Clinical and psychological diversity of non-specific low-back pain. A new approach towards the classification of clinical subgroups.

This study explored the clinical and psychological features of non-specific low-back pain (LBP) using multivariate statistical methods including correspondence analysis, cluster analysis and discriminant analysis. An unselected population of subjects (n = 330) complaining of localized LBP to hospital rheumatologists during 1988 was studied. 41% of the subjects (n = 136) were classified as having a psychiatric disorder according to the DSM-III criteria (Axis I). A number of different organic syndromes were identified and the importance of psychological influences on the clinical presentation of LBP was demonstrated. Cluster analyses provided further evidence for a four-group typology of LBP, which may be interpreted through the relationships or interactions between psychological disturbances and the clinical features of LBP. This study highlights the need, in etiological research, to take into account the clinical diversity of non-specific LBP and to investigate further the complex relationships between psychological disturbances and back pain.