What Depression Looks Like in the Brain:  Stuck in Default Mode (and How to Break Out of It)

Even though depression is usually referred to as a chemical imbalance, it is actually an imbalance in networks of interconnecting regions of the brain. Specifically, sophisticated new brain imaging studies reveal that depression shows up in the brain as being stuck in “Default Mode.”  This is a looping network deep in the middle portion of the brain that, in depression, is more active than the other major networks.  The Default Mode (DMN) has strong connections to the emotional, anxiety, and fear centers of the brain, and parts of the brain that reflect thoughts about self, the past and the future.  It is also involved in thinking about the intentions behind others’ behavior.  So, a disproportionately active DMN results in a hyper-connection to the depression, anxiety, and fear centers of the brain, causes people to be sensitized about how they’re feeling, and whether other people are acting with bad intentions towards them or thinking that they’ve disappointed others.

Also, when the DMN is disproportionately active, the other important networks can’t function normally.  One of these other networks is called the Executive Network. The Executive Network is also sometimes termed the “Task Positive” Network because it is activated when we need to effectively interact with the outside world to get things done or look at things rationally.  It is more on the outer, more advanced part of the brain, rather than buried deep like the DMN, and involves important areas of the Frontal Lobes (by the way, the EN is impaired in ADHD, but that’s for another blog!). In contrast, the DMN is often referred to as the “Task Negative” network because it involves an internally-oriented focus.  This overactive Default Mode Network causes you to literally and figuratively “be in your own head.”

Importantly, with depression, not only is the DMN overactive, it also cannot be deactivated when the brain is trying to activate the Executive Network. Deactivating the DMN is essential to allow the Executive Network to work effectively and not be straining against or clashing with the DMN, again because the EN is Task Positive and the DMN is Task Negative. This is why, in addition to depressed mood, lack of enjoyment, and pessimism, people with depression also have trouble concentrating and getting things done – it is because of an overactive DMN that cannot be deactivated.

So, the DMN causes negative emotions and thoughts and prevents clearheaded thinking and productivity.  In addition, recent evidence reveals connections between this network and the brainstem that controls things like sleep, appetite, sex drive and a sense of physical sluggishness.  So, we can see how a disproportionately active DMN can contribute to all three domains of clinical depression – 1) mood and self-attitude, 2) concentration and productivity, and 3) physical symptoms like lack of energy and changes in sleep and appetite.  One can see why depression causes everything to feel so effortful.

The most effective way to treat depression, and rebalance the brain networks, is through therapy and the targeted, judicious use of medication.  So, break out of Default Mode and start the path towards feeling better!

If you are battling with depression, contact Dr. Neal Ranen to set up an appointment today!

This article was originally posted on DrNealRanenBaltimorePsychiatrist.com