There is also a burden to the Nation in terms of billions of dollars lost as a consequence of functional impairment. It is hoped that this Consensus Statement, which is based on rigorous examination of current knowledge and practice and makes recommendations for research and application, will help reduce suffering and improve the functional capacity of affected individuals. Pain Pain is defined by the International Association for the Study of Pain as an unpleasant sensory experience associated with actual or potential tissue damage or described in terms of such damage. It is a complex, subjective, perceptual phenomenon with a number of contributing factors that are uniquely experienced by each individual. Pain is typically classified as acute, cancer- related, and chronic nonmalignant.
Acute pain is associated with a noxious event.
Its severity is generally proportional to the degree of tissue injury and is expected to diminish with healing and time. Chronic nonmalignant pain frequently develops following an injury but persists long after a reasonable period of healing. Its underlying causes are often not readily discernible, and the pain is disproportionate to demonstrable tissue damage. It is frequently accompanied by alteration of sleep, mood, and sexual, vocational, and avocational function. Insomnia Insomnia may be defined as a disturbance or perceived disturbance of the usual sleep pattern of the individual that has troublesome consequences.