Chemosensory function and psychological profile in patients with multiple chemical sensitivity: comparison with odor-sensitive and asymptomatic controls.

Objective: We addressed the question if patients with multiple chemical sensitivity (MCS) differ from participants with self-reported odor sensitivity without MCS and asymptomatic controls in terms of chemosensory, cognitive, and clinical psychological endpoints.

Methods: In a clinical study 23 MCS patients, 21 participants with self-reported odor sensitivity, and 23 controls were investigated using electrophysiological and psychophysical olfactometric tests [chemosensory-event-related potentials (CSERP), olfactory thresholds, odor identification, trigeminal sensitivity]. The participants filled in a mood list, a list of complaints (BL), a Symptom Check List, a State-Trait Anxiety Inventory (STAI), and an MCS questionnaire.

Results: The olfactometric investigations revealed no significant differences between the groups. The MCS group reached significantly higher scores on negative mood states following odorant exposure, on health complaints, global indices, and the somatization subscale of the Symptom Check List, trait and state anxiety and symptoms, and triggering matters of the MCS questionnaire.

Conclusions: Our findings reveal that neither olfactory functions, nor chemosensory or cognitive olfactory information processing are impaired in MCS patients. They rather support findings of altered psychological profile and moderate psychopathology.