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When patients with anxiety and depression come to the clinic we offer
two very good treatments for them. One is a medication called selective serotonin
reuptake inhibitors called SSRIs another is cognitive behavioral therapy a kind
of talk therapy. The issue is that both of these take a long time to work so
patients have to wait three to six months before they actually see whether
they are getting an effect reducing their depression anxiety
symptoms from the treatment. The dilemma that we have for patients and for
clinicians is that we don't have any way to guide a patient to one treatment
versus another. This is important because both treatments are effective but
they're equally effective and one is very time intensive and limited in other
words CBT is not available at all clinics and SSRIs can come with adverse
side effects. So, if we could solve this mystery it'll be very important for
resource allocation but also for patients time. EEG is a method of
measuring brain waves or electrical activity right on the scalp. So a patient
can wear it as a cap right in the outpatient clinic. It's very inexpensive,
it doesn't take a lot of resources and can be located right in the office
setting. The idea is to use neuroscience based technologies to see whether we can
identify markers that we can use to predict a patient's response to one
treatment versus the other treatment. In this study we were interested in the
error-related negativity or the ERN. In this task participants see a string of
arrows and they're asked to indicate which direction the center arrow is
pointing. Is it pointing to the left or is it pointing to the right and they use a
mouse on the computer to indicate that direction. On some of the trials all of
the arrows are congruent, they're all facing the same
direction, but there's others that are more difficult where the arrows are
incongruent and that is to make it a bit more difficult. The task also provides
feedback along the way. It says try it to go faster, try to be more accurate and
this is a way for to speed participants up or to get them questioning their
performance, which inherently causes errors and we can measure the response
in the brain when they make that error. We found that a more enhanced ERN, are more
exaggerated neural response to making that mistake, was associated with better
outcomes in the talk therapy. This is the task that we use to capture reward
responding. The task essentially involves seeing two doors and guessing which door
has a prize behind it. The participants can either win or lose money and they
receive feedback after they guess. The brain component that we were interested in
tends to be enhanced after those green arrows, so whenever the
participant wins money, the brain response becomes enhanced. The more that
the reward positivity was blunted at baseline the better the participant did
with SSRIs. As the reward positivity increased, depressive symptoms went down
with both treatments, and so what we think is that this reward measure at the
brain level can help track symptom improvement for depression. One of the
problems that we have in the clinic these days is that when a patient gets a
treatment and they get side-effects or they don't feel better, they tend to drop
out of treatments. So, that ends up being a missed opportunity. Essentially we lose
the opportunity to take care of a patient and patients ultimately continue
to endure with the symptoms of anxiety and depression. What these two studies
have highlighted or discovered is that we can use a relatively inexpensive,
outpatient procedure to help come up with a way to biologically and
objectively guide a patient to the right treatment at the right time.