A night without sleep can sometimes provide temporary relief for depressives. Researchers at the University of Groningen have found that anti-depression treatments such as sleep deprivation have a more favourable effect the greater the variation in the daily mood pattern of the patient. The study was financed by the NWO's Council for Medical and Health Research. Its aim was to test the theory that depression is the result of a disturbance in the biological clock.
Depressives often display regular changes in mood over the course of the day, with some being sombre in the morning and more cheerful in the evening, for example. The Dutch researchers evaluated the mood of 81 patients twice a day by having them fill in an internationally accepted self-assessment questionnaire for depression. On average, the patients suffered from major mood swings once every four days, while in some of them this even took place on four out of every five days.
In the patients with the greatest daily mood changes, the researchers then altered the running of the biological clock with respect to their sleep-wake rhythm by exposing them to light during the morning and evening. The body reacts immediately to such interventions and adjusts its biological clock. Nevertheless, these interventions did not produce any improvement in the patients' mood, nor did they produce depressed mood in members of a healthy control group. This would appear to show that depression is probably not the result of disturbances in the biological clock. The scientists also discovered a correlation between the extent to which daily mood swings change from day to day and the effect of anti-depression treatments.
The various treatments lasted six weeks and consisted of anti-depressive medication, sleep deprivation and psychotherapy. They turned out to be more effective the more the mood pattern changed from day to day. The actual nature of the treatment made no difference. The researchers therefore assume that further research into ways of increasing the sensitivity of patients to stimuli will be more effective than research devoted to finding the best therapy for a specific patient.
Further information:
Marijke Gordijn (University of Groningen)
T +31 50 363 7658
F +31 50 363 2148
E-mail: m.c.m.gordijn@biol.rug.nl