Different Kinds of Sleep Problems
Delayed sleep: inability to fall asleep within 20 minutes of going to bed.
Early waking Advanced-phase sleep: inability to sleep past X time despite getting a less than healthy amount of sleep.
Apnea: repeated wakings during the night because breathing has stopped.
Insomnia: inability to maintain sleep during the night. Not the same as light sleep. (Note: Delayed & advanced sleep phase are generally lumped under insomnia; personally, it’s possible they’re actually circadian rhythm disorders, which is also its own category and can be treated with light therapy and a very strict sleeping regimen.)
For real fun, sometimes these travel in packs!