Neurobiological Correlates of Psychological Treatments for Insomnia A Review

Sleep disorders and sleep disturbances are considered nowadays a major public health problem. Within sleep problems, insomnia is the most common health complaint. The maintenance of insomnia symptoms may lead to a clinical disorder - Insomnia Disorder (ID). A significant amount of literature has shown the efficacy and effectiveness of psychological treatments for ID. Often, the evaluation of therapeutic processes and outcomes focuses on subjective measures such as sleep diaries. In this work, we review the few published studies that evaluate modifications in neurobiological domain related to evidence-based psychological interventions, namely cognitive-behavioral therapy for insomnia (CBT-I). The search was carried out consulting Scopus, PubMed, and ISI Web of Knowledge databases. Only 12 studies were found. From the reviewed papers it was observed that the results are diverse, perhaps due to significant differences pertaining to the methodologies used. However, one interesting finding emerged: daytime experiments on insomnia comprising mainly cognitive tasks denoted hypofunction in ID patients, whereas nighttime experiments mainly associated with affective/emotional tasks denoted hyperarousal. We suggest that the study of the neural changes prompted by CBT-I is a major topic in the domain of psychotherapy and sleep medicine. Despite the scarce studies on neurobiological mechanisms of CBT-I, the results achieved until now are promising and should be taken into account in the future. Nonetheless, more research on this topic is needed.