- Can you inherit Depression or Bipolar Disorder?
That's what I'm gonna be talking about today.
I'm Dr. Tracey Marks, a psychiatrist,
and I publish weekly videos on Mental Health education
and self-improvement.
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This video is based on a viewer question from Jaynie.
Thank you, Jaynie.
And here's the question.
Here's what I told Jaynie.
For Bipolar Disorder, there's a lifetime risk
of a half to 1%, for anyone,
whether you have a relative with it or not.
If you have a first-degree relative with the disorder,
the risk goes up to 15 to 30%.
- What does that mean?
- Let me explain.
The genetics with most illnesses do not follow
Mendelian genetics.
Mendelian genetics is what you learned in science class,
where you can predict a certain trait based on
what traits the parents have.
The easiest example of a disorder that results
from Mendelian genetics, or follows it,
is Sickle Cell Anemia.
And here's how it works.
And this is a basic, quick primer on genetics,
it's not all-inclusive.
Sickle Cell Anemia represents a genetic mutation
on a gene responsible for producing red blood cells.
Each person has two chromosomes that have this gene on it.
You get one from your father and one from your mother.
You need two copies of the mutated gene to have Sickle Cell.
So, if you do not have Sickle Cell Anemia,
you either have two normal genes,
or, one on each chromosome,
or, one normal chromosome and one mutated chromosome.
So, let's say two people have a child,
and the husband has Sickle Cell Anemia and the wife does not
but she's a carrier of the mutated gene.
If these two people have a child,
there's four possible pairings that can take place.
But there's two possible outcomes.
This couple has a 50% chance of having a child
who is a carrier, and a 50% chance of having a child
with Sickle Cell Anemia.
- What's this got to do with Bipolar?
- This is just to show you how basic inheritance works
when there's an illness that's the result from
a single genetic mutation.
Bipolar Disorder and Depression
can't be predicted like this.
We don't know exactly how the disorder comes about.
But it's thought to be a combination
of several genetic variations that come together
to increase the risk of developing the disorder.
So how would we even know what the risk is?
One of the ways we estimate risk
is by studying families and twins.
Twin studies give good information because
twins share the same DNA.
But not all twins development the same illnesses.
(crickets chirping)
So, back to the risks.
It matters if the relative who has the disorder
is first-degree or second-degree.
A first-degree relative is someone who shares 50%
of your DNA, and this would be a parent or a sibling.
A second-degree relative is someone with whom you share 25%
of your DNA, and this would be a grandparent,
uncle, aunt, niece, or nephew.
You have a higher chance of developing the disorder
if a first-degree relative has it.
And less of a chance if it's a second-degree relative.
So with Bipolar Disorder, anyone has a 1% chance
of developing Bipolar Disorder.
But if your parent or sibling has the disorder,
your risk increases to about 15%.
If you have two first-degree relatives with it,
like your mother and your brother,
your risk increases up to 75% of developing it yourself.
Major Depression, or Unipolar Depression,
is thought not to be as inherited as Bipolar Disorder.
Meaning, it's not quite as passed down as strongly
as Bipolar Disorder is.
Unipolar Depression means that you have depressive episodes,
but you don't have any manic episodes.
But, it still runs in families,
and the risk in the general population
for anyone to develop Major Depression
is between eight and 16%.
So, that's a higher percentage than Bipolar Disorder.
That means more people actually have Major Depression
than do Bipolar Disorder.
If you have a first-degree relative with Depression,
that risk increases about two to four times, which is
16 to 50% chance of you getting Depression yourself
at some point in your lifetime.
- What's the final answer?
The final answer is, if you have a parent or sibling
with either Depression or Bipolar Disorder,
you are at greater risk of developing the disorder yourself,
but it doesn't automatically mean you will get it.
It just means that you, more than someone else,
may have the disorder at some point in your life.
But, so you're risk is greater than just someone
in the general population, but it's not an automatic.
And to directly answer Jaynie's question,
who's asking about her grandchild,
because your grandchild is second-degree,
what's more important, really, is whether or not
your daughter is effected.
So, yes, your grandchildren have a greater chance
than someone in just the general population
without a relative with the disorder,
but it's not as great if your daughter is not effected.
Another tidbit here is that,
just as these disorders can run in families,
responses to medications can also run in families.
So, if you have Depression and your sister has it,
and she's doing well on a certain medication,
there's a good chance that that drug
could be a good choice for you.
And this could be a helpful starting point for your doctor
in choosing a medication.
There's so many options for medications out there,
but having a relative do well on one
is a good place for you to start,
and a good reason to choose that one for yourself.
If this is your first video with me,
check out my other videos on Bipolar Disorder and Depression
and leave me a comment, or a question if you have one.
Or, just to say hi.
I like Hi's.
See you next time.
("My Harlem Days" by Jan Chmelar)
♪ I am what I am today 'cause I did it my way ♪
♪ Nothin' y'all can say ♪
♪ In this life or the next one ♪