Project I consists of two studies with the broad, long-term objectives of increasing scientific understanding of the prevalence, nature, and scope of the chronic pain problems associated with spinal cord injury and determining the most effective treatments for specific types of SCI pain. The specific aims of Study 1 are: (1) to ascertain the frequency and characteristics of chronic pain after spinal cord injury (SCI) as well as the association of such pain with physical and psychological disability; and (2) to develop a system of categorizing subgroups of patients with SCI-related problems. In Study 1, questionnaires will be administered to a large sample of people with SCI to gain knowledge concerning the types of chronic pain problems associated with SCI,in terms of pain experience, intensity, duration, and association with physical and psychological disability. Chronic pain problems will be categorized into six major classes. Study 2 is a prospective, double- blind, randomized controlled clinical trial to evaluate, as compared to placebo, the effectiveness of amitriptyline in relieving chronic pain associated with SCI. The specific aims of Study 2 are: (1) to determine pre-post treatment changes in pain and physical and psychosocial disability in people with SCI and chronic pain taking amitriptyline and placebo; (2) to evaluate whether amitriptyline is more effective than placebo in improving pain and physical and psychosocial disability; and (3) to determine the predictors of response to amitriptyline. Exploratory analyses will be conducted to determine the subgroups of individuals (and pain problems) for whom active medication may be most beneficial. These findings may be used by researchers to learn more about the mechanisms by which particular medications may improve pain problems in people with SCI.