Influence of 5-HTT, COMT, and BDNF functional polymorphisms and their interaction with parental bonding in attachment anxiety, among adults with personality disorders

Abstract

Background and objectives

Attachment is the tendency of human beings to create strong affective bonds towards specific figures, and has been described as a general vulnerability factor to diverse forms of psychopathology. Although attachment research has not tended to emphasize genetic contribution, heritability is estimated at 36–45 %. We explored the association between 5-HTTLPR, COMT Val158Met and BDNF Val66Met functional polymorphisms with attachment dimensions, as well as the gene-environment interaction, considering the perceived parental rearing styles, with both a vulnerability and a differential susceptibility approach.

Methods

150 outpatients with a cluster B personality disorder participated in the study. Attachment was assessed using Experiences in Close Relationships-Revised and rearing styles by means of the Parental Bonding Instrument. Genotypes were analyzed using saliva samples. Statistical analyses were carried out with general linear models.

Results

COMT ValVal homozygotes and BDNF Met-carriers were associated with significantly higher scores in attachment anxiety (COMT: ValVal 4.95±1.25 vs Met-carriers 4.42±1.30, t=-2.096, p=0.038; BDNF: ValVal 4.38±1.31 vs Met-carriers 4.95±1.24, t = 2.833, p=0.005). From a differential susceptibility approach, plasticity genotypes were identified for the three functional polymorphisms, observing significant interactions with parental overprotection and differential outcomes in relation to attachment anxiety. No associations or interactions were found with regard to attachment avoidance and the care dimension.

Conclusion

Our results suggest that there are individuals more susceptible to rearing experiences in terms of adult attachment outcomes, which probably also implies a greater potential to benefit from environmental and psychotherapeutic interventions.