Convergent validation of the Illness Effects Questionnaire.

The Illness Effects Questionnaire, Illness Behavior Questionnaire, and visual analog scales of mood were given to 100 adults with nonmalignant headaches. Using regression analysis, scores on IBQ Disease Conviction, IBQ Irritability, and depression accounted for 50.6% of the variance in predicting IEQ scores. Scores on the Illness Effects Questionnaire correlated with the Illness Behavior Questionnaire subscales of General Hypochondriasis (.33), Disease Conviction (.60), Affective Disturbance (.49), and Irritability (.40), and also with rated depression (.38) and anxiety (.26).