Why Insomnia and Sleep Apnea Often Occur Together and Their Effects

The combination of chronic insomnia and obstructive sleep apnea forms a complex disorder called COMISA. This condition affects about 30% of the general population, with a higher frequency among those aged 18-40 and in Europe. Affected individuals have a higher apnea-hypopnea index, lower nighttime oxygen saturation, more frequent nocturnal awakenings, and impaired sleep quality. Their sleep is less restorative, with longer sleep onset and often reduced deep sleep phases.

The underlying mechanism involves an interaction between the two disorders. Sleep apnea causes repeated micro-arousals to restore breathing, which can trigger or worsen maintenance insomnia. Conversely, insomnia, by increasing brain wakefulness, makes the airways more unstable and promotes apneas. This vicious cycle is self-sustaining and deteriorates sleep structure. Awakenings are longer and more frequent, and the subjective perception of sleep quality is often worse than what objective tests show.

The consequences extend beyond daytime fatigue. People with COMISA are more likely to suffer from psychiatric disorders such as anxiety or depression. Their average body mass index is often high, which can worsen both conditions. Standard apnea treatments, such as continuous positive airway pressure, are less effective if insomnia is not addressed simultaneously. An approach combining cognitive-behavioral therapy for insomnia and apnea management is therefore essential to break this cycle and improve overall health. Prevalence varies by region, with higher rates in Europe, suggesting genetic, cultural, or environmental influences. Personalized and integrated care remains key to mitigating the risks associated with this comorbidity.

Information and Sources

Scientific Reference

DOI: https://doi.org/10.1007/s11325-026-03631-0

Title: Physiopathological correlations of comorbid insomnia and sleep apnoea (comisa) – a systematic review and meta-analysis

Journal: Sleep and Breathing

Publisher: Springer Science and Business Media LLC

Authors: Ervin Cotrik; Janete Hernandes; Viviane Castro; Edilson Zancanella