We investigated the sex ratio trajectory across the lifespan in patients with psychogenic nonepileptic seizures (PNES). We hypothesized that there are significant changes in the trajectory of the sex ratio in these patients across the lifespan with respect to the age at onset.
In this retrospective study, all patients with PNES, who were diagnosed at Shiraz Comprehensive Epilepsy Center, Iran, from 2008 until 2019, were investigated. We arbitrarily categorized the patients into five groups according to the age at onset of their PNES [pre-puberty (≤ 14 years), adolescence (15 years to < 19 years), young adulthood (19-25 years), adulthood (26-45 years), and post-menopausal (≥ 46 years)].
During the study period, 275 patients with PNES-only had the inclusion criteria. The sex ratios (female to male) of the studied groups according to the age at onset of PNES were as follows: pre-puberty (13:14 = 0.93), adolescence (32:21 = 1.52), young adulthood (54:33 = 1.64), adulthood (71:26 = 2.73), and post-menopausal (7:4 = 1.75). In two-by-two comparison of the group with the lowest sex ratio (pre-puberty) and the group with the highest sex ratio (adulthood) the difference was significant (p = 0.01).
We postulate that the higher prevalence of PNES in women may be partly associated with lifetime sex hormone fluctuations; this female preponderance appears during puberty and decreases after menopause. However, most likely this is only one of many potential reasons behind this sex difference; therefore, this is an interesting avenue for future studies.