Way back in 1818, a German psychiatrist reported that sleep deprivation had a weird side effect: It made some depressed people feel better.
Scientists have been studying sleep deprivation and depression ever since. A University of Pennsylvania research team has brought the data up to the present with a new meta-analysis — a study that pools data from other people's studies — of the last 40 years of work on the topic.
Their work confirmed that sleep deprivation — anything from three to four hours of sleep followed by 20 to 21 hours awake to no sleep for 36 straight hours — is indeed a powerful antidote to depression. In the 66 studies they analyzed, 45 percent to 50 percent reported feeling less depressed.
That sounds great, but there's a huge problem: For more than 80 percent of patients, the antidepressant effects are lost as soon as they get a good night's rest. Repeated exposure to sleep deprivation has had mixed results.
The study, the first meta-analysis of this topic in nearly 30 years, was published this week in the Journal of Clinical Psychiatry.
Philip Gehrman, a Penn clinical psychologist who was senior author, said the study proves that rapid treatment of depression is possible. But more research is needed to figure out why sleep deprivation works. His team is now conducting its own study. He's not hoping to use sleep deprivation as a treatment but thinks that pinpointing what it does to the brain will help doctors develop other, more sustained treatments.
Gehrman had hoped the meta-analysis would help figure out which depressed people are most likely to respond to sleep deprivation and whether the type of deprivation made a difference. "It seemed like no matter how you sliced the pie, the results were the same," he said.
Most of the studies did not have control groups, so it's hard to know how big the placebo effect was. However, Gehrman said, the response to sleep deprivation is rapid and "dramatic." While there is a strong placebo effect in other types of depression treatments, such as medication or talk therapy, the response is usually much slower.
Gehrman is attracted to the topic because it's so counterintuitive. "This whole phenomenon is the complete opposite of what anyone would expect," he said. "Why would losing sleep be in any way helpful for depression?"
People without depression feel worse when they don't get enough sleep. Those with depression often suffer from sleep problems that make depression worse. Insomnia is the most common, but some sleep too much. Treating their sleep problems often improves depression symptoms.
Experts theorize that sleep deprivation may reset the circadian clock. But it is rarely used for treatment because it wears off so fast.
"I know of about three clinics worldwide that routinely use it," Gehrman said. There are some studies showing that it can be helpful when combined with light or antidepressant medication treatment.
Gehrman's team is now using brain imaging techniques to identify which brain circuits change in response to lack of sleep. The hope is to then use neurostimulation, such as transcranial magnetic stimulation, to activate those circuits in a more fruitful way.
He's recruiting adults with moderate to severe depression who are willing to go 36 hours without sleep for science. The study requires them to spend five days in a research lab. They'll be paid $700 for participating.