major depressive disorder which is
sometimes just referred to as depression
is characterized by prolonged
helplessness and discouragement about
the future individuals with this
disorder have low self-esteem and very
powerful feelings of worthlessness they
also lack the energy to do the things
that they used to enjoy much less the
things that they have to do or the
things that they don't enjoy they tend
to feel socially isolated and have
trouble focusing on important tasks and
have trouble making decisions and this
low mood tends to pervade all aspects of
their life there are a number of
physical symptoms that also go along
with depression lethargy so feeling
fatigued individuals with depression
also tend to show fluctuations in weight
so either a lot of weight gain or a lot
of weight loss and they might also have
trouble sleeping where they might sleep
too much and I think that these physical
symptoms are often ignored because in
Western cultures like in the US we tend
to think about depression in terms of
moods or in terms of emotional states
but for individuals in some Eastern
cultures especially cultures where it
might be seen as inappropriate to delve
into or talk about feelings and emotions
people in these cultures tend to think
about depression and experience
depression in terms of these bodily
symptoms and so it's really important
that these aren't discounted depression
or depressive symptoms are the number
one reason people seek out mental health
services and because of this some people
have taken to calling it the common cold
of psychological disorders and I like
that term for some reasons and I dislike
it for others what I like about it is
that it captures how pervasive this
disorder is it is estimated that 13% of
men and 22% of women worldwide could
meet the criteria for depression at
least once in their lives and one study
has shown that as high as 31 percent of
college students might experience this
disorder and these are really high
numbers
and so in that way I think that this
term is appropriate however I think that
the term common cold doesn't really
capture the seriousness of this disorder
because depression isn't just feeling
down once in a while and it's not
feeling sadness or grief at appropriate
times which is just a normal part of
life and I think that this term kind of
minimizes that part of the disorder
depression can be triggered by a life
event like a loss or breakup but it
doesn't have to be
it also doesn't usually appear alone
it is actually really common for
individuals with depression to have
other disorders such as anxiety
disorders and I've been writing in this
blue color at a kind of signify
depression but I'm kind of getting bored
with it now so let me switch it up so
there are a number of factors that may
be involved in depression and I'm going
to split them up into three categories
biological factors psychological factors
and socio-cultural or environmental
factors and let me let me take a minute
to get all of that down all right first
of all we know from family and twin
studies that there's a genetic component
to depression and we also know from
studies that use functional imaging that
individuals with depressions show a
decreased activation in the prefrontal
cortex and this could be associated with
the problems with decision-making that
people with depression tend to have as
well as their difficulties and
generating actions researchers have also
found lower levels of activity in the
reward circuitry in the brain and this
could help to explain why individuals
with depression might not find enjoyment
in the actions that they once found
pleasurable depression has also been
associated with certain
neurotransmitters and neurotransmitter
regulation and I'll abbreviate that here
by writing NT for neurotransmitter
research has suggested that individuals
with depression might have fewer
receptors for serotonin and
norepinephrine and I think that all of
this research is amazing I think that
it's really
important and it's also really
compelling in a way that research
findings that include neuroscience
typically are but with that said I
really want to caution you against
oversimplifying these biological factors
to give an example about why I'm saying
this I want to talk about the
relationship between a certain serotonin
transporter gene and depression and this
gene is known as 5-htt LPR and I'll
write that down and a lot of findings
have shown that this gene is involved in
depression but in actuality it is only
associated with depression if the
individual with the gene is in a
stressful environment but the story
doesn't actually end there it's actually
even more complicated because it turns
out that if an individual with this
genetic feature is placed in a warm and
positive environment they actually show
a decreased risk for depression and this
is something that we don't totally
understand yet we're still trying to
figure out why this might be the case
but importantly I think that this really
shows us how complicated biological
factors can be let's move on to some
psychological factors that might
influence depression one theory is based
on the concept of learned helplessness
and this theory supposes that if an
individual is exposed to aversive
situations over and over again without
any power to change or control them they
might begin to feel powerless in a way
that might lead to depression so if
someone is exposed to prolonged stress
due to family life or bullying or some
other cause that they don't have control
over their helplessness could spiral out
of control and they might stop trying to
change their situation because they
perceive it to be completely helpless
and that's a behavioral theory or way of
thinking about depression but there are
cognitive theories about it as well and
these theories tend to focus on thoughts
or beliefs that with repetition could
trigger depression and while it's true
that everyone has negative or self
two thoughts every once in a while
generally we are able to step back from
them and we're able to realize that what
we're thinking isn't completely logical
but sometimes people can get trapped in
these thought patterns and they might
put too much emphasis on negative
thoughts and actions and experiences and
when they ruminate on these things when
they turn them over and over in their
minds it's possible that these cognitive
distortions might lead to depression
another cognitive theory about
depression focuses on the concept of
attribution or explanatory style now as
we go about our daily lives we naturally
try to understand and explain the events
that go on around us and when we do this
we can either attribute the things we
see to internal or external causes so is
it something that I did or is it
something that happened because of
something that is completely out of my
control did I get a bad grade on a test
because I didn't study that would be an
internal cause or did I get a bad grade
because the teacher made a really unfair
test which would be an external cause
individuals with depression tend to
attribute negative experiences to
internal causes so maybe they'll think
that a friend didn't call or text back
because they are unlikable or unlovable
and not because they were at the movies
with their family and maybe their phone
was off in addition to this they tend to
see negative experiences as being stable
so they think that they'll continue to
happen in the future and I also tend to
think that they're global so they might
assume that one friend not calling them
back somehow signifies that none of
their friends like them and together
these things these internal attributions
these stable attributions and global
attributions these things form a
pessimistic attributional style and it
might make certain individuals
particularly vulnerable to depression
and there are many other psychological
theories about depression things that
have to do with coping style or
self-esteem but it can actually be hard
to know whether these things cause
depression or if they are the result of
it
so does a pessimistic attributional
style lead to depression or do people
with depression tend to have a
pessimistic attributional style it isn't
always clear environmental and
socio-cultural factors can also have a
strong influence on depression having a
friend or partner or roommate with
depression can actually increase the
likelihood that individuals around them
will also develop depression and
although we don't know exactly why that
is some researchers suggest that it
might have to do with Co rumination
where friends talk about problems and
negative events but instead of
discussing how to solve them they focus
on the negative emotions and dwell on
future problems and occurrences and on
some level this is kind of normal it is
perfectly normal for close friends to
take on some of the negative feelings of
the other like being sad when they lose
someone who was close to them were being
angry if they were dumped by their
partner this is just natural empathy but
the same empathy that allows us to
comfort our friends when they're in
distress might also be the reason that
depression seems to spread we also know
that individuals with a low
socioeconomic status especially those
living in poverty are more likely to
develop depression as are those who are
struggling to keep a job or have just
lost a job and there are other
environmental factors as well social
isolation child abuse even prejudice
have all been implicated in causing
depression and let's think about this in
terms of prejudice if someone grows up
in a household that has negative
feelings about homosexuality and if they
grow up and begin to have same-sex
attractions they've probably internalize
the prejudice after years of hearing it
and this could lead to depression
alright so stepping back for a second we
said that we had biological factors
psychological factors and socio-cultural
and in varna
until factors and when we put all of
these things together we get what is
referred to as a biopsychosocial model
of depression and this theory
acknowledges that all of these factors
play a role so some people are
genetically predisposed to the condition
but it only comes about if the situation
is right or if we develop certain
patterns of thinking