“The overall message that poor quality and insufficient sleep lead to poor mood, which, in turn, worsens sleep was not surprising,” said lead author David A. Kalmbach of the University of Michigan Medical School in Ann Arbor.
More noteworthy, he added, was that these relationships were evident in healthy, young women, not just insomniacs or depressed people.
The researchers studied 171 female college students for two weeks, beginning with an in-person questionnaire assessment of anxiety and depression levels and continuing with daily self-reported measures of mood and anxiety. The women also reported their total sleep time, time to fall asleep, and ratings of sleep quality each night.
On average, the women slept for seven hours and 22 minutes each night, taking 21 minutes to fall asleep. Overall, they rated their sleep quality “fairly good.”
At the start of the study, a third of the women scored in the “at risk” range for depression and 17 percent had clinically significant anxiety.
Women who averaged less sleep per night over the two-week period tended to report greater “anhedonic” depression symptoms, or the inability to enjoy pleasurable things. But they also tended to report more of these symptoms the day after a night of particularly long sleep, as reported in Sleep Medicine.
One night of sleep deprivation may improve mood the following day. But unfortunately, “therapeutic effects of a night of sleep deprivation are typically short-lasting, and because chronic sleep deprivation increases depression-risk, the therapeutic benefit of sleep deprivation on depression is modest at best,” Kalmbach said.
When women felt greater general distress, they took longer to fall asleep and slept more poorly. Higher levels of depression symptoms tended to come before a night of longer time to fall asleep, shorter total sleep time and poorer sleep quality.
Depending on the cause of the sleep problems, treatment for depression and anxiety can improve sleep quality, Kalmbach told Reuters Health by email.
“Unfortunately,” he added, “for depressed and/or anxious individuals who have successfully gone through psychiatric treatment and no longer have a diagnosis, what we see is that sleep problems often linger, because they do not fully resolve.”
Treatments for sleep apnea and insomnia have helped ease depression symptoms, but treatments for sleep disorders are not a cure for depression or anxiety, he said.
“Sleep and mood are similarly related in men and older women such that sleep problems worsen mood and vice versa, and that the relationship between depression and poor sleep is stronger than the relationship between anxiety and sleep,” he said.
“People who are concerned with their sleep or believe they may have a sleep disorder should seek the help of a sleep physician or sleep psychologist to discuss treatment options,” Kalmbach said. “Early attention toward sleep problems is likely to lessen risk for depression or anxiety, which can develop over time when sleep problems are not addressed.”