Somatic symptoms are associated with Insomnia disorder but not Obstructive Sleep Apnoea or Hypersomnolence in traumatic brain injury

BACKGROUND Previous studies examining insomnia in populations with traumatic brain injury (TBI) have not distinguished between transient insomnia symptoms and insomnia disorder and associations have been confounded by other highly prevalent sleep disorders post-TBI. OBJECTIVE To investigate the associations between affective symptoms and somatoform symptoms in patients with TBI and insomnia, sleep apnoea and hypersomnolence. METHODS Twenty-four participants from a multidisciplinary brain injury rehabilitation service with TBI were assessed for insomnia disorder, using Diagnostic and Statistical Manual Fifth Edition (DSM-5) criteria. Associations with affective and somatic symptoms were assessed, using the DASS-21 and PHQ-15 respectively. The same cohort was divided for Obstructive Sleep Apnoea (OSA) and hypersomnolence and analysed for the same outcomes. Associations were assessed using Pearson's correlation and a logistic binary regression model was developed to predict insomnia in patients with brain injury. RESULTS The insomnia disorder group (n = 11) had significantly higher rates somatoform symptoms (p