Olanzapine Dosing in Women with First-Episode Psychosis: An Age-Based Proxy for Menopausal Status

Some women experience their first episode of psychosis (FEP) in mid-to-later life, including around menopause. Emerging evidence suggests reduced treatment response at this time. However, menopause is rarely considered in treatment guidelines. This study examined whether women experiencing FEP after menopause were prescribed higher olanzapine doses than younger women, using age as a proxy for menopausal status.

A population-based cohort of individuals aged 18-64 presenting with FEP to a Dublin mental health service over 18 years was analyzed. Participants who received an adequate olanzapine trial (≥6 weeks) for FEP were included. Women were stratified by age: <51 years (assumed premenopausal) and ≥51 years (assumed postmenopausal). Mean maximum daily olanzapine doses were compared. Analyses were repeated in men.

Of 396 individuals presenting with FEP, 218 met inclusion criteria. Women aged ≥51 (n = 16) received higher olanzapine doses compared to younger women (n = 78) (15.3 mg ± 6.4 vs 12.4 mg ± 5.4; mean difference 2.9 mg, 95% CI, -0.10 to 5.99, one-sided P = .029, d = 0.53). No age-related dose differences were observed in men (n = 124).

Women presenting with FEP after assumed menopause were prescribed higher olanzapine doses than younger women. This finding should be interpreted cautiously due to the small sample size and inference of menopausal status from age. However, this aligns with emerging evidence suggesting antipsychotic response may reduce following menopause. If replicated, these findings may have important clinical implications for guiding psychosis treatment in mid-life women.