The Impact of Rumination Induction on IQ Performance

Performance deficits on cognitive tasks consistently occur in depressed and anxious individuals. Processing efficiency theory asserts these deficits might be accounted for by task-irrelevant processes, including the negative impact of rumination. This study seeks to better understand the relationship between cognitive deficits and depression by creating a ruminative state in healthy control subjects to elicit performance deficits similar to those observed in patients with depression. Specifically, we examined the effect of rumination induction on healthy undergraduates completing select subtests of the Wechsler Adult Intelligence Scale – Fourth Edition (WAIS-IV). Participants were randomized to a rumination or distraction condition and administered WAIS-IV subtests hypothesized to be most affected by rumination and depression. Controlling for trait anxiety, individuals in the rumination condition performed more poorly on one subtest within the processing speed domain and on the Processing Speed Index score. These results support the processing efficiency model of cognitive deficits in depression, suggesting rumination induction interferes with efficient completion of mental tasks. Future research can build on these findings by studying this model in a clinical population and by continuing to improve the effectiveness of mood induction tasks for research on depression and other mood disorders.