The surprise

One of the most counter-intuitive findings in psychiatry is that for some people who are clinically depressed, depriving them of sleep for a night can provide immediate relief. While drugs or psychotherapy can take weeks to take effect, sleep deprivation provides a break in the cycle of depression almost immediately. Unfortunately, while the relief can be profound, it is also temporary. Most people relapse into depression as soon as their next sleep happens.

The investigation

Dr. Philip Gehrman, associate professor of psychiatry at University of Pennsylvania medical school and his colleagues have done a systematic review to try to understand how often this works and for whom. What they've found is that about 50 per cent of paitients with both bipolar and unipolar depression can respond to this — and different regimes of sleep deprivation work as well, which means this is a kind of 'broad spectrum' approach that could be used more widely.

The future

Dr. Gehrman and his associates now want to delve deeper into the phenomenon to see if they can understand the mechanism for how sleep deprivation relieves depression. They hope that if they can understand it better, they can perhaps find ways to produce longer-lasting effects in more patients.