[Sudeck syndrome (CRPS) caused by unique personality traits: myth and fiction].

BACKGROUND: In analogy to the thesis of "pain-proneness", conceptualised by G. Engel more than 50 years ago, the idea of a unique structure in personality emerged, which was given a causal meaning in the development of Sudeck's Disease (now known as complex regional pain syndrome - CRPS), of which the pathogenesis is particularly unknown until today. It was supposed that certain psychological traits predispose one to develop CRPS. Predisposition in this context was apprehended as a personal susceptibility to produce and maintain an excessive reaction to nociceptive stimulations. This model has been maintained for a long time and was the subject of scientific examination just in the last two decades.

METHOD: Some publications reporting sporadic correlations between CRPS and certain personality traits, for example anxiety, neuroticism and depressive mood, are presented as are also 15 current empirical studies and five reviews, which deal in a more differentiated manner with the formulated question and lead to sobering results. The relevant state of research as well as the fundamental and methodical difficulties in regard to verifying a CRPS personality or pain-prone personality are discussed critically.

RESULTS: In general, there is a lack of high-quality relevant studies. Some retrospective/cross-sectional studies yield contradictory results regarding psychological problems in patients with CRPS but the majority shows no association, and studies with higher methodological quality tend to the conclusion of no relationship between psychological factors like depression, anxiety, neuroticism, or anger and CRPS. Especially, the few prospective studies do not report such a relationship, psychological factors are not associated with CRPS onset. Compared to other patients with chronic pain there is no unique disturbed psychological profile and no higher degree of psychosocial disturbance in CRPS patients. In all, the results of research cannot confirm the hypothesis of correlations between psychological and psychosocial factors and the pathogenesis of CRPS. Furthermore, there is no evidence for the existence of a unique CRPS personality or psychosocial pattern. The findings are in conformity with the outcome of research referring to the general pain-prone personality, which was abandoned due to the lack of success. It has been shown that there is a non-specific and non-linear relationship between personality and pain, there is no aetiological link. The observed modifications in behaviour and personality of CRPS patients, in particular depression and anxiety, are a consequence of the persisting pain disease and its considerable resistance towards treatment and not the cause.

CONCLUSION: Although many patients with CRPS have been stigmatised as being psychologically different, a relationship between this disease and several psychological factors cannot be derived. The idea of an existing "Sudeck personality" as well as the search for such a predisposing personality structure are obsolete and useless. Management of pain and pain-related impairments, however, are based on the personality of the affected persons.