Aging, circadian rhythms and depressive disorders: a review

Area of Science:

• Gerontology
• Psychiatry
• Sleep Medicine

Background:

• Aging is associated with behavioral changes, including circadian rhythm disruption and depressive disorders.
• These changes are increasingly recognized as overlapping and interconnected in the elderly population.

Purpose of the Study:

• To review the current understanding of circadian rhythm changes and depressive disorders in aging.
• To examine epidemiology, pathophysiology, clinical aspects, and treatment options for these conditions in older adults.

Main Methods:

• A non-systematic review of English-language PubMed articles published between 1995 and December 2012.
• Keywords included "circadian rhythms", "mood disorders", "depression", "age", "aging", "elderly", and "sleep".

Main Results:

• Sleep disorders, particularly insomnia, and depression are highly co-prevalent and mutually influence each other in the elderly.
• Age-related circadian disruption, especially involving the melatonin system, is well-researched, but direct links to mood disorders require further clarification.
• Shared genetic changes and proposed models suggest a bidirectional relationship between circadian disruption and depression.

Conclusions:

• Despite complexities from co-morbidities (e.g., dementia, stroke), treatments for elderly patients often target the bidirectional link between sleep and mood.
• Therapeutic options include Cognitive Behavioral Therapy, Chronotherapy, light therapy, melatonin agonists, antidepressants, and sedatives.