For the first time, a team of neuroscientists led by a two-time recipient of NARSAD Independent Investigator Grants, Ruth Feldman, Ph.D., of Israel’s Bar-Ilan University, has discovered at least one biological factor contributing to a presumed causal relationship between a mother’s postpartum depression (PPD) and social deficits in her young children. In a large study involving an initial recruitment of nearly 2,000 healthy, educated women who had just given birth, Dr. Feldman and her colleagues demonstrated that women who developed PPD had abnormally low levels of a key signaling molecule, a neuropeptide called oxytocin.
Found in the brain and many parts of the body, oxytocin is already known to be critical in biological processes triggered by mother-child bonding and caregiving, among other “prosocial” human activities. The new results obtained by Dr. Feldman and her team (which also included Richard P. Ebstein, Ph.D., of Hebrew University, a 2004 NARSAD Distinguished Investigator Grantee) are exciting because they show the children of depressed mothers also have below-normal oxytocin levels; and that 61 percent of such children develop depression, anxiety and conduct disorders by the age of six, when they enter school.
The study, published October 1st in the American Journal of Psychiatry, is also powerful because it shows that a mutation in the oxytocin receptor gene (OXTR)―which gives the body instructions for building receptors, or “docking ports,” for oxytocin molecules―is more common in mothers who suffer from PPD. In effect, then, the study identifies two different biomarkers whose presence indicates elevated risk for both PPD and early-childhood behavioral disorders: the OXTR gene (two copies of the mutant version in the mother’s genome greatly elevates risk; only one copy greatly diminishes the extra risk, both for mother and child); and levels of oxytocin as measured in saliva.
Even more exciting, perhaps, is the prospect that therapies which raise oxytocin levels can reverse the harmful impact on bonding that abnormally low levels engender. Dr. Feldman notes that various touch-based interventions, including massage therapy, can raise oxytocin levels in mother and, via the mother’s bonding efforts, also in her child. Other non-pharmacological therapies such as exercises in teaching infants to “synchronize” eye contact with their mothers can also raise oxytocin levels. There is also the prospect that future medications to raise oxytocin levels could be effective for those who are not producing enough.