- [Instructor] Dissociative
Identity Disorder,
which was formerly called
Multiple Personality Disorder,
describes cases where two or
more distinct personalities
or distinct identities seem
to exist within a single body.
And both of these identities
have some kind of influence
on that person's thoughts or behaviors.
These identities are
distinct from one another.
They have their own mannerisms.
They can have different
emotional responses.
And there can sometimes
even be physical changes,
and I'm going to put
physical in quotes here,
because I don't actually
mean that there are changes
in body parts in any way, but
there have been some cases
where researchers have described
that the distinct identities
have different handedness.
One identified as being left handed,
and the other identified
as being right handed.
There are also cases where
one of the personalities,
typically the original personality,
denies the existence of the other ones.
So, it isn't actually aware
that these other distinct
personalities exist
within that person.
So how would something
like this come about?
Research indicates that
individuals who've been diagnosed
with Dissociative Identity
Disorder have a history
of child abuse,
or some other kind of
extreme life stressor.
And there are a lot of different theories
as to how this could happen,
but they all seem to
center on a central idea,
which is that under
cases of extreme stress,
a person's conscious
awareness disassociates,
or separates from,
certain painful memories,
or thoughts, or feelings.
How common is Dissociative
Identity Disorder?
How often do we see it in the population?
And the answer is,
Dissociative Identity Disorder
is extremely rare.
In fact, I think that
one of the only reasons
that people are aware of this disorder is
because it winds up in movies or books
as a plot point or a plot twist.
And we also know about it
because we sometimes hear
about it in the news.
And by that, I mean that it's
been popularized by extreme
and sometimes fake cases.
If you have some time,
you can look up the case
of Kenneth Bianchi, who was
known as the Hillside Strangler.
He was a man who claimed
that his crimes were actually
the result of a different personality.
It was later determined
that this was not the case.
However, it did put this
disorder in the news.
Unlike the other disorders
that we've talked about so far,
there's actually a fair
amount of controversy
that surrounds this one.
And part of that controversy
has to do with how rare it is.
Because as rare as it is in North America,
in the United States, it's even more rare
outside of America.
This leads some scientists to wonder
whether or not it's some
kind of cultural construct
instead of a real disorder.
Others wonder if this is a disorder
than can be induced by therapists.
So, maybe a therapist who
knows about this disorder,
and suspects that someone might have it,
might say things like,
"Do you ever feel like there
is another part of you?
"Maybe a part of you that
you aren't always aware of?"
And then from there, that
can be taken even further.
They might ask something like,
"Does this part have a name?
"Can I speak to this part?"
And in response to this, the individuals
who are seeking therapy
might intentionally
or unintentionally play along
with what the therapist is saying.
This brings up another interesting point
about personality changes
and about role-playing.
Because in some way,
we actually all have
multiple personalities.
The person who we are when
we're in private is different
from the person who we are when
we're with our grandparents
or our friends.
We all play different roles in life,
and we're expected to
play different roles.
We step up to them and we play along,
and we don't even think about it.
That's just how we act
in different situations.
So, maybe some people, in
situations of extreme stress,
might kind of lose themselves
in these different roles,
sort of the same way that an
actor might lose themselves
in a part.
So these multiple personalities,
these supposedly distinct identities,
could be some kind of
extreme form of role-playing,
maybe even one the
individual isn't aware of.
And at this time, the answer doesn't seem
to be completely clear.
