Neuropsychological assessment, depression, and past exposure to organic solvents

This study assessed neuropsychological performance in persons with a history of exposure to organic solvents and nonexposed healthy controls. Structured clinical interviews were also done to determine current Axis I diagnosis of mood disorder to assess the contribution of mood disorder to neuropsychological performance. Solvent-exposed participants were found to have significantly reduced scores on 3 of 5 neuropsychological clusters (learning and memory, visuospatial, psychomotor speed) compared to controls. No differences were found between the groups on measures of general intelligence. Within the exposed group, 50% met current Axis I criteria for mood disorder. Hierarchical multiple regression, controlling for age and education, revealed that mood disorder was significantly related to performance on only the visuospatial domain. There was no association between mood disorder and measures of learning and memory, attention, motor speed, and general intelligence. Higher ratings of past exposure were associated with poorer scores on learning and memory tests and slower times on speeded tests. These findings are consistent with other research documenting deficits in neuropsychological and psychiatric functioning in exposed workers.