Translation and validation of the “personal evaluation of transitions in treatment (PETIT)” scale for people with schizophrenia

Abstract

Aims. To adapt the ‘Personal Evaluation of Transitions in Treatment (PETIT)’ scale into Spanish and analyse its psychometric properties on schizophrenic population.

Method. 223 patients in outpatient treatment diagnosed with schizophrenia according to DSM-5 criteria participated in the study. A defined variable ‘therapeutic compliance’, DAI10 and SMAQ were used as a gold standard and the psychometric properties of the scale were analysed at three time points (baseline, 1 month and 6 months).

Results. The scale has very high face (or logical) validity. Exploratory factor analysis showed it would be necessary to eliminate item 7. The reliability of the scale is high (Cronbach’s alpha = 0.91), demonstrating good internal consistency. After eliminating item 7, confirmatory factor analysis obtained 5 components that explained 57,76% of the variance. The content of the scale is valid for discriminating between patients of different treatment adherence, response and quality of life. The cut-off point of the ‘PETIT’ scale in Spanish is set at 24 points for both sexes, with good sensibility to change and very good concordance force over the three time points evaluated.

Conclusions. After eliminating item 7 and using ‘24’ as cut-off point, the ‘PETIT’ scale was able to detect changes in both adherence and response to treatment as well as the resulting modifications to the quality of life of patients. Its use as a single instrument to measure all of the above makes it advisable for use in clinical practice, as the evaluation methods it requires are relatively simple and quick to perform.