Test of the Serotonin Transporter Gene × Early Life Stress Interaction Effect on Subjective Well‐Being and Loneliness Among Japanese Young Adults

Abstract

AbstractThis study investigated whether aspects of early life environment (quality of parental relationship, frequency of parental violence including disciplinary violence, amount of parental attention, and family income during childhood) would affect one's subjective well‐being and loneliness later in life (i.e., during young adulthood). This study also investigated whether the negative influence of early life stress is greater among individuals with the SS genotype of the serotonin transporter‐linked polymorphic region (5‐HTTLPR) in the serotonin transporter gene. Participants were 568 university students whose genotypes were identified using nail samples. They reported their current levels of subjective well‐being and loneliness as well as their recollections of their early family environments. The results showed that less stressful early life environments, such as high levels of parents' relationship quality and parental attention, were positively (negatively) associated with subjective well‐being (loneliness), while frequent parental violence was negatively (positively) associated with subjective well‐being (loneliness). Nevertheless, the gene × environment interaction effects were consistently non‐significant—the SS genotype did not accentuate the effects of early life stress.