Brooding rumination predicts lower cognitive functioning in late-life depression: multivariate multiple regression analyses.

Introduction: Late-life depression (LLD) is associated with cognitive deficits, particularly in memory and executive functions. Rumination, namely brooding, may also negatively impact cognition. Few studies have investigated multivariate relationships between depressive symptoms and different types of rumination on cognition in LLD, which was the focus of the current study. We also explored whether relationships differed by gender and depression age of onset.

Method: Cognition was measured via five cognitive composites (Attention/Working Memory, Processing Speed, Language, Episodic Recall, and Executive Functions). LLD who completed both the Montgomery Asberg Depression Rating Scale (MADRS) and Ruminative Responses Scale (RRS) was used in analyses (n = 91). RRS subscales included Brooding and Reflection rumination. Two separate bootstrapped multivariate multiple regressions examined whether MADRS, Brooding, or Reflection, and their respective interactions predicted cognitive performance after covariate adjustments and Bonferroni correction. Exploratory analyses using similar models but stratified by gender and depression age of onset were also conducted.

Results: Only Brooding significantly predicted cognitive performance in the multivariate omnibus models (F(7,78) = 3.52, p = 0.006). Follow-up univariate analyses showed significant relationships for Language (p = 0.005, BCa 95% CI [-0.09 to -0.02]) and Episodic Recall (p < 0.001, BCa 95% CI [-0.012 to -0.04]) domains, with higher Brooding associated with lower cognitive performances. Exploratory analyses demonstrated a significant multivariate effect of Brooding in both men and women; however, the only significant univariate effect was for Episodic Recall in women (p = 0.025, BCa 95% CI [-0.11 to 0.01]). Age of depression onset was not significant for any of the multivariate models.

Conclusion: Elevated Brooding (and not depressive symptoms, Reflection rumination, or their interactions) was associated with lower language and memory functions in LLD. This effect may be greater in women, particularly for memory. Interventions aimed at improving brooding rumination in LLD may also benefit cognitive performance.