21 September 2019 | New Scientist | 15A SET of brain structures appears
to be implicated in depression,
schizophrenia and other mental
health conditions, delegates
at the European College of
Neuropsychopharmacology
annual meeting heard last week.
“We know for psychiatric
illnesses, the categories of
diagnosis are not very reliable,” says
Maxime Taquet at the University of
Oxford. Psychiatric disorders have
been shown to overlap when it
comes to which genes they are
linked to, as well as symptoms.
Taquet and his colleagues wanted
to find out how these shared genetic
factors might influence a person’s
brain structure. Looking at the
brains of adults with established
disorders might not answer the
question, as the disorder or anytreatments might have caused
changes to the brain.
Instead, his team turned to
children aged between 3 and 18,
none of whom had been diagnosed
with a psychiatric condition. Any
differences in brain structure
among children are more likely
to be explained by genes rather
than the effects of an established
disorder or treatment, says Taquet.
Using data from 678 children in
the US, the team searched for 1877
genetic factors linked to a range of
psychiatric conditions, including
schizophrenia, panic disorder and
addiction. Each child was given a
score based on their overall geneticrisk for mental health issues.
Brain scans revealed “large
differences” between the brains
of high-risk and low-risk children,
says Taquet. The team describes
the affected regions as the
“vulnerability network”, and
it includes the default mode
network, which is active when
the brain is at rest, plus regions
involved in planning and vision.
The findings add weight to
the idea that seemingly different
disorders have a lot in common,
says Taquet. “The psychiatric
disease categories we have, such
as depression, bipolar disorder,
schizophrenia and anxiety disorder,
are not that different in the end,
from a biological point of view.”
Annika Hulten, a medical adviser
for pharmaceutical firm Janssen-
Cilag in Helsinki, Finland, says the
work is “impressive and promising”.
But she says it is too soon to know
if this network would make a good
target for future treatments. ❚ JHECNP conference round-up Mental healthWOMEN with perinatal depression
appear to have altered circadian
rhythms. Using light to reset the
body clock seems to improve
their symptoms.
Our bodies run on internal
clocks that are regulated by a suite
of genes. In concert with light,
they wake us up in the morning
and leave us sleepy by night-time.
People with severe depression
tend to have disrupted circadian
rhythms, experiencing daytime
sleepiness and night-time
insomnia. Research has found
higher activity in some circadian
genes in people with the condition.
Perinatal depression – which
occurs during and after
pregnancy – seems to be similar.
Women tend to get less sleep when
they are pregnant, particularly if
they have perinatal depression.
To find out if circadian genes
might play a role, Massimiliano
Buoli and Cecilia Maria Esposito
of the University of Milan, Italy,
analysed seven genes in
44 women in the third trimester
of pregnancy. Thirty of the women
were diagnosed with perinatal
depression.
By looking at whether
epigenetic tags called methyl
groups were attached to the
genes, the researchers and their
colleagues could tell how active
these genes were. They found thatthree circadian genes were more
active and one was less active
in the women who had been
diagnosed with depression.
The team also found that the
more methyl groups there were,
the more severe a woman’s
symptoms were likely to be.
This suggests that the greater“ Four circadian genes
showed different activity
in the women diagnosed
with depression”
Jessica HamzelouGETTY IMAGESLight therapy may help relieve
symptoms of perinatal depression
Brain network linked
to multiple mental
health conditionsGenetic factors
involved in
mental health
may influence
brain structureSUDOK1/GETTYthe difference in circadian gene
activity, the more likely a woman
is to experience symptoms of
depression, say Buoli and Esposito.
The pair presented their findings
at the European College of
Neuropsychopharmacology
annual meeting in Copenhagen.“The work is tremendously
exciting,” says Katherine Sharkey
at Brown University, Rhode Island.
In her own research, Sharkey
has found that using a light
box to mimic natural daylight
improves the symptoms of
perinatal depression. In a smallunpublished trial of 44 women
with the condition, she found
that those given a light box and
sleep routine alongside routine
treatment saw their symptoms
improve. “Everybody got better,
but the women given a circadian
intervention did better [than
those without],” says Sharkey.
Sharkey doesn’t yet have
enough evidence to recommend
the treatment more widely, but
there is evidence that a good sleep
routine and outdoor exposure to
sunlight is beneficial for mental
health. “In a typical office space,
the light level is 300 to 400 lux,
but on a bright, sunny day, outside
can be 50,000 lux,” says Sharkey. ❚Circadian rhythms
appear to be disrupted
in pregnancyHear Linda Geddes talk about how sunlight shapes our bodies
and minds at New Scientist Live on 11 October
newscientistlive.com