Sleep disturbances: Definitions, prevalence, and associations to mental disorders

Sleep medicine is a young field. Since the first effort to classify sleep problems 25 years ago, the epidemiology of sleep disorders has progressed considerably. From the assessment of the mere presence of symptoms, the epidemiologic evaluation of sleep disturbances has evolved to more structured criteria. This evolution has had a direct consequence on the evaluation of the prevalence of sleep disturbances and sleep disorders. It also has impacted public awareness about different sleep disorders. However, considerable public health efforts remain. Most of the large epidemiologic studies include only a limited number of questions related to sleep, preventing the possibility of making differential diagnoses or adequately evaluating the risk factors associated with sleep symptoms, syndromes and disorders. Sleep disturbances appear to place the general population at risk for depression and other mental disorders and increase the risk of relapse in those treated for mental disorders, but further exploration of this relationship is needed. There is a clear need for early identification and treatment of sleep disturbances in the general population. It is imperative that epidemiologic studies focus on factors that could help health care practitioners recognize the different sleep disorders.