Management of FAP aims to provide symptom relief and improve quality of life through a multi-faceted approach both pharmacologically and psychologically. Like other chronic pain conditions, the etiology and pathophysiology are not yet well understood, but it involves a central process resulting in visceral hyperalgesia from peripheral and or central sensitization of the afferent system. Patient’s symptoms often require testing but it is a diagnosis of exclusion, and can be differentiated from other functional GI disorders using several criteria. The condition is frequently explained by dysfunctional gut motility and or dysfunctional visceral sensation. Somatic symptoms, depressive symptoms, and functional disability were assessed 2 months later. Patients often suffer from other functional morbid conditions such as fibromyalgia and migraine which altogether result in poor quality of life and increased heathcare utilization. Pediatric patients with chronic abdominal pain (n 143) and well children (n 104) completed a 5-day diary study regarding their appraisal and coping with daily stressors. It is constant or near-constant without a relationship to physiological events, but can be associated with psychosocial stressors. DEFINITION AND CLASSIFICATION OF FUNCTIONAL ABDOMINAL PAIN SYNDROME FAPS is a distinct medical disorder, part of the group of functional gastrointestinal disorders. One of these disorders, functional abdominal pain syndrome (FAPS), is the focus of this chapter. Along with other gastrointestinal functional disorders, as a group it constitutes the most common cause of abdominal pain. Some of the major ones are listed in Table 5-1. Functional abdominal pain, also known as intractable abdominal pain, is persistent stomach pain that does not resolve with usual therapeutic treatment. Functional abdominal pain is chronic and recurrent pain in the abdominal region that does not have an identifiable physical or organic cause.