This review synthesizes current research progress and explores the intersecting biological pathways between PMDD and AD, with a particular focus on dynamic fluctuations in estradiol (E2) and allopregnanolone (ALLO), dysregulation of the γ-aminobutyric acid (GABA)ergic system and serotonergic (5-HT) neurotransmitter systems, and sex-specific vulnerability associated with the apolipoprotein E epsilon 4 (APOE ε4) allele. This evidence concerns the gene APOE and Alzheimer disease.