New study reveals environment's role in post-natal depression
Posted on 19 May 2011
New research involving the University of York explores the interplay between genes and environment when determining whether a mother is at high or low risk for post-natal depression.
As
part of the continuing Fragile Families and Child
Wellbeing Study, launched in 1997,
researchers, including Professor John Hobcraft, of York’s Department of Social
Policy and Social Work and academics from Princeton, Penn State and Columbia Universities in the USA, examined the DNA of more
than 1,200 mothers.
Our findings on the interplay between
genetic markers and socioeconomic disadvantage regarding post-natal maternal
depression break new ground
Professor John Hobcraft
The
authors examined two genetic markers– 5-HTTLPR and Stin2 –that have been linked
to risk of depression. These data were then examined against whether or not the
mother was depressed in the first year of her child’s life and her level of
education – with low levels of education being a proxy for a negative
environment and higher levels for a positive one.
The
research is published in Proceedings of the National Academy of Sciences
(PNAS).
While
post-natal depression affected less than a quarter (17 per cent) of those
sampled, the rates varied depending on whether the mother carried specific
variants of a gene associated with biological sensitivity to her
environment and her level of
education.
- Not surprisingly, mothers
with genetic markers that made them more sensitive to their environment were
more likely than other new mothers to become depressed if they were in a
negative environment (ie low level of education).
- Mothers
without these markers looked the same across the education spectrum, with rates
of depression the same regardless of environment. For these mothers, environment did not seem
to have much of an impact.
- However,
when a mother with the ‘sensitive’ markers was in a positive environment (ie
high level of education) she was actually less
likely to become depressed than all other mothers, including those without
the environmentally sensitive genetic markers.
- Thus, the
term “depression gene” is not quite right. In fact, the genetic markers previously linked with depression are
actually signaling a more environmentally sensitive genetic makeup. This
results in mothers with the sensitive genetic make-up actually being better off
than other mothers in a positive environment, but worse off than others in
harsher environments.
Professor Hobcraft
said: "Our findings on the interplay between
genetic markers and socioeconomic disadvantage regarding post-natal maternal
depression break new ground. Of key importance is the evidence that mothers
with a particular combination of genetic markers do not seem to be all that
affected by environmental disadvantage, but those with a different combination
on the same gene are both less susceptible to maternal depression when
advantaged but even more at risk of maternal depression when
disadvantaged."
Lead
author, Colter Mitchell, of the Center for Research on Child Wellbeing and
Office of Population Research, Princeton University, said: “The specific
findings of this study are very interesting. But the paper is important because of the bigger concept it
demonstrates. That is, certain genes may
have a positive or negative effect depending on a person’s environment.”
Notes to editors:
- The paper "The Role of Mother's Genes
and Environment in Postpartum Depression," is published in Proceedings of the National Academy of
Sciences.
- It was
a collaborative effort by Colter Mitchell, Center for Research on Child Wellbeing
and Office of Population Research, Princeton University; Daniel Notterman,
Princeton University and College of Medicine, Pennsylvania State University;
Jeanne Brooks-Gunn, Teachers College and the College of Physicians and
Surgeons, Columbia University; John Hobcraft, Department of Social Policy and
Social Work, University of York; Irwin
Garfinkel, School of Social Work, Columbia University; Kate Jaeger, Center for
Research on Child Wellbeing and Office of Population Research, Princeton
University; Iulia Kotenko, Department of Molecular Biology, Princeton
University; and Sara McLanahan, Center for Research on Child Wellbeing and
Office of Population Research, Princeton University.
- More about the University of York’s
Department of Social Policy and Social Work at www.york.ac.uk/spsw/.