Most of us have an indirect sense of our internal clock time just by knowing when we prefer to go to bed. But you can get a more objective measure of your circadian rhythm — or chronotype — and advice on what to do about it by taking this simple quiz.
Those with more serious problems than jet lag and late nights may need to make more serious changes.
Researchers have developed a limited form of sleep deprivation that is euphemistically called wake therapy. It has been shown to have sustained antidepressant benefit in patients with bipolar disorder and major depression. The idea is to get up for the day halfway through the usual sleep period, which shifts the circadian clock to an earlier time. It’s thought that this works by realigning the sleep cycle with other circadian rhythms, like changes in levels of body temperature and the stress hormone cortisol, that are also out of sync with each other in depression.
Studies show that it is possible to make wake therapy even more powerful by incorporating two additional interventions: early morning light therapy and what’s called sleep phase advance, in which the patient goes to bed about five to six hours earlier than usual and sleeps for about seven hours. This combination of treatments is called triple chronotherapy, and the typical course involves one night of complete sleep deprivation followed by three nights of phase-advanced sleep and early morning light.
In one study of 60 hospitalized patients with bipolar depression who were taking antidepressants or lithium, 70 percent of those who did not have a history of drug resistance improved rapidly with sleep deprivation and early morning light, and 57 percent remained well after nine months. Encouragingly, 44 percent of patients who had failed to respond to at least one trial of anti-depressants also improved.
In another study, investigators combined chronotherapy with psychotropic medication and found that depressed patients got better within 48 hours — much faster than antidepressants, which typically take four to six weeks to work. A second study of 75 depressed patients who were taking an antidepressant randomly assigned half to also receive chronotherapy and the other half to daily physical exercise. It found that 62 percent of patients remained well at the end of 29 weeks in the chronotherapy group compared with only 38 percent assigned to exercise.
With the possible exception of ketamine, a drug under investigation for treating depression, this therapy is the most rapid antidepressant treatment that we have. About 60 percent of depressed patients feel markedly better within hours. And — with the exception of some fatigue — there are no side effects.