Two recent studies find an association between insomnia and depression in very different populations — young adults and the elderly.
Both studies confirm the persistent nature of insomnia and the increased risk of subsequent depression among individuals with insomnia.
For the elderly, in addition to being a risk factor for a depressive episode, insomnia may perpetuate the illness. This is especially true for those receiving standard care for depression in primary care settings, according to a study published in the April 1 issue of the journal SLEEP.
Likewise a study of nearly 600 young adults spanning 20 years discovered four duration-based subtypes of insomnia: one-month insomnia associated with significant distress, two-to-three-week insomnia, recurrent brief insomnia, and occasional brief insomnia.
According to the results, the annual prevalence of one-month insomnia increased gradually over time, with a cumulative prevalence rate of 20 percent and a greater than two-fold risk among women. In 40 percent of subjects, insomnia developed into more chronic forms over time. Insomnia either with or without comorbid depression was highly stable over time.
Insomnia lasting two weeks or longer predicted major depressive episodes and major depressive disorder at subsequent interviews. Seventeen to 50 percent of subjects with insomnia lasting two weeks or longer developed a major depressive episode in a later interview. “Pure” insomnia and “pure” depression were not longitudinally related to each other, whereas insomnia comorbid with depression was longitudinally related to both.
“We used to think that insomnia was most often just a symptom of depression. However, a growing body of evidence suggests that insomnia is not just a symptom of depression, but that it may actually precede depression. In other words, people who have insomnia but no depression are at increased risk for later developing depression.
This study adds to our knowledge by including a much longer follow-up period than most previous studies,” said Daniel J. Buysse, MD, of the University of Pittsburgh, lead author of the paper.
“We were also able to look separately at insomnia alone, depression alone, and combined insomnia-depression. The results show that insomnia seems to be followed by depression more consistently than the other way around. In addition, we found that insomnia tended to be a chronic problem that gets more persistent over time, whereas depression was a more intermittent problem.”
Insomnia is a classification of sleep disorders in which a person has trouble falling asleep, staying asleep or waking up too early. It is the most commonly reported sleep disorder. About 30 percent of adults have symptoms of insomnia. It is more common among elderly people and women.
While most people require seven to eight hours of sleep a night to perform optimally the next day, older adults might find this harder to obtain. Older adults must be more aware of their sleep and maintain good sleep hygiene by following these tips:
• Establishing a routine sleep schedule.
• Avoiding utilizing bed for activities other than sleep or intimacy.
• Avoiding substances that disturb your sleep, like alcohol or caffeine.
• Not napping during the day. If you must snooze, limit the time to less than one hour and no later than 3 p.m.
• Stick to rituals that help you relax each night before bed. This can include such things as a warm bath, a light snack or a few minutes of reading.
• Don’t take your worries to bed. Bedtime is a time to relax, not to hash out the stresses of the day.
• If you can’t fall asleep, leave your bedroom and engage in a quiet activity. Return to bed only when you are tired.
• Keep your bedroom dark, quiet and a little cool.
Although sleep patterns change as people age, disturbed sleep and waking up tired every day are not part of normal aging. Those who have trouble sleeping are advised to see a sleep specialist.