Effect of hormone therapy on personality traits: preliminary evidence in older men and women.

Objective: Findings concerning the effects of hormone therapy (HT) on cognition and dementia are mixed, with some trials suggesting increased harm at older ages. Personality, like cognition, changes with dementia, but no clinical trials to date have examined the effects of HT on personality traits. This study aimed to determine the effects of HT on personality traits in older men and women.

Method: Secondary data analysis was performed from randomized, double-blind, placebo-controlled cross-over studies of menopausal HT in women and testosterone therapy (TT) in men. Participants were community-dwelling cognitively normal adults (mean age = 75.2 years), including 29 men and 22 women. Three months of hormone intervention (for women, 0.625 mg/day conjugated equine estrogen with or without 2.5 mg/day medroxyprogesterone acetate; for men, 200 mg intramuscular testosterone enanthate every 2 weeks) were crossed over with 3 months of identical placebo with a 3-month washout between intervention phases. The main outcome measure was neuroticism and conscientiousness personality domains and facets assessed with the Revised NEO Personality Inventory (NEO-PI-R) after the active and placebo intervention phases.

Results: In linear mixed-effect models, HT in women decreased conscientiousness ( < 0.01) and the conscientiousness facet of achievement striving ( < 0.01), and increased vulnerability, a facet of neuroticism ( < 0.05). Testosterone in men decreased conscientiousness ( < 0.05) and the conscientiousness facet of dutifulness ( < 0.05), and increased vulnerability ( < 0.05).

Conclusion: In a preliminary study of healthy older adults, HT and TT formulations produced adverse changes in vulnerability and conscientiousness facets that parallel personality changes in dementia.