Chronic insomnia - beyond the symptom of insufficient sleep

Chronic insomnia is the most common sleep disorder, affecting up to 10% of the global population, with more than one-third of the individuals worldwide reporting insufficient sleep as a common complaint. Due to its high prevalence, insomnia frequently co-exists with various somatic and psychiatric disorders, exhibiting a bidirectional relationship in which each condition influences the other. Depression, anxiety, cardiovascular diseases, and malignancies can serve as factors triggering insomnia complaints, according to the behavioral model for insomnia development. Moreover, chronic insomnia increases the risk of these diseases through several pathogenic mechanisms, including activated stress response, altered neurotransmitter signaling, and impaired emotion regulation. This interplay creates a vicious cycle of poor sleep, deteriorated health, and impaired quality of life. Recognizing the relationship between insomnia and overall well-being is essential for adopting optimal treatment methodology, as addressing insomnia can ameliorate associated mental and physical health issues. This review explores the bidirectional association of chronic insomnia with other somatic and mental diseases, illustrating how each can aggravate the other, and emphasizes the importance of effective insomnia management in improving overall health and quality of life.