Psychological models of development of idiopathic environmental intolerances: Evidence from longitudinal population-based data.

The origin of idiopathic environmental intolerances (IEIs) is an open question. According to the psychological approaches, various top-down factors play a dominant role in the development of IEIs. The general psychopathology model assumes a propensity towards mental ill-health (negative affectivity) increases the probability of developing IEIs. The attribution model emphasizes the importance of mistaken attribution of experienced somatic symptoms; thus, more symptoms should lead to more IEIs. Finally, the nocebo model highlights the role of expectations in the development of IEIs. In this case, worries about the harmful effects of environmental factors are assumed to evoke IEIs. We estimated cross-lagged panel models with latent variables based on longitudinal data obtained at two time points (six years apart) from a large near-representative community sample to test the hypothesized associations. Indicators of chemical intolerance, electromagnetic hypersensitivity, and sound sensitivity fit well under a common latent factor of IEIs. This factor, in turn, showed considerable temporal stability. However, whereas a positive association was found between IEIs and increased somatic symptoms and modern health worries six years later, the changes therein could not be predicted as hypothesized by the three psychological models. We discuss the implications of these results, as well as methodological aspects in the measurement and prediction of change in IEIs.