Subjective Well-Being Under Neuroleptics Scale short form (SWN-K): reliability and validity in an Estonian speaking sample

BACKGROUND: The Subjective Well-Being Under Neuroleptic Treatment Scale short form (SWN-K) is a self-rating scale developed to measure mentally ill patients' well-being under the antipsychotic drug treatment. This paper reports on adaptation and psychometric properties of the instrument in an Estonian psychiatric sample. METHODS: In a naturalistic study design, 124 inpatients or outpatients suffering from the first psychotic episode or chronic psychotic illness completed the translated SWN-K instrument. Item content analysis, internal consistency analysis, exploratory principal components analysis, and confirmatory factor analysis were used to construct the Estonian version of the SWN-K (SWN-K-E). Additionally, socio-demographic and clinical data, observer-rated psychopathology, medication side effects, daily antipsychotic drug dosages, and general functioning were assessed at two time points, at baseline and after a 29-week period; the associations of the SWN-K-E scores with these variables were explored. RESULTS: After having selected 20 items for the Estonian adaptation, the internal consistency of the total SWN-K-E was 0.93 and the subscale consistencies ranged from 0.70 to 0.80. Good test–retest reliabilities were observed for the adapted scale scores, with the correlation of the total score over about 6 months being r = 0.70. Confirmatory factor analysis replicated the presence of a higher-order factor (general well-being) and five first-order factors (mental functioning, physical functioning, social integration, emotional regulation, and self-control); the model fitted the data well. The results indicated a moderate-high correlations r = 0.54 between the SWN-K-E total score and the evaluation how satisfied patients were with their lives in generally. No significant correlations were found between the overall subjective well-being score and age, severity of the psychopathology, drug adverse effects, or prescribed drug dosage. CONCLUSION: Taken together, the results demonstrated that the Estonian version of the SWN-K is a reliable and valid instrument with psychometric properties similar to the original English version. The potential uses of the scale in both research and clinical settings are considered.