Objective: To determine the prevalence of insomnia and posttraumatic brain injury (TBI) fatigue (PTBIF) in individuals with moderate to severe TBI, to explore the relationship between PTBIF and insomnia and their association with outcomes.
Design: Cross-sectional study.
Setting: Five National Institute of Disability and Rehabilitation Research TBI Model Systems.
Participants: Three hundred thirty-four individuals with TBI who completed 1-year (n = 213) or 2-year (n = 121) follow-up interviews between 2008 and 2012.
Main outcome results: Insomnia occurred in 11% to 24% and PTBIF in 33% to 44% of the individuals. Insomnia and fatigue were both related to sleep disturbance, sleep hygiene, satisfaction with life, anxiety, and depression. PTBIF was associated with greater disability and sleepiness. Insomnia without fatigue was rare (2%-3%) but PTBIF without insomnia occurred in 21% to 23% of the individuals. Comorbidity occurred in 9% to 22% of the individuals.
Conclusions: Although PTBIF and insomnia are closely related and both associated with poorer quality of life, they are affected independently by a variety of factors, especially psychopathology and sleep quality. A majority of individuals with PTBIF do not have insomnia; and PTBIF appears to be related to disability severity and daytime sleepiness, where insomnia is not. Demographic and injury variables are not strong predictors of insomnia or PTBIF.