Effect of olanzapine on cognition during treatment of behavioral and psychiatric symptoms in patients with dementia: a post‐hoc analysis

Abstract

This study was conducted to determine the effect of olanzapine treatment on cognition in elderly patients with behavioral and psychiatric symptoms (BPSD) associated with dementia. This was a post-hoc analysis of three randomized double-blind, clinical trials of olanzapine (n = 682) vs placebo (n = 257) in dementia patients with BPSD in long-term or continuing-care settings. One study was 6 weeks long; the other two were 10 weeks duration, and their data were combined. Patients were subgrouped according to baseline Mini Mental State Examination (MMSE) scores: Group I = 23-26; Group II = 19-22; Group III = 14-18; Group IV = 7-13; Group V = 1-6. BPSD was assessed by the Neuropsychiatric Inventory (NPI). Within-treatment group cognitive decline in patients was significant in the combined studies, but not in the 6-week study. Between-treatment cognitive changes were non-significant in the 6-week study, but showed a statistical trend in the combined studies (olanzapine, -0.78 +/- 0.19 vs placebo, -0.32 +/- 0.25; p = 0.06). In the subgroup analysis, there was a significant between-treatment difference in cognitive changes in MMSE subgroup IV in the combined studies (olanzapine, -0.63 +/- 0.26 vs placebo, 0.27 +/- 0.41, p = 0.04). Improvement in BPSD was correlated with better cognitive outcome (r = -0.2; p < 0.01). Although the overall differences in cognitive changes in patients treated with olanzapine vs placebo were small and non-significant, negative effects on cognition in some patients cannot be excluded, especially in patients with more pronounced cognitive decline or whose behavioral and psychiatric symptoms are not responding to treatment.