Spirituality is widely believed to play an important role in securing health, and modern health care is increasingly being combined with spiritual care. This state of affairs is generating widespread interest in the construct from practitioners and researchers, resulting in the need to develop accurate and comprehensive measures of spirituality. The purpose of this study was to adapt the Polish version of the Interfaith Spirituality Scale (IFS), which consists of twenty-two statements, as well as its short version, including four statements. The IFS is not limited to any one religious denomination, making it possible to conduct research across diverse communities. The analyses were conducted on a sample of 642 Poles aged 18-68, 48% of whom were women. The Polish version of the scale showed high internal consistency (α = 0.96 for the IFS and α = 0.81 for the short version). Confirmatory factor analysis showed that the structure of the IFS consists of a unitary second-order factor with four first-order factors (direct connection with the creator, asceticism, meditation, and divine love). On the other hand, the structure of the short version is unifactorial. There were positive correlations of the IFS with another measure of spirituality, post-traumatic growth severity, mental well-being, and ecological behaviour, as well as negative correlations with post-traumatic stress disorder symptom severity and depressiveness; these confirmed the high validity of the tool. The results suggest that the IFS may be useful in the study of spirituality on Polish soil.
Keywords: IFS; interfaith spirituality scale; polish adaptation; spirituality scale.