Computerized diary measurement of pain, disability and psychological adaptation was performed four times a day for 4 weeks in 80 patients with various duration of unexplained pain. Reported are (1) the temporal characteristics and stability of pain report during the 4-week measurement period, (2) the association between pain duration and pain report, disability and general psychopathology, and (3) the accordance between diary assessment versus questionnaire assessment of pain, disability and psychological adaptation. No evidence of instrument reactivity was found: pain report was stable across the 4-week period. However, pain report appeared to be highly variable both between and within days. About half the patients showed a clear increasing trend in pain during the day. Several differences were found between subgroups of patients varying in pain duration. Patients with less than 6 months of pain reported significantly less pain intensity, disability and fatigue than patients whose pain persisted for more than 6 months. Pain coping and responses to pain behaviors by the spouse also differed for the subgroups: longer pain duration was associated with increased catastrophizing and solicitous responses from the spouse. Comparison of scores obtained with diary versus questionnaire assessment indicated moderate correlations for most variables. Retrospective (questionnaire) assessment of pain intensity yielded significantly higher pain scores than diary assessment.
aDepartment of Medical Clinical and Experimental Psychology, University of Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands
bDepartment of Health Psychology, University of Utrecht, P.O. Box 80 140, 3508 TC Utrecht, The Netherlands
cNetherlands Institute of Primary Health Care, P.O. Box 1568, 3500 BN Utrecht, The Netherlands
* Corresponding author. Tel.:+31-43-388-1603; fax: +31-43-367-0968
Received March 18, 1999; received in revised form July 19, 1999; accepted August 2, 1999