If one of your family members has a mental illness, does that mean you're more likely
to have it too? Can you inherit a mental illness from a parent?
If your mom has, let's say, social anxiety disorder and you do too, does that mean that
she passed it down genetically? Or that because she didn't take you out much and you watched
her being nervous around other people that you learned to be anxious around other people? In
this video we're going to talk about heritability estimates, what the research has to tell us about
how much genes contribute to mental health. You'll learn which disorders have the highest
rates of heritability and how understanding this can help you make better choices.
Okay. So we're going
to jump in to the numbers behind mental health heritability real quick,
but first let me clarify a few things. There are no mental health conditions
that I know of that are 100% genetic. There is no single gene for any condition that we know
of. There is not a depression gene or a bipolar gene. Mental health conditions are caused by a
whole bunch of complicated interplays between a bunch of different genes and our environment
and how we think. So the old debate, "Is it nature or nurture?" has given way to a much more nuanced
exploration of how nurture - the experiences we have - turn on or turn off various genes, nature.
Now, this is called epigenetics. So research shows that someone who experiences trauma,
for example, is much more likely to develop depression or diabetes because some genes get
turned on by those experiences, and even more, those genes that get turned on are more likely
to get passed on. So our experiences interplay with our biology in a way that scientists are
just beginning to explore. And this is called epigenetics. Right? It shows that with any set
of genes we all have a spectrum, a degree of influence within our biological inheritance.
So in my opinion life is about what we will do with what we have, how we'll
play the cards we were given, and I believe there's a lot of room for growth and change.
Now, that being said, biological influences do exist, and researchers have been able to
study this in two ways: by comparing twins and by researching people that were adopted and raised
in a completely different environment than their biological parents. So really smart statisticians
and researchers have looked at lots of data and estimated how much genetics contribute to mental
illness. Okay. So that being said, let's look at the numbers. These are the heritability estimates.
Researchers believe that depression is 30 to 42% heritable, general anxiety disorder around 31%,
panic disorder around 43%, schizophrenia between 73 and 90%, bipolar disorder between 60 and 85%,
OCD around 47%, ADHD between 60 and 80%. Pervasive developmental disorders like autism are around 90%
heritable. They're highly neurodevelopmental. But there is a spectrum of functioning with all
disorders. Anorexia they estimate between 48 and 88%, and with bulimia 28 to 83%. So you can see
with these later ones there's a lot bigger margin of error. They're not really sure how genes play
into those. So autism, schizophrenia, bipolar, and ADHD are some of the most heritable disorders,
where depression and anxiety disorders seem to be influenced more by environmental and psychological
factors. So this does not mean that 42% of your depression is caused by genes and 58% is caused
by other factors. It's way more complex than that. According to the American Journal of Psychiatry,
heritability does not really tell you how genetic a disease is but rather how important genes
are compared with other risk factors in a given population at a given time. Okay. So for example,
your height is like 90% genetic, but nutrition, injuries, illnesses, cancer on the pituitary
gland, etc., these can all impact how tall you grow. And within a single disorder like
depression, for example, some forms seem to be more heritable. So if you develop depression
at an early age, if it's recurrent, if it's more severe, or if you also have an anxiety disorder,
your depression is more likely to be genetically influenced. Okay. So what do we do with this
information? Can genetic testing tell you if you have a higher risk? The answer is no,
not yet. Right? The genetic influences are just too complicated for our level of science at this
point. But maybe one day in the future we will be able to better understand our risks through
genetic tests. Right? Um you can look at your family tree to be more informed. But just because
another family member has a condition doesn't mean you will too. So if you have a sibling
with depression, your risk is two to three times greater of having it as well. If if one parent
has schizophrenia, your chances of getting it is 10%, but if both parents have schizophrenia then
you have a 40% chance of developing the disorder. It's also important to know that predispositions
may lower the threshold. They make it so that a certain trigger is more likely to cause bipolar
in an individual with that predisposition then in someone else without that predisposition.
So genes can turn on traits during the lifespan. So what this tells me is that we should actively
provide protective factors to help people get the support and the resources they need to
lower their risk of developing mental illness. And these include, you know, good treatment,
positive support networks, education, skills, supportive families and schools,
and opportunities to experience nature and sunlight, you know, healthy routines like getting
enough sleep and exercise and good nutrition. These are all protective factors. Helping people
grow up in safe homes and neighborhoods. Right? These should be where we put much of our efforts,
and these can all help prevent the development of mental illness, then stop the cycle of mental
illness being passed down through generations. Now, again, I really don't believe that your genes
are your destiny. Each of us has so much influence over our own lives and happiness. And again,
just focus on your locus of control. Change the things that you can change, and practice accepting
the things that you can't change. If your family has a long history of abuse or mental illness,
you can be a chain breaker. You can make things better for your kids, even if it's just a little
bit better than what you experienced, and you can make things better for the people around you.
Hope you found this helpful. Thank you for watching, and take care. [Music]
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