Biases in perception and reporting following a perceived toxic exposure.

Reactions to chemical exposures often include fears of future illness, cancerphobia, reports of multiple chemical sensitivity, and other ill-defined complaints. Frequently, these complaints occur at levels of exposure not known to cause physiological harm. Although frequently dismissed as hysterical or hypochondriacal reactions, these complaints, along with other indefinite symptoms, may be better understood in terms of biases in perception and reporting. In this paper, we outline various sources of perceptual and response biases including prior beliefs, the media, influential others, reconstructed personal histories, self-perceptions, and the forensic environment. It is recommended that a thorough understanding of symptom-reporting and psychological distress following a chemical exposure involves consideration of these issues.