We know that intermittent fasting can have quite a salutary effect on both fat loss and aging. This can be for a number of reasons, but perhaps the main one is that it stresses the organism. It’s a form of hormesis. Could this principle apply to other modalities of life besides diet and exercise, such as, for instance, to sleep? Yes.
It’s been known for some time that missing a night’s sleep can provide instant relief from depression. This works, believe it or not, in the majority, perhaps 75%, of those suffering from major depressive disorder, with efficacy on a par or better than antidepressant drugs. There are several important caveats, however, one being that sleep afterwards, even a nap, often brings a relapse of symptoms. One might not think sleep deprivation would be of much use if it’s the case that sleeping again often causes relapse, but one would be wrong.
Back when I used to work the occasional graveyard shift, I noticed a strange uplift in mood after the first night’s shift. This would usually dissipate after further shifts, since cumulative lack of sleep began to take hold. But it turns out that sleep deprivation does in fact work in people who are not even depressed, and can cause people with a tendency to mania to become hypomanic or manic.
The origins of the knowledge of the relation between sleep deprivation and depression are usually thought to go back a few decades, but it’s been discovered that the first ever professor of psychiatry, Johann Christian August Heinroth, wrote about the link as early as 1818. (Heinroth switched from the study of theology to become a doctor “specializing in illnesses that he judged to be related to the soul. This meant that he could be a doctor and also pursue his pastoral passion. Heinroth’s entire concept of mental health and illness was determined by his Christian faith and could be understood as a theopsychiatric symbiosis.”) It seems that he discovered this using only his acute powers of observation.
This topic has been studied extensively, yet few people are aware of it. One reason is that there are so few financial incentives here: no drugs to sell, no expensive doctor visits. A number of theories exist as to why it works, and while some facts have been established, it appears that there’s no consensus on the mechanism of action. Sleep deprivation induces an increase in levels of brain-derived neurotrophic factor (BDNF), and this correlates with efficacy of the treatment. Other mechanisms are postulated: “Sleep deprivation rapidly upregulates several plasticity-related genes, effects that are noradrenergically mediated; these are the very same genes that are upregulated by chronic antidepressants.” Some of the genes that are upregulated are those that concern circadian rhythms. Sleep deprivation also “amplifies reactivity throughout human mesolimbic reward brain networks in response to pleasure-evoking stimuli….These neural changes were accompanied by a biased increase in the number of emotional stimuli judged as pleasant in the sleep-deprived group, the extent of which exclusively correlated with activity in mesolimbic regions.”
There have been some studies in ways to get around the relapsing effect of further sleep. Advancing the sleep phase caused over 60% of those who responded initially to sleep deprivation to retain improved mood. Sleep phase advancement means going to bed later; in this case, the patients went to bed at 5:00 P.M. after one night of total sleep deprivation, and then an hour later each day until they were sleeping from 11:00 P.M. to 6:00 A.M. Another method that has been tried with success is to combine sleep deprivation with light therapy. This usually consists of exposure to bright light (10,000 lux) for an hour in the early morning. “Patients treated with wake therapy in combination with bright light therapy and sleep time stabilization had an augmented and sustained antidepressant response and remission compared to patients treated with exercise, who also had a clinically relevant antidepressant response.” (Bright light therapy alone can be as efficacious as antidepressant drugs. Here’s another therapy that there’s no money in, so most haven’t heard of it.)
Partial sleep deprivation can be as effective as total, and in addition it is easier to do and less stressful. In partial sleep deprivation, the patient wakes up after 4 hours of sleep, at perhaps 2:00 A.M. “Current opinion is that partial sleep deprivation (PSD) in the second half of the night is equally effective as TSD [total sleep deprivation]. There are, however, indications that TSD is superior.” (From Therapeutic use of sleep deprivation in depression.)
In sleep deprivation, the “reported response rates to the treatment are similar to those observed with antidepressant drugs”. Besides this, there are few side effects, and physical illness appears to be the only contraindication. By contrast, antidepressant drugs can cause sexual dysfunction, among other things, not even to mention the black-box suicide warnings now put on the labels of some antidepressant drugs.
So, here we have a no-cost, simple, and effective treatment for depression, and which can even more effectively be combined with bright light therapy and exercise. The patient merely skips one night’s sleep, or in the case of partial sleep deprivation, sleeps only 4 hours, or the first half of the night. After that one’s night’s sleep loss, going to bed later on successive nights may prolong the antidepressant effect. Note that you might come across this therapy labeled as “wake therapy”, which sounds kinder and gentler.
A few unanswered questions I have include whether patients drank coffee when they awoke – I presume they did, and there’s nothing I know that says that this would mitigate any effects, in fact I think it would strengthen them; and whether sleeping less overall, say 7 hours regularly instead of 8, would generally improve mood. A good night’s sleep is extremely important for health, and insomnia is considered a symptom of depression, but maybe too much sleep is no longer a good thing.