ABSTRACT
A biopsychosocial understanding of chronic abdominal pain requires integrating the biological processes affecting the pain, both peripheral and central, with knowledge of the contributing psychosocial factors (1). In effect, it is the brain-gut modulation of both enteroceptive (i.e., gut related) and extrinsic (i.e., environmental and stress related) influences on sensation that are unique to the individual. Although nociceptive signals increase with heightened motor reactivity and visceral hypersensitivity, these are not experienced as pain until they reache the brain, where central factors modulate the degree of conscious perception, even independent of gut activity. For example, pain disappears during sleep and pain can be produced in healthy individuals through hypnosis. For the clinician, an understanding of both central and peripheral processes eliciting the pain experience must be understood. This chapter will review how chronic abdominal pain exists on a continuum of severity as modulated through the brain-gut axis. For the clinician, an understanding of the degree of contribution from peripheral (i.e., visceral hypersensitivity and increased motor reactivity) and central (i.e., alteration of descending inhibitory pathways and psychosocial influences) sources will determine the diagnostic options and ultimately the plan of care.
