As we have been discussing, chronic insomnia is insomnia in the absence of other medical, neurological, or psychiatric causes. Two of the most common types of this disorder are idiopathic insomnia and psychophysiologic insomnia. I will also briefly touch on another interesting and poorly understood form of insomnia.
Idiopathic insomnia (aka primary or childhood-onset insomnia) is a lifelong problem that some people have initiating and maintaining sleep, which can cause severe impairment in daytime functioning, mood, and possibly other health-related problems (see previous blog on** "** How Sleep Deprivation Affects Your Health"). Researchers have suggested that this form of insomnia, which often can be debilitating, may be due to an imbalance in certain chemicals that keep us aroused and help us sleep. Either the transmitters that normally keep us awake are hyperactive in these patients, or the mechanisms that allow us to fall asleep are underactive.
Psychophysiologic insomnia (PPI) is also called learned or conditioned insomnia. It is estimated that about 15% of patients that come to sleep clinics have this disorder, but I think it occurs more often than that in my sleep clinic. The patient with PPI "learns" sleep preventing associations and becomes so focused on the idea of sleep, that when sleep does not come they become agitated, frustrated and stressed, which is certainly not compatible with sleeping.
In essence, the bedroom becomes a dreaded place, because of the patient's frustration with attempts to fall asleep, causing an actual "physiologic" response by the body, such as muscle tension, racing thoughts, sweating, anxiety, etc. Occasionally, a stressful life event can start this disruptive process, but then it takes on a life of its own. Also, due to the association of one's own bedroom with sleep problems, people with PPI may sleep better outside of their home, such as at a hotel or friend's house.
What is fascinating about this form of insomnia is that it feeds on itself - the harder it is for the patient to sleep, the more the patient focuses on the inability to sleep, and the harder it becomes to sleep Obviously, this can present a very frustrating and difficult cycle, which may be helped by some "re-educating" the sufferer on how to fall asleep (more on this when I talk about treatment).
A third type of insomnia is called paradoxical insomnia. In this category we have patients who appear to sleep well by our current understanding and ways of measuring sleep during a sleep study. The problem is that the patients insist they sleep very little, or not at all. This used to be called sleep-state misperception because by traditional measurements, these patients were sleeping well. This term was felt not to fully appreciate the complaints of the patient because even though we can measure "sleep" by checking the patient's brain waves, we can not measure how deeply the person is sleeping.