Korean Journal of Biological Psychiatry

Objectives : This study investigated associations between symptom severity and neurocognitive functions in patients with major depressive disorder using comprehensive neuropsychological tests.

Methods : Ten patients with low depression (LD) and 22 patients with high depression (HD) participated. Symptom severity was determined by both the Beck Depression Inventory and the Hamilton Depression Rating Scale. Additionally, anxiety was measured by the Korean version of the State-Trait Anxiety Inventory (STAI-KYZ). Ten subtests of the Korean-Wechsler Adult Intelligence scale (K-WAIS), Stroop test, the word/design fluency tests were administered to assess cognition.

Results : The LD and HD groups did not differ in any of cognitive measures but anxiety level. Namely, the HD group obtained significantly higher scores on the state (U = 29.50, p < 0.01) and trait (U = 28.50, p < 0.001) anxiety scales than the LD group. A significant interaction effect between trait anxiety and depression severity was observed on the picture arrangement subtest of the K-WAIS [F (1, 27) = 5.09, p < 0.05].

Conclusions : Cognitive deficits observed in patients with major depressive disorder may be related to other factors rather than current symptom severity. Trait anxiety possibly moderates the effect of current symptom severity on social judgment in these patients.

Keywords Major depressive disorder;Severity of symptoms;Neurocognitive functions.