Not all insomniacs are zombies, (barely) living on just a few hours of sleep every night. The clinical definition is far broader than that.
The criteria for a diagnosis of primary insomnia include a difficulty falling asleep, remaining asleep, or receiving restorative sleep for a period no less than one month. This disturbance in sleep must cause significant distress or impairment in social, occupational, or other important functions and does not appear exclusively during the course of another mental or medical disorder or during the use of alcohol, medication, or other substances.
Consistent difficulty in falling or staying asleep that causes problems during the day is all it takes to be an insomniac. That can mean instead of getting, say, 7 hours of sleep each night, one gets only 5 or 6 a handful of nights a week. That can happen, for example, if you devote 7 hours to sleep but it takes you 30 minute to fall asleep and then you wake up in the night and can’t return to sleep for another 30 minutes or more. You’re still getting a lot of sleep, just not quite what you need. The key is that it has to be problematic for daytime function or the cause of distress. There are tons of people who only sleep 5 or 6 (or fewer) hours many nights of every week. But if they’re not upset by it and they function fine, they’re not insomniacs.
On the flip side, many insomniacs actually function very well most days and have nights of decent sleep. I am (was) one of them. It’s not like I was up at all hours every night, which is what I think many people assume insomnia must be. I bet a lot more people are insomniacs than are willing to admit. I also bet a lot of people could sleep better with a little help. Next week, I’ll report on my recovery.