The author suggests that the notion that pain is purely a sensory phenomenon is flawed. That in fact, patients with pain also differ in how they behave. Persons with pain report higher levels of physical and emotional distress, and suffering. The author proposes that persons in pain also act differently from persons without pain. Facial expressions, moans or sighs, guarding or rubbing the affected body part, altered gait pattern are typical behaviors. As behavioral programs are being increasingly recognized as part of pain treatment, the author feels that the conceptualization of pain should also include behavior as a defining feature.
Pain behavior is described as specific body movements enacted during the experience of pain. Two main behavior systems include a communicative behavior system and a protective behavior system. Behaviors that display distress relate information about the internal state of the individual, physical limitations, and needs for assistance. Facial grimacing and vocalizations such as groans and sighs are examples. Protective pain behaviors are those actions that are intended to reduce the likelihood of further injury, reduce the experience of pain, or are perceived to promote recovery from injury.
Research has shown that persons with underlying depression, or those who tend to catastrophize will display more intense facial responses to painful stimuli. The most common protective pain behavior is withdrawal. Protective behaviors can be reflexive or can be a more dramatic, larger display of behavior. Behaviors that function to protect, or promote recovery after injury include such things as holding or guarding the body part, guarding or minimized movements, altered gait. Protective pain behaviors such as avoidance of activities that are associated with pain can be a major contributor to disability.
The author feels that the dysfunction that is manifest in behavioral systems may be functionally separate from pain sensation. Therefore, treatments geared to reducing pain sensation may not be effective. He proposes that classifying the various dimensions of pain behavior into profiles would promote tailoring of interventions with the hope of reducing disability.