Cognitive and Learning Aspects

Historical Perspective

There are a number of different ways to conceptualize pain and subsequently people who experience and report pain. It is important to examine different conceptualizations of how one thinks about the person reporting pain, and the symptoms will guide the methods selected to evaluate the patient and the types of treatment initiated. Traditional views of pain have focused on somatic factors as the primary variables, with psychological factors being secondary reactions to pain. Only when physical factors were insufficient to account for the reports of pain was the role of psychological factors raised. From this perspective pain is viewed as either physical or psychological. An alternative model concerns the role of conscious motivation. Many third-party payers believe that in the absence of somatic evidence of objective pathology to account for the pain reported, the primary explanation for the complaint of pain is secondary gain such as receiving disability payments, obtaining attention, or being prescribed drugs with reinforcing properties.

Historically, the psychodynamic view and the concept of a pain-prone personality (described below) have dominated thinking about the psychology of pain. Since the mid-1960s, however, behavioral and cognitive–behavioral approaches have been formulated and risen to ascendance, becoming the dominant psychological formulations ( , ). Behavioral models explain the maintenance and generalization of pain and pain-related disability through both non-associative (habituation and sensitization) and associative (respondent and operant) learning and, in addition, through the role of a wide variety of cognitive factors. Each of the psychological perspectives is reviewed below. We also describe a biobehavioral model that attempts to integrate neurobiological features with relevant psychological variables.

Psychogenic Pain

As is frequently the case in medicine, when physical evidence and explanations prove inadequate to explain the symptoms, psychogenic alternatives are proposed. If the pain reported by a patient cannot be objectively confirmed, is judged to be disproportionate to objectively determined physical pathology, or if the complaint is recalcitrant to “appropriate” treatment, it is often assumed that psychological factors must play a significant causal role. Determination of whether the pain reported is “disproportionate” to the physical pathology identified is, however, a subjective decision by an external observer. There is no objective way to determine how much pain is proportionate and how much a given amount of tissue damage should hurt. Similarly, determination of appropriate treatments is not completely objective and is influenced by providers’ beliefs, training, and experience. Different health care providers might recommend widely different treatments for patients with the same symptoms and even diagnoses. Finally, the role of psychosocial factors requires a positive diagnosis in the sense that psychosocial factors contributing to the experience of pain must be identified. The mere absence of somatic findings can never qualify as a sufficient precondition for the diagnosis of a psychologically determined pain problem.

Several variants of psychogenic etiological models have been proposed. For example, a model of a “pain-prone personality” that predisposes people to report persistent pain was originally described by and extended by . According to Blumer and Heilbronn, the pain-prone disorder is characterized by denial of emotional and interpersonal problems, inactivity, depressed mood, guilt, inability to deal with anger and hostility, insomnia, craving for affection and dependency, lack of initiative, and a family history of depression, alcoholism, and chronic pain. People who can be characterized in this way are conceived of as being a unique group that can be considered part of the depressive spectrum. Engel proposed that once the psychic organization necessary for pain has evolved, the experience of pain no longer requires peripheral stimulation. The psychodynamic view assumes that pain may originate from psychological mechanisms even in the absence of any physiological perturbations.

proposed a model that is conceptually similar to that of . The authors suggest that difficulties expressing anger and controlling intense emotions, in particular, are the predisposing factors linking chronic pain and the experience of negative affect. They view the experiences of chronic pain and depression as similar disturbances or failure to process intensively emotional information (e.g., related to prolonged blocking or inhibition of intense interpersonal anger). Little research has been reported that supports an etiological role of the inhibition of affect in chronic pain states.

critically examined both the hypothesis of a pain-prone disorder and the empirical support for it. They concluded that the hypothesized pain-prone disorder is conceptually flawed, circular in reasoning with the definition itself tautological, and the explanatory model lacking in parsimony. In addition, they challenged the purported empirical support for the pain-prone disorder as being inadequate, inappropriate, and post hoc.

Pain Disorder

The created two psychiatric diagnoses associated with pain in the Diagnostic and Statistical Manual of Mental Disorders IV-TR : pain disorder associated with psychological factors either with or without a diagnosed medical condition. The specific diagnosis of pain disorder associated with psychological factors and a general medical condition (code number 307.89) is characterized by the fact that both psychological factors and a general medical condition have important roles in the onset, severity, exacerbation, and maintenance of pain. This set of diagnoses is so broadly defined, however, that use of these criteria will yield an excessively high percentage of patients with persistent pain in whom a mental disorder may be diagnosed.

The somatogenic–psychogenic dichotomy forms the basis for the distinction underlying attempts to identify functional versus organic groups of chronic pain patients, as well as for references to a “functional overlay.” These psychogenic views are posed as alternatives to purely physiological models. If the report of pain occurs in the absence of or is disproportionate to objective physical pathology, ipso facto, the pain has a psychological component. As discussed above, this either–or model of chronic pain must be replaced by a multidimensional view because pain always has both psychological and physiological components.

Personality of the Pain Patient

The personality of a chronic pain patient has also often been mentioned as an important pain-eliciting or pain-maintaining factor (e.g., ). The Minnesota Multiphasic Personality Inventory (MMPI) has commonly been used for diagnosis of the pain-prone personality (cf. ). Studies have, for example, attempted to identify a specific migraine or rheumatoid arthritis (RA) personality. As noted, these efforts have received little support and have been challenged ( ). Specifically, many of the measures that have been used to assess psychopathology are contaminated by items that measure the consequences of chronic illness, including medications prescribed. The result has been substantial over-diagnosis of psychopathology in chronic pain populations ( ).

In general, one can state that the existence of a pain-related personality has not been empirically demonstrated since differences in the personality profiles of chronic pain patients and healthy controls are often related to the presence of a chronic disease and the accompanying symptoms rather than to psychopathology ( ). On the basis of previous experiences, people do, however, develop idiosyncratic ways of interpreting information and coping with stress. There is no question that these unique patterns will have an effect on their perceptions of and responses to the presence of pain or pain relief. For example, reward-related personality characteristics such as novelty seeking, harm avoidance, behavioral reinforcement seeking, and reward responsiveness were found be to related to the efficacy of placebo analgesia, as well as gray matter density, thus suggesting that a change in brain structure exists in placebo activation–related brain areas ( ).

Simulation and Exaggeration of Pain

A variation of the dichotomous somatic–psychogenic view is a conceptualization that is ascribed to by many insurance companies and other third-party payers. With this view, if there is insufficient physical pathology to substantiate the report of pain, the complaint is invalid, the result of symptom exaggeration or outright malingering. The assumption here is that reports of pain without adequate biomedical evidence are motivated primarily by the desire to obtain financial gain. This belief has resulted in a number of attempts to catch malingerers via psychological tests, surreptitious observational methods, and sophisticated biomechanical machines geared toward identifying inconsistencies in functional performance. The validity of the inconsistent findings obtained on psychological measures of malingering and mechanical apparatus has been seriously challenged. No studies have demonstrated dramatic improvement in pain reports subsequent to receiving disability awards (e.g., ). Moreover, as described in detail below, operant and classic conditioning processes, which are often completely automatic and of which patients are unaware, seem to be major determinants of pain expression and pain behavior. It is important for third-party payers and insurance carriers to understand that the majority of the psychological processes affecting a chronic pain patient fall into this category of implicit or non-declarative learning ( ) that fails to enter awareness and therefore cannot be consciously manipulated by the patient. According to the report of the U.S. Social Security Commission on the evaluation of pain, active malingering is extremely rare ( ); outright malingering occurs in less than 5% of people reporting chronic pain. Given this low estimation of the presence of malingering, it would require very large samples to identify any potential predictors.