Oxytocin gene partly responsible for how adolescents feel

Oxytocin is a hormone with an important role in social behavior. In the period following birth, it is an important factor in the bonding process between mother and baby, but it also has an influence on other relationships. The gene that regulates oxytocin-sensitivity in the brain varies between one person and another. Some people are less sensitive to oxytocin and therefore more likely to feel lonely. Various indicators have already suggested this. This prompted a group of behavioral researchers in Nijmegen to carry out a fresh and in-depth study of oxytocin effects in a group in which 'belonging' is of paramount importance: young adolescents.

A large group, frequently surveyed

The study involved 278 adolescents, 58 per cent of whom were girls. They were contacted via their smartphones nine times a day over a six-day period and asked to report how they felt and who they were with. The presence of the variant of the oxytocin receptor gene OXTR was also determined. 'This is a new approach to researching the interaction between gene variation and the environment,' explains Eeske van Roekel, the lead author of the article published online in PlosONE on Monday 4 November. 'By asking the subjects nine times a day "How do you feel? Who are you with? What do you think of the people you are with?," we managed to put together a clear picture of how adolescents feel in everyday life. These real-time reports are more reliable than responses after the event.'

Lonelier with specific OXTR variant

'Our most important finding was that girls who carried a certain variant of the oxytocin gene in their DNA felt lonelier than girls who did not. Boys with this variant were also adversely affected by negative company at the weekend: their feelings increased the longer they were in such company, while boys without this variant were unaffected. These findings apply to both boys and girls.' The measured effects are small but still relevant, says Van Roekel. 'These methods reveal more about actual everyday experiences than methods that ask people once at a later date to describe how they felt.' Heightened sensitivity to negative company in the case of this specific variant was only visible at weekends. How can that be explained? 'We surmise that it's because you have more freedom in the weekend to choose the people you mix with than through the week,' says Van Roekel. 'Then it makes a deeper impression if they treat you in a negative manner.'

New trend

No-one knows yet exactly how the receptor gene works. 'We still don't know how it translates into, for example, oxytocin levels in the brain,' says Van Roekel. 'So more research is needed on that front.' Research on connections between genes and behaviour is developing gradually. 'We think that our approach, which takes multiple measurements in the daily life of adolescents, has a lot to offer when it comes to discovering connections.' Van Roekel conducted her research in the group of Professor Rutger Engels at the Behavioural Science Institute of Radboud University Nijmegen.