When thinking about the relationship between depression and sleep, the first term that usually comes to mind is insomnia, one of the main interactions between the two. However, what’s less known is the degree to which depression can affect other aspects of sleep, and how sleep can be a useful indicator for depressive episodes. For example, researchers have found that sleep disturbances can be reliably traced up to five weeks prior to the onset of depression symptoms, and that problems with sleep linger after other symptoms (such as loss of appetite or interest in sex) have been resolved. Since dreaming can play an important role in maintaining a healthy emotional life, does depression have any negative effects on our dreams?
Changed Sleep Architecture
Dreaming occurs primarily during periods of Rapid Eye Movement (REM) sleep that occurs at roughly ninety-minute intervals throughout the night. REM sleep is often relatively short early in the night, but occurs for longer stretches of time in the last few hours of sleep.
For a depressed individual, the first REM period occurs significantly earlier than normal—typically around sixty minutes into sleep (instead of ninety) and sometimes as early as forty-five minutes in. This first REM period is also typically much longer than usual, and later amounts of REM sleep are generally less. Compared to normal, the eye movements themselves occur at irregular intervals, becoming too rare or densely packed together—which may be reflective of the different content of a depressed person’s dreams.
Changed Dream Content
For someone suffering depression, dreams seem like an infrequent occurrence: dream recall is significantly decreased in those with depression compared to those without it. When they are able to recall something, patients with depression often have dreams that are very bland and do not have the variety of characters, plot, and settings that most normal dreamers do.
Studies into the relationship between emotion and dreams have found that for healthy sleepers/dreamers, mood is generally improved by the morning, regardless of how people felt when they were going to bed. Thus, the age-old advice to “sleep on it” may actually have a practical purpose when it comes to improving one’s mood or emotional outlook.
The moods of those who are depressed, however, do not improve. Researchers who have examined the dreams of the depressed found that they fail incorporate the situations or characters in their lives that may be a source of the depression. For example, a study of people who were depressed because of going through a first-time divorce found that participants who were able to successfully incorporate their ex-spouse into their dreams, in a healthy manner, resolved their depressive symptoms (with no treatment) when a five-month follow-up was done. Participants who were unable to do so remained depressed at the end of the study. Thus, depression affects dream content in that it makes it more static, less complex and therapeutic, and more difficult to recall in general.