[Personality, stress and rheumatism: methodologic considerations].

Studies which support the assumption that an "arthritis personality" is a causative factor in the development of rheumatoid arthritis are methodologically inadequate. Some are mere descriptions; others use inappropriate control groups. The investigations also suffer from failure to provide information on patients' characteristics, such as socioeconomic status and disease parameters. Although the quality of investigations concerning the etiological role of stress in the onset of rheumatoid arthritis has also been reduced by theoretical and measuring difficulties, the evidence supports an influence of stressful events. Results of controlled studies mostly refer to a comparison of group means. An own investigation shows that correlation studies are able to describe differences between groups, even if the groups do not differ significantly in their means.