Fear of Sleep Inventory- Short Form (FoSI-SF): A validation study for Turkish speaking populations

Abstract

Fear of sleep is an emerging construct that is connected to the pathogenic mechanisms underlying sleep disorders in individuals with traumatic experiences. The present study aimed to examine the factor structure and psychometric qualities of the Turkish version of the Fear of Sleep Inventory Short Form (FOSI-SF; Pruiksma et al. Journal of Clinical Sleep Medicine, 10(05), 551–558, Pruiksma, K. E., Taylor, D. J., Ruggero, C., Boals, A., Davis, J. L., Cranston, C., DeViva, J. C., & Zayfert, C. (2014). A Psychometric Study of the Fear of Sleep Inventory-Short Form (FoSI-SF). Journal of Clinical Sleep Medicine, 10(05), 551–558. 10.5664/jcsm.3710). A total of 420 adults aged between 18–68 (177 female; M = 41.03, SD = 15.02) responded to the online survey. In addition to FoSI-SF, participants responded to scales measuring insomnia, repetitive negative thinking, anxiety, depression, and PTSD symptoms. Different from the original two-factor structure of FoSI-SF, the Turkish version yielded three factors as fear and threat perception, vulnerability and hypervigilance, and fear of darkness. FoSI-SF Turkish and its subscales displayed satisfactory levels of internal consistency and significant correlations with measures of insomnia, repetitive negative thinking, and psychopathology as indicative of convergent validity. Moreover, FoSI-SF had significant associations with insomnia symptoms only among the participants who had clinically significant levels of PTSD. Overall, the results indicated the Turkish version of FoSI-SF to be a reliable and valid measurement tool for the assessment of fear of sleep.