Why does depression ease in the evening

Awake therapy for a good mood

REM sleep is characteristically changed in depressed patients: the time from falling asleep to the occurrence of the first REM phase is shortened, the REM density is increased and the first REM phase is noticeably long. "REM sleep probably has a depressive effect," says Professor Dr. Thomas Pollmächer, Director of the Center for Mental Health at the Ingolstadt Clinic, opposite the PZ. For example, point out that most antidepressants suppress REM sleep. Partial sleep deprivation, in which the patient remains awake during the REM sleep-heavy second half of the night, also has an antidepressant effect, as does selective withdrawal of REM sleep. The depressive effect of this sleep phase is probably related to the fact that mood-lowering neurotransmitters such as acetylcholine are increasingly released in this phase, while the concentration of the messenger substances characteristic of positive moods such as serotonin, norepinephrine and dopamine are particularly low, explains Pollmächer.

A more recent study from January 2013 suggests that another molecule could play a role that is involved in regulating the sleep-wake cycle: adenosine. Astrocytes produce the messenger substance in the waking phase. This is how sleep pressure builds up: the more adenosine there is, the more tired we become. The protein is probably also responsible for the antidepressant effect of sleep deprivation, as researchers led by Dustin Hines from Tufts University Boston report in the journal "Translational Psychiatry" (doi: 10.1038 / tp.2012.136).

They had given mice with depressive symptoms three doses of an adenosine agonist, mimicking sleep deprivation. Although the animals continued to sleep normally, their mood improved rapidly. This effect lasted for about 48 hours. The researchers hope that adenosine agonists could become a potential therapy option for depression.

Hardly any side effects

Sleep deprivation is exhausting, but safe. "The patients are naturally tired," reports Pollmächer. "But side effects of the therapy are not known." Theoretically, it cannot be ruled out that the increase in drive through sleep deprivation also increases the risk of suicide, as is known from therapy with antidepressants. In order to minimize this risk, the watch therapy takes place under supervision. Epilepsy patients should be excluded because sleep deprivation has an impact on them, says the doctor.

"Sleep deprivation is a well-known, established procedure, but not an effective healing method," says Pollmächer. Because the patient's mood improves only briefly, sleep deprivation mainly serves as a support for other therapies. Above all, it is used to show patients that they can have positive feelings again, and to awaken their spirits, explains Pollmächer. To see that they can still be happy is an important experience for many patients. /

*) Name changed by the editor