The role played by the interaction between genetic factors and attachment in the stress response in infancy.
BACKGROUND
The importance of understanding which environmental and biological factors are involved in determining individual differences in physiological response to stress is widely recognized, given the impact that stress has on physical and mental health.


METHODS
The child-mother attachment relationship and some genetic polymorphisms (5-HTTLPR, COMT and GABRA6) were tested as predictors of salivary cortisol and alpha amylase concentrations, two biomarkers of hypothalamic-pituitary-adrenocortical (HPA) axis and sympathetic adrenomedullary (SAM) system activity, during the Strange Situation (SS) procedure in a sample of more than 100 healthy infants, aged 12 to 18 months.


RESULTS
Individual differences in alpha amylase response to separation were predicted by security of attachment in interaction with 5-HTTLPR and GABRA6 genetic polymorphisms, whereas alpha amylase basal levels were predicted by COMT x attachment interaction. No significant effect of attachment, genetics and their interaction on cortisol activity emerged.


CONCLUSIONS
These results help to disentangle the role played by both genetic and environmental factors in determining individual differences in stress response in infancy. The results also shed light on the suggestion that HPA and SAM systems are likely to have different characteristic responses to stress.
Frigerio
Alessandra
A
Eugenio Medea' Scientific Institute, Italy. alessandra.frigerio@bp.lnf.it
Ceppi
Elisa
E
Rusconi
Marianna
M
Giorda
Roberto
R
Raggi
Maria Elisabetta
ME
Fearon
Pasco
P
D000328:Adult; D000483:Alleles; D002675:Child, Preschool; D005190:Family; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D007223:Infant; D008297:Male; D009034:Mother-Child Relations; D009769:Object Attachment; D010913:Pituitary-Adrenal System / Q000378:metabolism; D011110:Polymorphism, Genetic / Q000235:genetics*; D050638:Receptors, Dopamine D4 / Q000235:genetics; D011963:Receptors, GABA-A / Q000235:genetics*; D012469:Salivary Glands / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D013315:Stress, Psychological / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism
C546171:GABRA6 protein, human; D011963:Receptors, GABA-A; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D050638:Receptors, Dopamine D4; D000516:alpha-Amylases; D006854:Hydrocortisone