One possible mechanism could be that of genetic susceptibility, for example, single nucleotide polymorphisms (SNPs) in estrogen receptor alpha (ERα) [37], and the 5-HTTLPR5 gene (promoter of the serotonin transporter) [19], which have been identified by various authors as being correlated with PMS and certain personality traits, such as neuroticism. The gene discussed is ESR1; the disease is premenstrual tension.