Validity of the Spanish version of the Personal and Social Performance scale in schizophrenia

Abstract

Background The Personal and Social Performance (PSP) scale is a reliable and valid instrument that utilizes objective parameters for the assessment of social functioning in patients with schizophrenia. Objective The aim of this study was to determine the validity and reliability of the Spanish version of the PSP scale. Method In total, 100 patients with DSM-IV diagnoses of schizophrenia and schizoaffective disorder were recruited and assessed with the PSP, the GAF, the PANSS, and the CGI. Internal consistency for the PSP was obtained and discriminant validity was assessed by comparing PSP scores between inpatients and outpatients; correlations between PSP scores, the GAF, and the five factors of the PANSS were used to evaluate the convergent validity of the scale; reliability was evaluated with intra-class correlation coefficients and temporal stability was obtained using correlation coefficients between the PSP and CGI scores on a follow up assessment. Results The Cronbach's alpha coefficient of the PSP was 0.843. Inpatients showed lower scores on the PSP than did outpatients. Patients with low scores on the PSP reported fewer years of education, were more frequently unemployed, had a longer duration of illness, and had a shorter duration of antipsychotic treatment. The PSP scores showed a positive correlation with the GAF and a negative correlation with the cognitive, negative, and positive factors derived from the PANSS. The PSP scores showed significant correlations with the severity and improvement CGI scores at follow-up. Good inter-rater reliability was obtained. Conclusion These findings support the Spanish version of PSP to be a reliable and valid instrument for the assessment of social functioning in patients with schizophrenia.