Comorbid insomnia in sleep-related breathing disorders: an under-recognized association

In the clinical practice of sleep medicine, the coexistence of common sleep disorders is not uncommon. Patients with sleep disordered breathing (SDB) may present with insomnia, and studies have shown that SDB is common among insomnia patients. Little is known about the pathophysiological mechanisms underlying this coexistence, and limited information is available regarding the impact of each disorder on the other. It is essential to consider the effect of each disorder on the other and to understand the clinical consequences anticipated when treating each disorder in isolation. The management plan should be directed toward both disorders in a systematic and evidence-based approach. Unfortunately, a consensus standard approach for the management of comorbid insomnia and SDB is not yet available. Therefore, we have reviewed published studies that investigated insomnia in patients with different types of SBD; obstructive sleep apnea, central sleep apnea, and hypoventilation syndromes, as well as studies that assessed SBD in patients with insomnia. In addition, we reviewed the effects of SBD treatment modalities on insomnia and the effects of insomnia treatments on SBD.