It simply has to do with down-regulated GABA receptors. GABA receptors are your body's brake pedal or what makes you calm and relaxed. Glutamate receptors are your body's gas pedal or what makes you active and alert, even fight or flight. Normally both are in balance so one doesn't overtake the other. When they are in balance you sleep normally and you don't have symptoms. But when Benzos temporarily take GABA offline, Glutamate rules the day and night, so you are wired all the time and can't sleep even though you might feel tired. Until GABA receptors heal and/or regrow, you're in for a period of insomnia that Ashton says typically lasts 6-12 months for most. Non 24 isn't necessarily insomnia, just a different circadian rhythm that isn't in line with a night/day "normal" sleep routine.
If you are sleeping but on a different schedule that you'd like, sometimes melatonin can reset your rhythm?
Sleep Drive isn't the only system for sleep. You also have your Circadian Rhythm. Just like most people tend to get hungry around breakfast, lunch and dinner time, most people start to get sleepy around 10:00 - 11:00 pm at night. Some earlier, some later, but regardless this is your Rhythm.
When your Sleep Drive is high and your Rhythm is locked, sleep occurs fairly easy.
However, if either one of these (Drive or Rhythm) is off, you can have a sleep disorder.
You can have a high sleep drive but an "out of sync" Rhythm or vice versa. Then sleep is hard to come by.
You can get in bed and feel exhausted (high sleep drive) but your Rhythm is off so it's hard to fall asleep!
Benzos temporarily remove your Sleep Drive, hence the insomnia. But if you still have Sleep Drive but at a different part of the day or night than you'd like, then it may not be Benzo induced?
Non 24 Circadian Rhythm occurs almost exclusively in blind people. If you're not blind and you have Non-24, it might be because there are problems in the way your brain is getting light from your eyes.
Non-24-hour sleep-wake disorder in blind people is commonly treated with melatonin supplements or the FDA-approved melatonin receptor agonist, tasimelteon. Taken at a specified hour before the desired bedtime, these substances help prepare the body for sleep at the same time every night.
Good luck....