thesadcycle

Dr. Pawluk came to talk to us about sleep medicine today, and managed to condense his lecture into about 50 minutes to our relief. He's obviously in the right field because the way he talks just makes you want to curl up inside his vocal cords and take a long nap; it's so soothing and slow and soft... a..nd...zzZz.z....Zz.z.....

Anyways, people with major depressive disorder (MDD) tend to have low quality sleeps, despite the fact that they display hypersolemnence (and just general avolition really). Normal people tend to have this sleep architecture where they'll experience a some slow wave sleep in the early stages, then flip to lots of REM earlier in the morning. People with MDD generally have lots of REM, replacing the early slow wave sleep they should be getting to feel well rested, and generally have little to no slow wave sleep at all.

One could think this is epiphenomenal, but a very very interesting hypothesis presented is that the insomnia is therapeutic. What? There was an interesting note that someone published a long time ago that found that total, partial, or just REM sleep deprivation (waking the patient up when they hit REM) led to extremely positive antidepressant effects, with up to a 60% success rate! Of course, this makes for a shitty long term therapy (imagine depriving someone of sleep every day) and isn't long lasting, but it prompted the idea that increased REM pressure in your sleep cycle is not a good thing.

Adrien (2002) thus proposed that the body attempts to create a therapeutic, protective state to rectify affective dysfunctions by mimicking sleep deprivation. This is done by creating insomnia, the mechanism of which lies in increased REM pressure, as seen on the EEGs of MDD patients. Unfortunately, increased REM also means poor sleep, but I guess the body decided to make the tradeoff between sleep hygiene and affective function.

Fascinating, I know. It goes to show that things don't necessarily share a causal relationship, and that there may be a more complex relation between two entities. It's always important to keep the most basic elements of the scientific method in mind, no matter the nature of your research.