseling (n = 102); and receiving not only individual counseling (i.e., psychology or psychiatry), but also attending group therapy (n = 18). Results Using MANOVA and Wilks’s multivariate test criterion, there was a significant effect of treatment modality on the global efficacy, Λ = 0.88, F(9, 603) = 3.75, p < 0.0001. Examination of mean estimates indicated that patients in a combined therapeutic modality revealed more treatment involvement compared to patients in other therapeutic modalities without group therapy. Discussion The results obtained in this study highlight the importance of integrating interventions in a collaborative way. A combined therapeutic modality, adding group therapy, was associated with positive effects, such as more levels of peer support and involvement in treatment, and increasing the individual’s probability to remain abstinent.

Background Practitioners need brief instruments to monitor outcomes in both treatment of drugs and alcohol addiction because they are useful to guide decision making in a short time.Objectives This study aims to develop a brief questionnaire, based on Client Evaluation of Self and Treatment, to evaluate the treatment effectiveness in drug and alcohol addiction treatment settings.Methods A cross-sectional study using a convenience sample (N = 608) recruited from Division for Intervention on Addictive Behaviours and Dependencies (DICAD – ARS North).Results The results show a new four-factor solution that accounted for 54.4% of the total variance and that provides the best fit to the data (c2/df = 1.72, CFI = .94, GFI = .91, RMSEA = .048 [.040-.057]; prmsea = .623). It also revealed a high internal consistency (a = .82). It was found a significant negative correlation (r = - .52, p < .01) between the final version of the instrument and a self report measure of psychopathology symptoms.Discussion This brief questionnaire, with good psychometric properties, can be useful to provide a viable and rapid feedback of treatment outcomes. Further studies should be performed to continue the evaluation of the reliability of this measure.