Depression and anxiety are encountered on a frequent basis and their effect on cognitive processes can have significant implications for psychotherapy and neuropsychological evaluations.

Results supported several theoretical models of cognition that predict adverse effects of depression on attention ability, however the amount of variance contributed to attention performance by depression was small (51%). Results also supported predictions of Processing Efficiency Theory (Eysenck & Calvo, 1992) and the Yerkes-Dodson Law that anxiety can improve performance on attention tests.

Empirical studies of their specific effects on neuropsychological test performance are a relatively recent trend and results have been mixed due to various methodological problems (Sweet, Newman, & Bell, 1992) and their significance with respect to cognition has been questioned (Reitan & Wolfson, 1997).

The present study represented a unique contribution to this area due to its large sample size, use of standardized measures, and diverse patient populations.

The present study explored the effect of differing levels of anxiety and depression (on MMPI Scales 2 and 7) on attention performance (neuropsychological tests of attention) in 1209 cases gathered retrospectively. Referral sources included neurology, tumor clinic, epilepsy clinic, attorneys, and other allied professions.