An investigation of fear of the dark in individuals with insomnia disorder

Past research found that individuals with poor sleep report and physiologically exhibit greater fear of the dark (FOD) than good sleepers (Carney et al., 2013). The presence of FOD in individuals with insomnia disorder (ID) would have important implications to our understanding of ID and its treatment. Thus, the present study compared individuals with ID to good sleepers (N = 50) on objective and subjective FOD, and explored the FOD construct through participant interviews. Contrary to expectations, ID and good sleeper groups did not differ on FOD measures. Cognitive arousal and trauma history were related to reported dark discomfort. For those with ID, experiences in the dark were characterized by greater sleep effort and pre-sleep arousal generally, but not dark-specific fear per se. For those who were fearful of the dark we posit that there may be a trauma-activated pathway to arousal. Implications and avenues for future research are discussed.