All my life I've had trouble with sleep. After years of fruitless research I finally asked AI and it brought up DSPD instantly. I looked into it and it's incredible just how much of it aligns with my experience.
It's not bad habits (a moral failing) or a lack of will. I love sleeping at 9pm and waking up around 4 or 5, it feels great. But I can't, no matter how hard I try. My normal sleeping time is 4am, and this is consistent for months. Even if I manage to reel in my rhythm, it will eventually drift back to 4am naturally over weeks.
Once I fall asleep I have no trouble staying asleep and sleeping a full 8 hours, and waking up naturally.
During my school years it was especially difficult for me to get up in the morning, even as a young kid. When my parents put me to bed the first thing I'd do was turn on the bedside lamp and grab a comic book because my body just wasn't ready to fall asleep. But they've never wanted to hear it and deny there is anything going on with my sleep schedule to this day. In fact, even professionals I've talked to about my sleep patterns don't know what to say aside from the usual "erm have you tried cutting off screen time?" screen time doesn't matter. I can be watching youtube videos from midnight to 4 and will suddenly start getting drowsy and just head off to bed. It's consistent.
If your sleeping schedule is "normal" (DSPD has social implications let's be honest, but too many to get into right now lol) it would be like me asking you to go to bed at 4am on a weekday instead of what I assume is your usual 10 or 11pm. Go on, just do it. Stay up until 4am. Fight the drowsiness.
It's torture and there is no reason you'd want to do that. It's like that for me, but the other way around. It's easy for me to sleep at 4am the same way it's easy for you to sleep at 11.
Basically I can't sleep until both my body and brain are ready to sleep, no matter how hard I try. I can't just go to bed at 11 and stay there until I fall asleep. I'd be tossing and turning full of energy until 4am, so I usually get back up after a while because it's just frustrating, and your back starts to itch, and you think to yourself clearly I'm not falling asleep, so why even bother staying in bed?
In fact, I may sometimes go to bed later than 4 am, but snap back to my usual time the next day. However, if I unusually go to bed at midnight or 1am one day, I won't snap back to 1am the next day but to 4am. This means that my circadian rhythm is not being pushed forward endlessly, it's staying at a certain range.
But none of this fixes the issue lol. I know about my condition now, and then what? I can't magically fix it. There's no cure for it except trying to follow a regimen all day every day.