Geting out of bed on the wrong side

I'm a generally a morning person, more active and (relatively) alert it in the first half of the day. Some mornings are better than others, though, and there are days when I'm awake ridiculously early, but would prefer to dive straight back into unconsciousness, rather than spending the pre-dawn darkness fending off the raging tyrannosaurus of despair armed only with the puny toothpick of hope. After a shower, a cup of coffee and bit of activity, I generally get over it, but I was interested to read a blog post about what may be happening to the brain on mornings like that:

Suppose that, for whatever reason, you woke up during REM sleep, but your serotonin cells didn't wake up quick enough, leaving you awake, but with no serotonin (a situation which never normally occurs, remember). How would that feel?

I didn't know that the brain produces less and less serotonin as you go into REM sleep, so I'm grateful  to Neuroskeptic for the information and the theory that a disturbed sleep pattern could mean in waking a serotonin-deprived condition.

The post is speculative, but it makes it seem worth trying to beat the early morning blues by staying a up just a little bit later than normal in the evening, (like most morning people, I tend to go early to bed). Unsurprisingly, people tend to sleep better after being sightly sleep deprived and they also tend to go into REM sleep earlier in the sleep cycle. If a person was doing most of their REM sleep earlier and tired, they might get through that serotonin-deprived phase of the sleep cycle in blissful unconsciousness rather than snapping awake in the wee small hours without the benefit of an important mood-regulating neurotransmitter.

Going to bed tired and triggering a different sleep pattern might also be one of the fringe benefits of taking a bit more exercise, during the day (besides the immediate natural high and the social context of exercising). Finally, just knowing that an early morning feeling of hopeless doom may, at least in part, be a passing illusion caused by a quirk of brain chemistry is a cheering reality check.

I was also quite interested to see the lack of consensus on whether or not REM sleep is important.- the Neuroskeptic thinks it might be dispensable, whilst somebody in the comments section clearly thinks that's a completely barmy notion - nice to see a healthy battle of ideas going on there.