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.