Orexin in depression: Evidence from basic and clinical research

Orexin – a neuropeptide – is extensively distributed in the central nervous system and is involved in the regulation of diverse physiological functions and behaviors. Orexin is strongly associated with the onset and development of depression. The most important function of orexin is to interact with the transport system, mediating arousal, and energy homeostasis. Hypothalamic-ventral tegmental and hypothalamic-ventral thalamic pathways provide clues for understanding the function of orexin and related disorders, such as sleep disorders, eating disorders, and substance abuse. This article summarizes the basic and clinical studies on the role of the orexin system in regulating and treating depression, including the relationship between the expression level of orexin in specific brain areas and diseases, relationship between adolescent depression and orexin, orexin receptor antagonists as a treatment for depression, and narcolepsy, which is closely associated with depression. Research progress on the role of orexin in depression and recent relevant studies are summarized, providing novel directions for developing depression treatment strategies.