Delayed sleep phase disorder means that if you go to sleep when you're sleepy and get up when you're done sleeping then you're going to bed and getting up at least 2 hours later than neurotypical people with "normal" circadian rhythm.
It's literally defined as a disorder because if you sleep the way your body and brain wants to sleep then that will be in conflict with the opening hours of things like schools, and banks, and your job.
If it wasn't for those things, sleeping when you're sleepy and getting up when you're done sleeping wouldn't cause any issue.
In fact, by forcing your body out of it's natural rhythm, even when doing all the treatment things of light control and melatonin supplementation, you are liable to develop symptoms of sleep deprivation.
These symptoms won't be severe to begin with but will get progressively worse over time.
These symptoms are things like:
- reduced attention span
- slowed reaction times
- difficulty focusing
- memory issues
- headaches
- light sensitivity
- difficulty with thermoregulation of body (constantly feeling cold/hot and body temperature fluctuations)
- reduced awareness of surroundings
- weakened immune symptoms
etc, etc, etc...
If enough sleep deprivation builds up a person may even develop full blown psychosis.
If any of these symptoms already exist for you (f.ex. if you have chronic pain issues, ADHD, or any number of neurodivergencies) the slowly building sleep deprivation of forcing yourself to get up 2+ hours earlier than your body and brain naturally wakes up at will make those symptoms much worse.
If you have ADHD, you're Extremely Likely to have delayed sleep phase disorder.
And it's only a "disorder" because our social environment won't let us rest when we need it resulting in literally making us sick.
Why do you think we burn out so hard?