Examining insomnia subtypes in patients with co-morbid insomnia and sleep apnea

Objectives: Recent research suggests that Co-morbid Insomnia and Sleep Apnea (COMISA) is highly prevalent and debilitating. It is also a heterogeneous disorder, requiring tailored diagnostic and treatment approaches. For example, COMISA patients with Difficulties Initiating Sleep (DIS) are thought to have different underlying mechanisms, and require different treatment approaches, compared to patients with Difficulties Maintaining Sleep (DMS). It is important to better understand the specific characteristics of each subtype to tailor and optimise insomnia treatment. Methods: Participants included 115 COMISA patients (ICSD-2).Participants were divided into those with DIS (average sleep onset latency >30 min), DMS (average wake after sleep onset >45 min), or Difficulties Initiating and Maintaining Sleep (DIMS; both criteria). The following symptoms were compared between groups; daytime impairments, daytime sleepiness, dysfunctional beliefs about sleep, anxiety, stress, and depression. Results: 17 participants had DIS, 39 had DMS, and 59 had DIMS. Patients with DIS reported greater daytime impairments than patients with DMS or DIMS, and increased depression, anxiety, and dysfunctional beliefs about sleep compared to patients with DMS. Patients with DMS reported lower stress than patients with DIS or DIMS. No significant group-differences in daytime sleepiness were found. Conclusions: It is suggested that COMISA patients with DIS and DMS require different treatment approaches. These results suggest that patients with DIS suffer greater daytime impairments, increased symptoms of depression, anxiety and stress, and greater dysfunctional cognitions, compared to patients with DMS. COMISA patients with DIS appear to experience psychophysiological insomnia, which may negatively impact PAP treatment responses. Disclosure: Research Funded by NHMRC Grant: 104