Background: Social isolation is a well-documented, modifiable risk factor for dementia, linked to cognitive decline and reduced cognitive reserve (Huang, 2023; Drinkwater et al., 2022). Using Drosophila melanogaster, given its functional homology with human stress-related neurotransmitters (Sokolowski, 2010), we tested whether early socialization protects behavioral stability against later isolation, explicitly accounting for sex.

Methods: Subjects were Drosophila melanogaster (Canton-S), 106 individuals, both sexes, recorded at 1 and 4 weeks of adulthood. Three social histories were compared: chronic isolation (Group A), early socialization followed by isolation (Group B), and continuous socialization (Group C). Behavioral measures were obtained from a 10-minute video in a standardized grid: crossings, direction changes, jumps, and resting episodes. Statistics: three-way ANOVA (Group × Age × Sex, Type III SS), with Welch's ANOVA and Games-Howell post-hoc for variance heterogeneity; negative binomial GLM for jumps (overdispersed). R v4.6.0.

Results: Effects emerged only at 4 weeks. Crossings showed significant Group and Age effects (males: B>C; females: A>C). Direction changes showed a highly significant Group×Age×Sex interaction (males: A>B and A>C; females: B>A). Jumps showed a Group effect (males: A>C, rate ratio=9.9; B>C, rate ratio=17.8). Resting episodes showed the study's strongest three-way interaction, reversed by sex at 4 weeks (males: A>B; females: B>A and C>A). Effect size was largest for Age in resting episodes, followed by Group×Age×Sex interactions in resting episodes and direction changes.

Conclusions: These findings support the hypothesis that prior socialization modulates isolation's behavioral effects, depending on timing and sex (Yadav et al., 2024). Effects emerging only at 4 weeks suggest accumulation with sustained isolation, paralleling cognitive decline in isolated older adults. Dementia prevention should not be limited to late adulthood: early socialization may also protect long-term behavioral trajectories. This study is limited by group imbalance and the absence of neurochemical data, which planned HPLC quantification will address.