Discordant peripheral levels of brain-derived neurotrophic factor and serotonin are associated with enhanced emotional intelligence in men

Emotional intelligence (EI), a normally-distributed, multi-faceted construct, encompasses the abilities to perceive, understand, regulate, and use emotions adaptively. As low EI is a risk factor for mood disturbance, there is clinical value in mapping its biological contributions. Although the neurochemistry and neurogenetics of mood disorders, particularly with respect to brainderived neurotrophic factor (BDNF) and serotonin (5-HT), are well studied, the relationship between these neurotransmitters and facets of emotion processing across the full EI continuum is unknown. In this study we tested for associations between peripheral levels of BDNF and 5-HT, as well as behaviorally relevant BDNF and 5-HT interactions, and dimensions of EI in 74 healthy adults. Urinary neurotransmitter levels adjusted for creatinine concentration were determined via enzyme-linked immunosorbent assay, and performance-based EI was measured with the Mayer-Salovey-Caruso Emotional Intelligence Test Version 2.0. Results found that BDNF and 5-HT levels were uncorrelated and that neither alone predicted EI. However, in men there was a BDNF x 5-HT interaction such that those with discordant combinations of neurotransmitter levels (high 5-HT/low BDNF; low 5-HT/ high BDNF) demonstrated superior ability to understand complex emotional meanings, transitions, and situations, an effect that was not confounded by general cognitive intelligence. No interactions were present in women. These results suggest that an interaction between BDNF and 5-HT systems contributes to EI in healthy men, although the precise physiological nature of this interaction and its consequences for brain structure and function in emotion processing pathways require further study.