Insomnia: sleep patterns and anxiety level.

ALTHOUGH individuals with psychiatric difficulties (particularly depression) apparently experience a greater incidence of insomnia than individuals without psychiatric difficulties, sleep disturbances are commonly reported in both psychiatric and nonpsychiatric populations [l]. Insomniacs typically report that it requires an excessive length of time to fall asleep once they are in bed and/or that they awaken frequently during the night. There are, however, no established criteria for differentiating insomniacs from non-insomniacs, nor is data available on the sleep patterns of these two groups. It is surprising, in view of the prevalence of insomnia, that etiological factors have not been conclusively identified. Monroe [2] and Maruzzi [3] have suggested that a high level of autonomic arousal may be a concomitant, if not causal, factor in abnormal sleep patterns. Because sleep is associated with low levels of autonomic arousal, individuals who are highly aroused may experience difficulty in falling asleep or may awaken frequently at night. If an elevated level of autonomic arousal is associated with sleeping difficulties, it would be expected that insomniacs would score higher than non-insomniacs on self-report measures of autonomic arousal and anxiety, such as the Manifest Anxiety Scale [4] and on physiological measures of autonomic arousal (e.g., heart rate, skin resistance). Budzynski [5], Malmo [6], and Pinneo [7] have demonstrated that, although individual variance is substantial, electromyography (EMG) levels, which are a measure of muscle tension, are directly related to other physiological measures of autonomic arousal. It would be expected, therefore, that EMG levels of insomniacs would be greater than that of non-insomniacs. If insomnia is viewed within an operant, rather than physiological-arousal paradigm, another possible etiological factor becomes apparent. Insomnia may be associated with inadequate stimulus control of sleeping behaviors. That is, insomniacs may engage in a large number of behaviors incompatible with sleeping (e.g., eating, watching TV, reading) while in their bed and bedroom. The stimuli (i.e., bed and sleeping room) may become associated with these incompatible behaviors, /thereby decreasing the probability that the behavior of “going to sleep” will be emitted in those situations. The treatment of insomnia has historically been medically oriented (i.e., administration of tranquilizers or sedatives). Recently, however, several investigators have reported successful treatment of insomnia in a number of uncontrolled case studies using variants of systematic desensitization or relaxation training [&lo]. The use of these behavioral techniques in the treatment of insomnia is based on the premise that anxiety or heightened autonomic arousal is an etiological or maintaining factor.