Psychology Today: The majority of individuals with depression suffer from insomnia, and individuals with insomnia are more likely to develop depression than those without insomnia.
For example, insomnia is associated with a twofold greater risk of developing depression in individuals over 60 years of age.
Insomnia is very common in the elderly. It is associated with the development of depression in those without a prior history of depression and with a reoccurrence of depression in those who have had prior depressive episodes.
Although many elderly individuals with depression respond partially to medications and/or psychotherapy, only about a third experience complete remission of symptoms. Preventing depression would likely be a more effective approach at alleviating suffering and disability than treating symptoms once they occur. In a paper published recently in JAMA Psychiatry, Michael Irwin and colleagues report the results of a study examining the effect of treating insomnia on subsequent development of major depression in individuals 60 years and older.