Prevalence of Insomnia Disorder With Age

Karl Doghramji, MD: We know that the prevalence of insomnia increases as we age, and there are a number of reasons for that. One of the major and most important reasons is that sleep seems to naturally fragment as we age. As we age, we wake up more. We sleep less during the course of the night. And the older individuals become sleepier during the course of the day and nap more. In addition, they seem to have a shortened amount of slow-wave sleep or some of the deeper stages of sleep, and an increased amount of shallow sleep or stage I sleep. There seems to be a natural deterioration in the sleep-wake cycle as we age.

The question has always been, are these changes a result of the natural process of aging? Or are these caused by medical and psychiatric and other conditions, which also increase in prevalence as we age? And the data seem to suggest that not all these changes are due to comorbid conditions. That there seems to be a natural degradation in sleep as we age. We simply cannot sleep as much as we age.

Some of the other factors that contribute to insomnia as we age include things like external influences. Noise in the setting of nursing homes, for example, strongly contributes to waking at night. The bells that are going off, the workers who are coming into the room disturbing patients as they give them medications, and so on and so forth.

The other extraneous factors that seem to be problematic are room temperature being too hot or too cold or being exposed to light at the wrong time of the day. Light exposure in the afternoon or evening hours seems to enhance insomnia or may exaggerate and delay the circadian rhythm that some older patients have. And too little light in the morning when they wake up may actually make them sleep longer in the day and fragment sleep cycles even more. Or lack of exercise. It’s been shown that older individuals, when they lie around a lot or don’t exercise that much, tend to nap more, and that steals from sleep the following night. Some of these behavioral factors are important in contributing to insomnia. But when you look at the underlying medical conditions, there seem to be quite a few as well. One of the most common complaints of older patients is nocturia, or urinary frequency during sleep, which seems to wake them up and cause insomnia as well.

In addition, many medical conditions—for example, a pulmonary condition or affective sleep apnea—increases in prevalence as we age. It’s a condition characterized by stopping breathing during sleep. Hallmark symptoms include snoring, breathing pauses, daytime somnolence. And the older individuals are more likely to have obstructive apnea. Obstructive apnea may independently contribute to cognitive decline, cardiovascular disease, hypertension, and even glucose metabolism difficulties in older patients. It’s important to diagnose that and treat that as best as possible.

Restless leg syndrome is a condition characterized by moving legs—having to get up in the middle of the night or while going to bed and walk around to make these unusual feelings dissipate. It is much more common in older individuals than younger individuals. And the treatment involves specific dopaminergic agents as well as possible iron therapy.

Consider things like circadian rhythm disturbance. As we know, the older individual is more likely to have an advancing of the sleep-wake cycle. They begin to fall asleep earlier and wake up earlier. And the treatment of that is optimal, or best done, by bright-light therapy in the evening and certain forms of glasses that block blue light in the morning. These are some medical conditions that seem to occur in older individuals and that contribute to insomnia.

Depression is a very common condition in older individuals as well. And 1 of the difficulties with depression is that, in older patients in particular, it’s difficult to diagnose because the presentation typically, or usually, does not involve the complaint of despondency, feeling down or low, gloomy, and so on and so forth. It’s often disguised by the complaint of fatigue or of being tired. Depression needs to be well diagnosed to avoid treating older individuals who are depressed inappropriately.

So there are medical conditions, psychiatric conditions, and finally medications. Many of the medications that older individuals take contribute to insomnia. Stimulants, for example, or antidepressants that have adrenergic or dopaminergic properties may contribute to insomnia, nasal decongestants, and so on and so forth. These are some of the causes of insomnia in older patients. What’s implicit in what I’m saying is that the approach to treating insomnia in the older individual really involves a systematic and careful uncovering of these multiple medical psychiatric conditions. Treating those conditions primarily are first before managing insomnia directly.

The number of comorbidities seems to be related to the severity of insomnia and the prevalence of the complaint. We find that the older individuals who have multiple comorbidities seem to have a greater preponderance of insomnia. Those who do not have multiple comorbidities have lower rates of insomnia. However, as I mentioned before, older individuals who do not have comorbidities are not freed of insomnia or the complaint of poor sleep. Because there seems to be something about the aging process, which is destructive of sleep.