Neuroticism, alexithymia, negative affect, and positive affect as determinants of medically unexplained symptoms

The objective of the present study was to examine the interrelationships between neuroticism, alexithymia, negative and positive affect, and medically unexplained symptoms (MUS). To this end 377 subjects, presenting to their primary care physician with MUS, filled out a questionnaire consisting of 45 non-gender-specific symptoms, the 20-item Toronto Alexithymia Scale, the NEO Five Factor Inventory, the Symptom Checklist, and the Positive and Negative Affect Schedule. To determine main effects, moderator effects and mediator effects of the independent variables on MUS, path models were constructed on the basis of multiple regression analyses. Once the dimensions of negative and positive affect were accounted for, neuroticism and general alexithymia no longer exerted a significant direct effect on MUS. Instead, their effect became indirect, mediated through negative affect (neuroticism), and positive affect (neuroticism and general alexithymia). In contrast with general alexithymia, the difficulty in identifying feelings (DIF) dimension of alexithymia had a significant direct effect on MUS. The present findings support the notion that the DIF dimension of alexithymia may be a more specific predictor of MUS than general alexithymia. The potentially important role of positive affect is also pointed out. Both dimensions deserve more attention in future research on somatization.