Why you wake up at 3am worrying and what to do about it

When I wake at 3am or so, I’m prone to picking on myself. And I know I’m not the only one who does this.
A friend of mine calls 3am thoughts “barbed-wire thinking” because you can get caught in it.
The thoughts are often distressing and punitive. Strikingly, these concerns vaporise in the daylight, proving that the 3am thinking was completely irrational and unproductive.
I’m a psychology researcher with expertise in mood, sleep, and the circadian system (the internal clock regulating sleep). Here’s what the research says about what may be behind this common experience.