Preliminary data concerning the reliability and psychometric properties of the Greek translation of the 20-item Subjective Well-Being Under Neuroleptic Treatment Scale (SWN-20)

Translation and cross-cultural adaption of an instrument measuring patient's well-being under treatment for schizophrenia

OBJECTIVES

The Subjective Well-Being under Neuroleptic (SWN) Scale is a self-rating scale measuring the well-being of patients with schizophrenia under antipsychotic drug treatment. The instrument has been globally used, with issues regarding the well-being assessment scale across different cultures, patient characteristics, and country-setting remains a controversy. This study aimed to translate and culturally adapt the SWN scale into the Indonesian version (Indonesian Modified SWN or IM-SWN) and evaluate its validity and reliability.

METHODS

The SWN instrument was translated and culturally adapted following internationally accepted procedures, including forward translation, expert panel review, backward-translation, pretesting and cognitive interviewing, and psychometric analysis for the final version of the scale. The translated instrument was tested on 108 schizophrenia patients. The instrument's validity and reliability were assessed using Pearson's correlation and Cronbach's Alpha coefficient. Additional analysis for the socio-demographic and psychometric properties of the patient was also conducted.

RESULTS

The range of IM-SWN total score between 30 and 112. IM-SWN was found to have a high-reliability coefficient (0.897), and the internal consistency values of each question item ranged between 0.885 and 0.910. The results also showed a high correlation between five order factors (Physical functioning, mental functioning, self-control, emotional regulation, and social integration), with a total score of between 0.768 and 0.885.

CONCLUSIONS

This study highlighted that the IM-SWN is a valid and reliable instrument for measuring well-being among the Indonesian population with schizophrenia.

Refinement of the SWN-20 based on the Rasch rating model

OBJECTIVES

The aim of the present study was to refine the 20-item Subjective Well-Being under Neuroleptic Treatment Scale (SWN-20) using the Rasch rating model to validate measurements of subjective well-being in patients with schizophrenia undergoing antipsychotic treatment.

METHODS

In total, 854 (403 males, 451 females) inpatients (n=213) and outpatients (n=641) with schizophrenia participated in this study, which was designed as an open-label investigation of paliperidone extended release. The participants completed the Korean version of the SWN-20 themselves. Refinement of the Korean version of the SWN-20 was accomplished using the Rasch rating model.

RESULTS

Infit and outfit statistics for all 20 items satisfied the criterion for construct validity. Second, all items except items 2 and 20 had suitable point-measure correlations, reflecting content validity. Third, item characteristic curves indicated that roughly 18 items were evenly distributed along the person ability continuum. Finally, option analysis of the category characteristics showed that categories 3 and 4 in the SWN-20 response format were unnecessary.

CONCLUSIONS

We offer several recommendations for improving the SWN-20: (a) items 2 and 20 should be omitted to ensure construct validity; (b) easier items would be added related to the person ability estimates in the process of validating a short form of the SWN scale based on item response theory; and (c) the number of response categories should be reduced for schizophrenic patients.

Psychometric evaluation of the Subjective Well-being Under Neuroleptic Treatment Scale (SWN) in patients with schizophrenia, their relatives and controls

The objective of this study was to evaluate the psychometric properties of the 20-item version of the Subjective Well-being Under Neuroleptic Treatment Scale (SWN) in patients, their siblings and parents and in healthy controls. In order to study heritability of subjective well-being, assessment in unaffected relatives and healthy controls is necessary. Data were obtained from the Dutch GROUP study (Genetic Risk and Outcome of Psychosis), a large cohort study on non-affective psychotic disorders incorporating patients, their relatives and healthy controls. The SWN scale and other relevant assessments were completed by 545 schizophrenia patients, 541 siblings, 75 parents, and 280 healthy controls. Reliability within the four groups ranged between Cronbach's alpha 0.88 and 0.92. Factor analysis indicated a single factor structure of the SWN scale, which makes only SWN total scores relevant.The WHO-Quality of Life psychological domain correlated highly with SWN total scores in all groups. Subclinical psychotic experiences were found to be associated with SWN total scores in relatives and healthy controls, supporting the psychosis continuum concept. The 20-item SWN scale is a reliable measure for subjective well-being that can also be used in relatives and healthy controls to investigate genetic and psychological dispositions of subjective well-being.

Subjective well-being in schizophrenia as measured with the Subjective Well-Being under Neuroleptic Treatment scale: a review

OBJECTIVE

The Subjective Well-being under Neuroleptic Treatment scale (SWN) is the most widely used self-rating scale in recent research of subjective well-being in schizophrenia. We reviewed all available publications on relevant research of subjective well-being using the SWN, in order to evaluate measurement of subjective well-being with a single instrument.

METHOD

A MEDLINE and Embase search was performed for studies published between January 1994 and August 2010, analysing controlled and open clinical trials using the SWN.

RESULTS

A total of 52 publications were identified covering 44 studies. Strong evidence exists for improvement of subjective well-being during treatment. Atypical antipsychotics are associated with a higher level of well-being. However, dosage is more important than the kind of medication. Striatal dopamine D(2) receptor occupancy is correlated with subjective well-being. Early positive response of subjective well-being is predictive of a better outcome. Research on determinants of subjective well-being is rapidly expanding, focusing mostly on the effects of medication.

CONCLUSIONS

Subjective well-being of schizophrenia patients is a valuable outcome measure. It can be improved by optimizing antipsychotic treatment. More research on psychological and genetic predictors of subjective well-being is needed.