Antidepressant effect of non-pharmacological chronotherapy in the treatment of depression

Antidepressants are the main treatment for depression. However, application of pharmacotherapy is often connected with some limitations. In the last decades growing evidence has been accumulated pointing to a role of dysregulated biological rhythms in functional pathology of depression. That is why interest in chronobiological interventions is increasing. Chronotherapy is based on the principles of circadian rhythm organization. Chronotherapeutics in depression can be defined as controlled exposure to environmental stimuli that act on biological rhythms in order to achieve the appropriate day-night cycle, as well as restoration and synchronization of neuroendocrinal, physiological and cognitive factors. Chronotherapy for depression includes pharmacological treatment (agomelatine) and nonpharmacological treatments (sleep deprivation, bright light therapy, and sleep phase advance). In this paper nonpharmacological interventions are described. Although these methods are relatively safe, cheap and well-tolerated chronotherapeutics are not widely used. Nevertheless, more and more reports provide evidence for the effectiveness of these treatments in depression. Furthermore, some modifications of each technique, several integrative chronotherapeutics and combination with medication can be an alternative modality to conventional treatment. This article presents the current knowledge of principles of circadian timing and chronobiological aspects of depression. It also describes methods of chronotherapy, their implementation in everyday practice, and possible adverse effects. Next, integrative chronotherapeutics and combination with medication are presented. This paper reviews studies on effectiveness and tolerability of these interventions.