Screening for abnormal illness behaviour.

A screening test for detecting abnormal illness behaviour in patients with somatic symptoms is described here along with its psychometric properties. This screening version of the Illness Behaviour Questionnaire (SIBQ) is derived from two subscales of the Illness Behaviour Questionnaire and has 11 items. The study was carried out on 78 consecutive patients with prominent somatic complaints and 22 normal volunteers. The SIBQ was administered to the subjects and the sensitivity, specificity and hits positive rates were computed for different cut-off scores. A score of 7 and above gave a sensitivity of 86%, a specificity of 83% and a hits-positive rate of 0.7537, and this seems the optimal cut-off score. The SIBQ may prove to be a sensitive screening instrument to detect probable cases of abnormal illness behaviour and especially useful for busy clinics or centres.