Sleep Disorders

Sleep Disorders

Sleep disorders can be divided into four major categories: 1) insomnias, disorders associated with complaints of insuf-ficient, disturbed, or nonrestorative sleep; 2) hypersomnias, disorders of excessive sleepiness; 3) disturbances of the cir-cadian sleep–wake cycle; and 4) parasomnias, abnormal be-haviors or abnormal physiological events in sleep (American Psychiatric Association, 1994). By definition, the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) limits itself to chronic disorders (at least 1 month in duration). On the other hand, the International Classifica-tion of Sleep Disorders includes sleep disorders of short-term and intermediate duration, which in fact are more common than chronic disorders (Diagnostic Classification Steering Committee Therapy MJC, 1990).