Neurobehavioral effects of long-term occupational exposure to organic solvents: two comparable studies.

Two comparable cross-sectional studies were carried out employing the same methodology but involving two separate solvent-exposed populations (N = 90, N = 144). In each study, solvent-exposed workers were compared with age-matched controls on tests selected from the Neurobehavioral Evaluation System and on standardized questionnaire measures of symptomatology and psychiatric state. A similar pattern of results was obtained in the two studies indicating a significant effect on cognitive functioning, after controlling for confounding variables, occurring in those with more than 30 years of exposure. A more specific effect on learning processes was observed in those with more than 10 years of exposure. There were no indications in either study of a solvent-related increase in psychiatric symptoms.