this slide describes how we think and
understand about mental disorders today
some of the information that I'm going
to share with you in five or ten years
will not be acceptable but that's okay
because the purpose of science is to do
our best to understand this world and
sometimes as our understanding matures
based on science we have to change the
way we think we know that mental
disorders are caused by a combination of
genetic factors and environmental
factors and we know that both of them
interact on the brain to create the
probability the individual will develop
a mental disorder or may not develop a
mental disorder this creation of
probability happens at the time of
conception when part of the new
individual's DNA is inherited from the
mother and part of the individuals DNA
is inherited from the father and frankly
it's the look of the genetic dice what
parts you get from which parent you may
have mental disorder running in the
family on your mother's side but you
don't inherit that probability you may
have a mental disorder running on your
father's side of the family but you
don't inherit that probability or you
may you may inherit one or the other or
both so again it's really the role of
the genetic dice the second thing
however is the environment in utero and
this environment really matters and that
is why we try to provide the best
perinatal care we can for women to
improve optimization of the intrauterine
and
Ireland because stressors which means
anything outside of the brain affecting
the brain that come into the developing
brain in utero can have a major impact
on how that child's brain grows and
develops some of the stressors are
obvious alcohol can lead to fetal
alcohol syndrome severe protein
malnutrition may increase the risk for
schizophrenic illness different viruses
so the list is pretty long and it's
really important that as much as
possible
a healthy womb environment be provided
to all women the second part of this
interaction occurs during the birth
process anoxia that means a lack of
oxygen to the brain if it affects the
motor cortex that part of the brain that
controls your movement can be obvious
cerebral palsy is the word that we use
to describe that but if that lack of
oxygen affected the parts of the brain
that control mood or or control
different emotional states it may not be
that obvious and the next phase in this
development is the early developmental
years those first few years of life are
characterized by incredible brain
development and environmental changes
that occur during this time of life can
sometimes not always but sometimes push
brain development in one way or push it
into another way but here it's not just
the environment either it's also the
genetics plus the environment so some
people may be exquisitely sensitive to
they're in
Germans and other people much less so
sensitive to their environments so two
people both put into exactly the same
environment may have different outcomes
the point is is that we at this time
don't know how to identify which people
will be more or less responsive to
negative impacts in their early years so
our task is to try to provide the
optimal environments that we can for all
young people because as we see here in
the Maritimes a rising tide lifts all
boats
the next big phase of brain development
is during the adolescent years and here
again environmental factors and genetic
factors interact with each other and
challenges in brain development that may
have occurred earlier in utero or during
birth or in those first few years of
life may become manifest during the
adolescent years where we didn't see
them before and that can be because of
the rapid changes in brain growth and
development that occur during the
adolescent years things such as pruning
of parts of the brain of receptors that
are no longer needed also it can also it
can be the impact of the genetics that
show themselves at that time of the
developmental cycle so let me go back to
pruning if there is a genetic basis to
pruning and there is you may have
inherited a gene that prunes your brain
effectively and efficiently or you may
have inherited genes that don't prune
the brain effectively and efficiently
which could lead to mental disorders and
again it's this combination of different
environmental factors and different
genetic factors all the way through the
lifespan
which increased the probability or
decrease the probability for the onset
of a mental disorder because just as
negative life factors can perhaps push
the probability in one direction
positive life factors can perhaps push
the development into another direction
so as a result of this complex interplay
a young person may end up with no mental
disorder none whatsoever
another person may end up with some
signs and symptoms but not half the
disorder and a third person may end up
with the disorder cultural factors have
a tremendous impact not on the creation
of mental disorders but on how signs and
symptoms are expressed so for example
when I'm working in sub-saharan Africa
with young people who have psychosis
they will often have a delusional system
they will incorporate culturally
important components into that system
witchcraft for example if I'm seeing
patients at the iwk Hospital here in
Halifax they don't have that same
component although they may have a
delusional system they're much more
likely to think that someone has
implanted an electrode into their brain
and that the FBI or the CIA or some
organization such as that is controlling
how they think so in a nutshell the
probability of mental disorders is on
the basis of genetic endowment and
environmental influences that begin from
the time of conception and continue
throughout our entire lifespan