Since there are many different kinds of sleep disturbance, the causal factors are extremely varied.
Many psychological, pharmaceutical and environmental factors can bring about disturbed sleep, and disturbed sleep WILL exacerbate any psychological problem and many physiological problems.
In fact, often the very medication designed to relieve undesirable symptoms can over the long term produce exactly the opposite result. Even to the point of strengthening those same symptoms and adding new ones when the medications begin to affect a persons sleep.
It is very common as people age, that the amount of sleep they get decreases - especially slow wave and REM sleep. This has led many to assume that older people need less sleep. Some even consider it true that older people need less REM sleep especially. But this is not at all the case!
The need for sleep does NOT change from early adulthood to later adulthood. You need sleep in the same quality and quality as an adult human no matter how old you get.
The fact that many elderly people sleep less, waking earlier and more often means they dream less and get less slow wave sleep. This builds up a sleep debt which leads to many other undesirable conditions. We usually consider these "just part of aging."
But those same conditions may have been avoided had they gotten a good night's sleep every night. Dreams and dreaming are essential for the long term healthy functioning of the nervous system. Slow wave sleep the main rejuvenating process that allows all the other organs of the body to stay healthy. As these stages of sleep are reduced while people progress through adulthood the maintenance processes for general health as well as the opportunities for self healing are also reduced.
Source: Hobson. Sleep and Dreaming. In: Fundamental Neuroscience. 1999. Roffwarg et al. Science. 1996;152:604. Cited in The Weeks Clinic for Corrective Medicine and Psychiatry Sleep Lecture
Yet, even though this is what tends to happen to human beings as they age it need not be. With the right approach to sleep and rejuvenation, the predetermined "normals" can change.
Yes, unless you are not normal, your REM and Slow Wave Sleep will reduce as you age. But this happens because of other factors, independent of age. For example, you may have increasing, underlying discomfort. This might be due due to inflammation or carrying too much weight. Or you may experience discomfort from organ damage, especially skeletal system damage. Or from medications, as mentioned above. Alternatively, you may experience an underlying increase in cognitive arousal. This could be because you are suffering chronic low-level stress, worry or anxiety. As you get older you get more mind-content to worry over and more opportunity to get fixed in the bad habits of worry. Or you may simply but increasingly have an unnecessarily busy mind. Again, as you get older, your mind's tendency to problem-solve, to turn events over-and-over can become a habit which occupies more and more of your consciousness.
However, we should bear one simple fact in mind. These are not conditions fixed in stone.
In fact, they can be stopped, turned around and sent in the opposite direction with the aid of a program that deals with the sleep system as a whole.
Clinical Hypnosis, with it's voluntary-involuntary mixing of consciousness resources is tailor made for systematically building such a holistic program.
And in fact, we have.