Insomnia_ Normal Sleep, Age, Definitions, & Types of Insomnia
Welcome to another MedCram lecture! In the next set of lectures, we’re going to talk about insomnia, what causes it, what are the different diseases that can cause it, and how to manage it. I would say that even though I am a sleep specialist, some of the recommendations I’m going to be giving are not for everybody. So you need to make sure that you follow up with your own physician, but let’s go through insomnia.
The first thing we got to do is talk about what happens with normal aging. There are different stages of sleep. There is stage 1, what we term N1, stage 2 and stage 3, a couple of other stages as well. There is REM sleep, which I’m sure you’ve heard about.
Generally speaking, what happens over the period of a night is someone starts out awake, go down into very transient sleep phase called stage 1, and then they go down to stage 2, and eventually go down into Stage 3 where they stay until they go into REM sleep, which I’ll code here as very dark. Then they come out of that and they go right back up to the beginning of stage 1, and they repeat the same thing again.
Now as this occurs throughout the night, this REM sleep gets longer and longer until actually most of the REM sleep is towards the end of the night. These deep stages of sleep, stage 3, are usually longer towards the beginning of sleep. So something that we see here in normal sleep is that stage 3 is concentrated toward the beginning of the night, and REM sleep is concentrated more towards the end of the night.
Both of these are very restful. Stage 3 sleep is physically restful; stage 3 sleep was where growth hormone is produced. REM sleep is very mentally restorative, so both of these are very very important. Unfortunately, as we get older, we see a reduction in both of these types of sleep, an increase in this very sort of bland and two types of sleep which really is more of a light sleep. So this is what we see within normal aging.
Most of these changes occur by the age of 40 or 50 years of age, and sleep remains pretty constant from the age of 60 to 90. There is one exception and that is sleep efficiency. So what is sleep efficiency? Sleep efficiency is simply the amount of time of sleep divided by the amount of time in bed, and that steadily decreases from about 95% down to about 80% in general as one approaches 80 years of age.
So what happens when you approach middle-age? There’s a number of things that occur normally. There is increased awakenings. So you’re waking up more in the middle of the night. There are arousals. And there are more stages shifts. These are the stages I was talking about before. You also see a decrease in stage 3 sleep, and you’ll also see a decrease in REM sleep; as I mentioned before you get a decrease in sleep efficiency.
As you reach middle age, there is more of what we call a phase advancement. What do I mean by phase advancement? With phase advancement, you’re going to be getting up earlier, which means you are getting up from bed earlier and going to bed earlier. The interesting thing, however, is that despite all of these things, you are a little bit more resistant to sleep deprivation or to the effects of sleep deprivation.
What I mean by this is that let’s say as a teenager, if you missed four or five hours of sleep, it wouldn’t affect you as much as if you were older and you missed four or five hours of sleep. You’ll be able to perform a little better, which is kind of paradoxical from what you would think.
Now, in terms of disease and actual disease, insomnia goes up as we get older. No surprise there if we look at a study of 18 to 34 year-olds. Now, there’s about 14 percent incidence of insomnia from the age of 35 to 49. The incidence is about 15%, so it remains pretty stable.
However, when we get to 50 to 64 years of age, we hit about 20% incidents; here’s the key though. From sixty-five to seventy-nine years of age, that jumps up to 25%. This is a pretty astounding figure when you realize that a quarter of the population of retirement age has a problem with insomnia. And insomnia is a pretty generic term. I mean if we could use a number of different words to describe it.
Some about 19 percent of people wake up too early. Another nineteen percent would describe trouble falling asleep? 25% have daytime napping. Twenty-nine percent basically come right out and just say they’ve got insomnia.
And then if you look at both initiating and maintaining sleep, we’re looking at 43 percent of older adults. So these are people who have a mean age of 74 years of age. Of those people, these are what they’re complaining about; and 43% have problems with initiating and maintaining both.
Now, this is by no means a geriatric diagnosis. There are many young people and middle-aged people who have this problem now in terms of the different causes of insomnia. Let’s say we got rid of all of the easy causes of insomnia, for instance, drinking too much caffeine or some of these things. If we were to break it down, what would be the breakdown of insomnia in terms of causes? Well, it turns out the biggest reason for people to have insomnia, so 35 percent of people who have insomnia have some sort of psychiatric illness, and what I mean by that is depression.
So you got to know that in terms of treatment: because if you don’t treat the depression, the insomnia is not going to get better. Next on the list, about 15% have what we call psychophysiological or what we call performance anxiety.
What do I mean by that? Have you ever been in the kitchen, or in the living room, or the family room felt really tired? And then as soon as you went into the bedroom, you just could not fall asleep. This is psychophysiological. We’re going to explain about that in the upcoming lectures.
12% is alcohol or drug. Yes, these can cause insomnia. Another 12% is Restless Leg Syndrome – something that we’ll talk about, as well 10% is circadian rhythm disorder, and finally, the last nine percent is kind of a weird diagnosis. It’s actually where they think they can’t sleep, but they actually are sleeping if you test them. It’s called paradoxical.
So you can see here that this is where the bulk of your diagnosis is. This one’s going to be the most interesting. So what we’re going to do is we’ve kind of laid the groundwork of what insomnia is, where it comes from. Let’s talk about where the path of physiology meets the road in terms of causes, diagnosis, management, and treatment. Join us for the next lecture!