The hormone oxytocin – which promotes pair bonding, maternal care, and reproductive behavior in mammals – also regulates emotions. To have effects, oxytocin must bind to its receptor.
Numerous studies have reported that persons with the nucleotide G (guanine) in a certain noncoding position of the oxytocin receptor gene tend to be more trustful, optimistic, and empathetic than persons with an A (adenine), although the underlying mechanism is poorly understood.
Robyn McQuaid, Opal McInnis, and colleagues from Carleton University, Ottawa, report that adults with G in one or both copies of the oxytocin receptor gene are also more likely to show depressive symptoms if they suffered from maltreatment (e.g. abuse or neglect) during childhood, possibly because they are more negatively affected by a breach in trust.
The researchers conclude that the G variant of the oxytocin receptor gene is not always advantageous: persons with one or two copies of this variant may thrive in a positive social environment, but they are more affected by negative experiences in early life.
Article: DOI:10.3389/fnins.2013.00128