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 Researchers focused on what’s known as the brain’s corticolimbic
system, the interconnected brain areas responsible for regulating
emotion that also influence depression, stress responses and memory.
They studied the brains of 35 families, including parents and their
biological children, and found the particular contours of the
corticolimbic system are more likely to be passed down from mothers
to daughters than from mothers to sons or from fathers to children
of either gender.
“While our study was not directly done in depressed families, our
findings may mean that if mothers have brain structural anomalies in
the corticolimbic circuitry, their female but not male offspring are
more likely to have similar abnormal structural patterns in the same
brain regions, which would be consistent with how depression is
linked within families,” said lead study author Dr. Fumiko Hoeft of
the University of California, San Francisco.
Previous behavioral health studies have pointed to a strong link
between psychiatric problems in mothers and similar mood disorders
in their daughters, Hoeft and colleagues note in The Journal of
Neuroscience. Animal research has also linked mothers’ stress during
pregnancy to changes in emotion-related regions of their daughter’s
brains.
For the current study, researchers examined magnetic resonance
imaging (MRI) of both parents and children to see if they could
learn more about how these associations might work.
They found correlations between mothers and daughters in regional
gray matter volume in the corticolimbic circuit including several
parts of the brain that influence emotions – the amygdala,
hippocampus, anterior cingulate cortex and ventromedial prefrontal
cortex.
These mother-daughter similarities were significantly stronger than
the associations seen between other parent-child pairs.
The findings don’t prove that mothers pass along a depression-prone
brain structure to their daughters, and the study doesn’t mean it’s
impossible for children to inherit a predisposition to mood
disorders from their fathers, the authors caution.
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Because of the relatively small sample, the current findings are
preliminary and more research is needed with more people to better
understand how and why emotional health might be inherited, the
researchers also note.
Even so, the findings offer another biological explanation for the
strong connection between depression in mothers and daughters, said
Genevieve Piche, a psychology researcher at the University of Quebec
in Outaouais who wasn’t involved in the study.
“Until now, our hypotheses were that maternal depression has a
greater influence on girls since it provides them with a model of
depressive, cognitive and interpersonal functioning and also may
elicit more caretaking behavior in girls, which subsequently could
lead them to develop depressive symptoms,” Piche said by email.
It’s also possible that women who are depressed might minimize the
risk of passing this condition to their daughters if they get
treatment to manage symptoms, Piche added.
Family characteristics, social context, parenting style and other
environmental factors can also play a role in depression, Piche
said.
“Being exposed to a depressed mother who has difficulty dealing with
her emotions as well as a high level of family conflict and
hostility may influence the child to develop more negative
emotions,” Piche said. “It’s not just an individual factor that
heightens the risk of depression, but an accumulation of many risk
factors.”
SOURCE: http://bit.ly/1QoXIBg The Journal of Neuroscience, online
January 27, 2016.
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