Conditioning of physical symptoms after neurotoxic exposure.

Psychologic reactions to a neurotoxic exposure can produce prolonged physical symptoms which are as debilitating as the direct effects of the neurotoxic substance. A group of patients exist who experience reoccurrence of exposure-related symptoms when exposed to a variety of common environmental substances, such as perfume, gasoline, and cigarette smoke. We propose a classical conditioning model to explain the development of this phenomenon. Identification and treatment of these individuals are also discussed.