The Iowa follow-up of chemically sensitive persons

Clinical symptoms and self-reported health status in persons reporting multiple chemical sensitivities (MCS) are presented from a 9-year follow-up study. Eighteen (69%) subjects from a sample of 26 persons originally interviewed in 1988 were followed up in 1997 and given structured interviews and self-report questionnaires. In terms of psychiatric diagnosis, 15 (83%) met DSM-IV criteria for a lifetime mood disorder, 10 (56%) for a lifetime anxiety disorder, and 10 (56%) for a lifetime somatoform disorder. Seven (39%) of subjects met criteria for a personality disorder using the Personality Diagnostic Questionnaire-IV. Self-report data from the Illness Behavior Questionnaire and Symptom Checklist-90-Revised show little change from 1988. The 10 most frequent complaints attributed to MCS were headache, memory loss, forgetfulness, sore throat, joint aches, trouble thinking, shortness of breath, back pain, muscle aches, and nausea. Global assessment showed that 2 (11%) had "remitted", 8 (45%) were "much" or "very much" improved, 6 (33%) were "improved", and 2 (11%) were "unchanged/worse". Mean scores on the SF-36 health survey showed that, compared to U.S. population means, subjects reported worse physical functioning, more bodily pain, worse general health, worse social functioning, and more emotional-role impairment; self-reported mental health was better than the U.S. population mean. All subjects maintained a belief that they had MCS; 16 (89%) acknowledged that the diagnosis was controversial. It is concluded that the subjects remain strongly committed to their diagnosis of MCS. Most have improved since their original interview, but many remain symptomatic and continue to report ongoing lifestyle changes.