The effect of atorvastatin on cognition and mood in bipolar disorder and unipolar depression patients: A secondary analysis of a randomized controlled trial

OBJECTIVES: Statins have recently been linked to having effects on cognition and mood in mood disorders, though results are mixed. In this paper, we use data from a recent randomized controlled trial (RCT) to examine the effect of statins on cognition and mood in patients with Bipolar Disorder (BD) and Major Depressive Disorder (MDD).

METHODS: This is a secondary analysis of a randomized, double-blind, placebo-controlled clinical trial (n = 60) originally designed to examine the effect of atorvastatin (n = 27) versus placebo (n = 33) for lithium-induced diabetes insipidus in BD and MDD patients who were using lithium. For this analysis, the primary outcome was global cognition Z-score at 12-weeks adjusted for baseline. The secondary cognition outcomes were (1) Screen for Cognitive Impairment in Psychiatry (SCIP), and (2) executive function Z-score. The primary mood outcome (secondary outcome of this analysis) was depression relapse during 12-week follow-up (Mongomery Asberg Depression Rating Scale (MADRS) ≥10). The secondary mood outcomes were (1) relapse rate into a manic episode, and (2) relapse rate into any mood episode.

RESULTS: After 12 weeks follow-up, atorvastatin and placebo groups did not differ in terms of global cognition Z-score (β = -0.009287 (-0.1698,0.1512), p-value = 0.91). Similarly, composite Z-scores for SCIP and executive functions did not differ significantly. Depression relapse during 12-week follow-up was not significantly different between the groups (χ2 (1) = 0.148, p-value = 0.70). Similarly, there was no difference between groups regarding relapse into mania.

CONCLUSION: In BD and MDD patients with lithium-induced nephrogenic diabetes insipidus randomized to atorvastatin or placebo, we found no significant differences in cognition and mood outcomes at 12-week follow-up.