The study, with a clinical sample (N=147), presents the internal consistency, factorial structure, concurrent and predictive validities of the Portuguese version of the Stages of Change Scales-SCS. The psychometric properties of the scales, a 32 item self-report instrument, are compared to those of two studies with the English version. Results point to a factorial structure compatible with that of the original version, which evaluates four stages of change: precontemplation, contemplation, action and maintenance. Adaptations, of at least four items of the precontemplation and contemplation stages, are required to improve the internal consistency coefficients, lower than those of the original studies. The weak association between the SCS and the Escala Diagnóstica Adaptativa Operacionalizada-Redefinida - EDAO-R suggests the criterion unsuitability to the concurrent validity. Based on the SCS scores, results do not allow to predict which patients are more suitable to conclude brief psychotherapies. New researches are suggested.
transtheoretical model of change; clinical assessment; brief psychotherapy
