WASHINGTON — For some years now scientists have known that restricting the sleep of very depressed people acted, as Dr. David Sack puts it, "like a sort of window into wonderland," lifting the depression as if by magic.
For a while, the phenomenon was little more than a curiosity--of genuine, albeit academic, interest, but of little practical use because sleep slammed the window shut. Once the patient went back to sleep, the depression returned.
Now, however, some researchers at the National Institute of Mental Health are finding that by manipulating sleep cycles, they can apparently bring genuine relief to some depressed patients. This relief appears to be as effective and lasting as that produced by anti-depressant drugs--but with no side effects.
Sack, who is a staff psychiatrist at the Clinical Psychobiology Branch of NIMH, describes one 43-year-old teacher who "was so disabled by her depression she couldn't enjoy anything. She couldn't go out. She was hopeless, had suicidal thoughts, no energy. She felt worse, much worse in the morning. She had a long history of depressions and she'd had just about every treatment known to man--tricyclic anti-depressants, MAO inhibitors, lithium. She had an excellent therapist and had been in psychotherapy for many years, but she just didn't respond."
At the NIMH lab, she was treated only by depriving her of a few hours of sleep each night for three nights. "After three days," says Sack, "her mood completely improved and stayed improved. We followed her for the next six months, and although she did relapse after that time, she improved again in response to the partial sleep deprivation.
"In her case we felt we had a treatment that we knew was going to be effective in her depression and a treatment we could re-administer when she got depressed again.
"We don't know that everyone is going to respond this quickly -- in fact, we don't think they will. But the point is that there was a dramatic improvement over a short period of time and the improvement was sustained.
"It wasn't just a flash in the pan."
Sack and his colleagues--Drs. Steven James, Norman Rosenthal, Thomas Wehr and Wallace Mendelson--are starting a new study, hoping to fine-tune the use of partial sleep deprivation to bring this promising non-drug therapy to millions of people for whom life is a perennial downer, a gloom broken in some cases only by episodes of joyless manic highs.
The work by the NIMH team is based on a series of studies involving the relationship between sleep and mood, as well as on the ever-growing knowledge about how the brain works and influences the rest of the body.
Scientists really do not know exactly why humans sleep. "One should say," Sack says, "that it is not entirely understood what the goal or purpose of sleep is, that a major question in the whole sleep-research field is what is the function of sleep.
"This intuitive notion that sleep is what makes you feel energetic in the morning is probably not true. I think it is important to know that even if you didn't go to sleep, you would feel tired when you went to bed and you would feel less tired when you got up in the morning. The cycle in fatigue and wakefulness is not dependent on actually attaining sleep. Sleepiness and sleep are two different processes."
But whatever goes on during sleep, the sleep disturbances appear to be an integral part of a number of psychiatric disorders, especially depressions, whether they are unipolar (depression alone) or bipolar (depression alternating in cycles with manic highs). Indeed, Sack hypothesizes that it is just as correct to say that "depression is a disorder of sleep and activity as it is to say that depression is a disorder of mood," as it is usually characterized. Depressed patients often sleep intermittently or too much, waken in the night unable to fall back to sleep or are unable to get to sleep.
One study published in the late 1970s hypothesized that it was the period of sleep called REM, or rapid eye movement, that is disordered in depressed persons. Dr. Gerald W. Vogel at Emery University hooked up a group of depressed patients to equipment in a sleep laboratory and woke them every time they went into REM sleep--as many as 30 times a night. The depressed patients gradually improved, but again, this was a therapy that was impractical even in a hospital setting, requiring, for instance, one technician per patient throughout the night. The scientists are pursuing research leads suggesting that sleep-wake cycles are linked to the regulation of certain hormones and neurotransmitters (brain chemicals) that can affect moods. Also there is evidence that sleep may help synchronize the body's various biological rhythms, those that regulate body temperature and others that govern the production or suppression of certain hormones.