Adolescent Nocturnal Fears: a psychometric evaluation of the fear of sleep inventory (FoSI)

Objective: Nocturnal fears are associated with trauma-related sleep disturbance in adults, yet research is limited addressing this relationship in adolescents. This study evaluated the validity of the Fear of Sleep Inventory (FoSI) as a measure of nocturnal fears broadly and in relation to trauma exposure in adolescents. Participants: Students ages 14–18 from two urban school-based health centers were the participants. Methods: De-identified clinical data were utilized from a mental health screening battery. Two exploratory factor analyses (EFA) were conducted using the full 23-item FoSI and the 13-item short form. Cronbach’s α and Pearson correlation coefficients were employed to examine the convergent and divergent validity of the total scores and the factors derived from the EFA with Insomnia Severity, probable PTSD, and parental monitoring respectively. Results: The 23-item FoSI showed high internal consistency (α = .84); however, EFA yielded an unclear factor structure. Further analysis indicated that an 11-item FoSI yielded a clear 2-factor structure with subscales conceptualized as (a) Fear of Sleep and (b) Vigilant Behavior. Conclusions: The FoSI-11 demonstrates promise as a measure of nocturnal fears in adolescents and can help reveal distinctions between trauma-related nocturnal fears and nocturnal fears associated with psychological or environmental factors. It can be utilized as a screener to highlight adolescent nocturnal fears in large group settings, while also identifying individuals in need of further assessment of trauma exposure. Future studies should include the FoSI-11 to provide a more thorough examination of the role of adolescent nocturnal fears in the relationship between trauma and sleep disturbance.