Circadian Rhythm and Blues
Extensive evidence suggests depression is rooted deeply in our nights.
Posted March 2, 2011
Depression is a disorder of waking life. At least, that's our common presumption.
Although insomnia is among its diagnostic criteria, depression is generally understood in terms of disrupted function and mood in waking life. Extensive evidence, however, suggests that depression is rooted deeply in our nights. In fact, insomnia and depression are so strongly linked, some experts believe they are flip sides of the same disorder - what we might think of as a depression-insomnia complex.
Trying to understand and manage depression without acknowledging its night side is like trying to understand a tree without considering its roots. Each day of depression is linked to a night of disrupted sleep and dreams. And vice versa. Disregard for the night side of this essentially circadian process obscures the critical disruption of rhythm behind our epidemic of blues.
Despite their struggle with chronic insomnia, depressed individuals are, surprisingly, not all that sleepy during the day. Although insomnia is presumed to result from insufficient sleepiness, it's actually associated with a nightly intrusion of excessive wakefulness. In fact, it's now widely accepted that insomniacs are excessively wakeful or hyperaroused, running at anincreased metabolic rate 24 hours per day. In addition to impeding sleep, hyperarousal can readily mask daytime sleepiness.
Sleep and dreams naturally slow and draw us downward into rest and restoration. Hyperarousal, on the other hand, exerts an equally powerful but opposing force, pulling us upward into excessive wakefulness. We end up caught in a persistent tension between the two - suspended in a limbic zone of depression where we are rarely fully awake, never deeply asleep, and almost always thoroughly fatigued.
Fatigue is a critical symptom of the depression-insomnia complex. Depressed individuals tend to be less sleepy by day than expected, but substantially more fatigued. Fatigue is the most common sign of depression presented in primary care, accounting for more than 10 million outpatient office visits per year in the U.S. alone. Fatigue is also the most troublesome residual symptom that persists after treatment with antidepressants.Common sense notwithstanding, fatigue is not caused by a simple lack of sleep, but by chronic excessive wakefulness.
Why are we excessively wakeful? The short answer is that we believe in speed. Speeding is, in fact, the most common infraction of the law. We equip sports cars with spoilers because things that go very fast tend to lift off and ascend. They become ungrounded. The depression-insomnia complex is usually preceded by a lengthy period of anxious and obstinate acceleration through life, sans a psychological spoiler. Why are we surprised that after years of bounding mindlessly over nature's speed bumps -- of failing to brake, slow and rest at night -- we find our circadian rhythms to be so out of alignment?
Our circadian rhythms began to degrade with the advent of industrialization when the machine emerged as our role model and artificial light as the new guiding beacon. Humans began working relentlessly like machines, overriding the impulse to rest and disentraining from natural cycles of day and night, of light and darkness. With industrialization also came the seeds of global warming and its very personal analogue, chronic inflammation. We began to overheat.
Human circadian rhythm disturbances are most evident in the disruption of our core body temperature rhythms. Normally, core body temperature is higher by day, decreases with our descent into sleep and reaches its nadir in the latter third of the night during REM or dream sleep. It's literally true that sleep is cool and dreaming is the coolest part of sleep. Depressed individuals, however, have blunted temperature rhythm variability and interestingly, an increase in their average core body temperature. They run hot. In fact, some depressed individuals actually run a fever between 1 ½ to 2 degrees above normal - especially at night. Also known as hyperthermia, increased core body temperature has been linked to both chronic inflammation and the fatigue that usually accompanies depression. In all likelihood, fatigue functions to discourage activity so that we might cool down.
Remembering that insomnia is not simply about sleep loss, but also about disrupted REM sleep or dream loss sheds more light on the depression-insomnia complex. The most common pattern of insomnia associated with depression actually does more damage to REM/dreaming than it does to sleep. REM/dream loss is the most critical overlooked socio-cultural force in the etiology of depression. Most of us are at least as dream deprived as we are sleep deprived because we live in a world that dismisses the value of dreaming. This posture is clearly evident in our blatant disregard for the REM suppressant effects of many commonly used medications, including many sleeping pills, most tranquilizers and virtually all antidepressants.
Many of my patients say outright that they don't want to dream. Why should they? They read somewhere that dreamless sleep is best. Furthermore, they find that most of their dreams are bad, if not nightmarish. About two-thirds of the emotional content of our dreams is, in fact, bad. Looking at it more broadly, however, we might make the same argument for waking life. There's immense struggle and suffering on this planet. But, just as bad feelings can be part of a good life, bad dreams can be part of a good dream life.
Growing evidence suggests that healthy dreaming helps us process and heal emotions. REM/dreams in the first part of the night appear to process and diffuse residual negative emotion from the waking day. Dreams later in the night then integrate this material into one's sense of self. Dreaming is a kind of psychological yoga that expands constricted consciousness. And, as interesting and helpful as dream interpretation might be, simply knowing that dreaming is meaningful is more important that knowing the meaning of any particular dream.
When we lose sleep at night, our sleep drive rebounds into the following day. We get sleepy. When we lose nightly REM sleep or dreams, might they also rebound into our waking day? Do we get "dreamy?" Selective suppression of REM/dreaming in humans does result in a REM/dream rebound that further disrupts our normal sleep and dream rhythm. When REM is extensively suppressed, we can experience waves of dream-associated mentation actually breaking through to waking consciousness. This can leave us somewhat dreamy, but not in any romantic sense.
The dream clearly has its place in the framework of nightly REM sleep or even through waking waves of creative inspiration. Naturally diffused, non-linear and expansive dream consciousness, however, is not all that conducive to balancing one's checkbook or numerous other waking world tasks that require our focus and linear attention.
Breakthrough dream mentation and heat-driven fatigue combine to generate a kind of waking fever dream, the very brand of constricted consciousness we call depression. Depression wants to expand; it wants us to withdraw from excessive waking activity to rest and dream. The symptoms of the depression-insomnia complex then might be viewed as a functional, psychological fever -- an endogenous healing response that attempts to reduce the heat of excessive waking by slowing us down and opening us up.
Newer antidepressants, the majority of which are REM suppressant stimulants, essentially mask symptoms of depression by suppressing dreaming and encouraging excessive wakefulness. In contrast, depressed individuals encouraged to surrender to fatigue and truly rest, can once again open their hearts to the healing process of dreaming.
Dreaming is a natural, neurological art. The dream gathers dark, splintered, disparate emotions and experiences. It collects unresolved pain, confusion, grief and fear. And it rearranges all this bad stuff into a good form. It creates a collage. It produces pithy vignettes, writes good short stories or, on occasion, great epic tales. It creatively transforms our dark stuff into something cohesive, presentable and imaginative -- even if more mysterious. Even if we cannot discern the dreams exact meaning, we are almost always left with a clear intuitive sense that the dream is, indeed, meaningful.
Dreaming is antidepressive. It restores something expansive and rhythmic to the flow of consciousness.
© 2011 Rubin Naiman, PhD
Part II of this article, which discusses specific recommendations for the depression-insomnia complex, will appear in next month's post.