Today, I’m continuing the topic of Monday’s post:  depression.  Patients with pain often have symptoms of depression.  You have to cope with the pain itself, but also all the negative consequences of having a pain disorder, and these stresses can cause depression to creep in.  Many patients think, “Oh, I should be able to cope with this,” and may even hear this from their family also.

What I tell patients, however, is that significant depression, medical depression, is a medical disorder.  Just the same as asthma is a lung disorder or an ulcer is a stomach disorder.  Depression is just a brain disorder.  And here’s some proof:

One central symptom of depression is what we call “anhedonia,” which is the loss of interest in doing things you used to like to do, and when you do these enjoyable activities, you don’t get much enjoyment out of them.  But how does this translate to brain science??

Jane Epstein and other brain imaging researchers at Cornell looked at the brains of people with depression using fMRI (fMRI is a “functional” MRI, which looks at what parts of people’s brains are active when they do different functions or tasks).  Here’s what they found:

• The brains of patients with depression respond less to positive words.  There was less activity in a part of the brain called the ventral striatum in patients with depression than those without depression, when they were reading positive words.
• Those patients who had the most anhedonia had the lowest level of activity in this particular brain region, showing a correlation.

This type of work is exciting because it show the brain regions where psychological processes are happening.  And I think this helps people who are suffering from depression think about their problem as a medical illness rather than some character flaw or weakness.  That, at least, is my hope.

(The full study can be found in the American Journal of Psychiatry, 2006, 163, 1784-1790.)