Abnormalities in cognitive-emotional information processing in idiopathic environmental intolerance and somatoform disorders Michael Wittho ¨ft a, * , Fred Rist b , Josef Bailer c a Department of Clinical Psychology and Psychotherapy, Johannes Gutenberg-University, Staudingerweg 9, D-55099 Mainz, Germany b Westfa ¨lische Wilhelms-University, Mu ¨nster, Germany c Central Institute of Mental Health, Mannheim, Germany article info Article history: Received 22 September 2007 Received in revised form 31 March 2008 Accepted 10 April 2008 Keywords: Idiopathic environmental intolerance (IEI) Multiple chemical sensitivity (MCS) Somatoform disorders Extrinsic affective Simone task (EAST) Selective attention Implicit association effects Emotional Stroop abstract Idiopathic environmental intolerance (IEI) represents a functional so- matic syndrome marked by diverse bodily complaints attributed to various substances in the environment. Evidence for abnormalities in affective information processing similar to somatoform disorders (SFD) has recently been found in people with IEI. In order to further investigate these cognitive-emotional abnormalities, we compared people with IEI (n ¼ 49), SFD only (n ¼ 43), and non-somatoform con- trols (n ¼ 54) with respect to their performance in the extrinsic affec- tive Simon task (EAST). This task allowed us to dissociate indicators of automatic affective associations and emotional intrusion effects of both bodily complaints and IEI-trigger words. Negative association effects toward IEI-trigger words were strongest for IEI participants. Emotional intrusion effects of symptom words were larger both in IEI and SFD than in controls. The results of enhanced negative auto- matic evaluations of IEI-trigger words and greater attention alloca- tion to symptom words support cognitive models of IEI. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Idiopathic environmental intolerance (IEI), formerly called multiple chemical sensitivity (MCS), is marked by an unspecific pattern of various medically unexplained complaints (e.g., headache, fatigue, * Corresponding author. Tel.: þ49 6131 3923707; fax: þ49 6131 3924623. E-mail address: witthoef@uni-mainz.de (M. Wittho ¨ ft). Contents lists available at ScienceDirect Journal of Behavior Therapy and Experimental Psychiatry journal homepage: www.elsevier.com/locate/jbtep 0005-7916/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.jbtep.2008.04.002 J. Behav. Ther. & Exp. Psychiat. 40 (2009) 70–84