Association between salivary serotonin and the social sharing of happiness

PLoS One. 2017 Jul 6;12(7):e0180391. doi: 10.1371/journal.pone.0180391. eCollection 2017.


Although human saliva contains the monoamine serotonin, which plays a key role in the modulation of emotional states, the association between salivary serotonin and empathic ability remains unclear. In order to elucidate the associations between salivary serotonin levels, trait empathy, and the sharing effect of emotions (i.e., sharing emotional experiences with others), we performed a vignette-based study. Participants were asked to evaluate their happiness when they experience several hypothetical life events, whereby we manipulated the valence of the imagined event (positive, neutral, or negative), as well as the presence of a friend (absent, positive, or negative). Results indicated that the presence of a happy friend significantly enhanced participants' happiness. Correlation analysis demonstrated that salivary serotonin levels were negatively correlated with happiness when both the self and friend conditions were positive. Correlation analysis also indicated a negative relationship between salivary serotonin levels and trait empathy (particularly in perspective taking), which was measured by the Interpersonal Reactivity Index. Furthermore, an exploratory multiple regression analysis suggested that mothers' attention during childhood predicted salivary serotonin levels. Our findings indicate that empathic abilities and the social sharing of happiness decreases as a function of salivary serotonin levels.

MeSH terms

  • Adolescent
  • Adult
  • Empathy / physiology*
  • Female
  • Friends
  • Happiness*
  • Humans
  • Interpersonal Relations
  • Male
  • Regression Analysis
  • Saliva / chemistry*
  • Saliva / physiology
  • Serotonin / physiology*


  • Serotonin

Grant support

This work was supported by a JSPS Topic-Setting Program to Advance Cutting-Edge Humanities and Social Sciences Research (Responding-to-Real-Society) (to KI). This work was also supported by Kobe University (Young Scholar Award) (to YO). The funders had no role in study design, data collection or analysis, the decision to publish, or preparation of the manuscript. No additional external funding was received for this study.