Genetic Differences and Relationship Intervention

We know from years of research that communication problems are a primary issue for many couples. Studies show that a communication style that is overly negative, with yelling, name-calling, and contempt, is a significant predictor of divorce. Thus, many interventions for couples include some kind of training in communication skills.
Text: Michael Pluess and Galena Rhoades

One programme of this kind is the Prevention and Relationship Education Program or PREP. It is different from therapy in that it is offered in a class or workshop format and because it is worthwhile not only as a programme for couples who are in distress or not communicating well, but also for couples who would simply like to improve their communication in a preventative approach. Oftentimes couples receive PREP premaritally. The programme includes 12 hours of material on skills and techniques for communicating as well as ways to maintain fun and friendship in relationships, commitment, and intimacy. PREP has been translated into many different languages and studied in several different countries. According to these studies couples who receive PREP tend to communicate better and are less likely to divorce than couples who do not receive this educational programme.

Genetics influence environmental sensitivity

One might presume that people will generally respond similarly to psychological intervention and that all couples participating in PREP or similar programmes will experience the same positive intervention effects. However, over the last years new theories have been developed suggesting that people differ substantially in their response to intervention with some benefitting more than others. One reason for such differences is that people generally vary in their sensitivity to environmental influences and experiences. In other words, some people happen to be more sensitive to their environment and are therefore shaped more strongly by what they experience while others appear less sensitive with environmental influences having smaller effects on them. What makes some people more sensitive than others? According to the latest research findings environmental sensitivity has a genetic basis which is reflected in both psychological and physiological characteristics. Although most people share the same genes some of these genes come in slightly different versions and some gene versions have been found to increase people’s sensitivity to environmental conditions. While the idea that people differ in their environmental sensitivity is now widely accepted in the field of developmental psychology, it has never been tested whether genetically more sensitive individuals will benefit more from psychological intervention programmes like PREP than genetically less sensitive ones.

Intervention shows better effect on women with a certain gene type

With the support of Jacobs Foundation we are currently conducting a unique study to test, for the first time, whether genetic differences between people influence their response to the positive effects of PREP. In a first analysis we focused on a group of 70 American women who participated in a PREP study shortly before being married more than 10 years ago. Some of these women (and their husbands) were randomly allocated to PREP and some to a control condition presumed to have no particular positive effect on marital quality. After the intervention was completed these women rated their marital quality on an annual basis over the last 12-15 years. We then asked these women to provide us with saliva samples in order to determine genetic differences between them and to investigate how these differences influence their response to PREP even many years after the intervention ended. Confirming our hypothesis of genetic differences associated with environmental sensitivity, we found that women with the T/T version of the oxytocin receptor gene benefitted more from the long-term effects of the intervention than women with the C version of the same gene. The oxytocin receptor is a protein and forms part of the oxytocinergic system in the brain which plays an important role in social behaviours, including parental care, attachment and trust in other people. Although all women showed a decrease in marital quality over time, the more genetically sensitive women exhibited the least decline in marital quality if they were allocated to PREP and the strongest decline if they were in the control group. These findings provide further evidence that some people are more sensitive to their environment, including relationship intervention, than others due to genetic characteristics.

As a next step in this on-going research we will repeat these analyses with a larger sample, include both married and divorced women and men in the analysis and consider additional genetic differences. We hope that knowing more about individual differences in environmental sensitivity will enable practitioners to offer interventions that fit individual’s level of environmental sensitivity better and, hence, increase the efficacy of psychological interventions even more.