Depression seems to have several roots, which may come in different proportions in different people. Many people with major depression have a genetic predisposition to it.  It tends to run in families.  There are psychological components, often beginning in childhood and family experiences which may cause thought patterns that increase the likelihood of depression.  Then current stresses which may act as triggers, or serve to worsen the symptoms.

These are the roots. There then comes a time when a tipping point is reached and some deeply biochemical changes start to take place.  Levels of certain brain chemicals (norepinephrine, serotonin, dopamine) can drop.  Levels of growth factors in the brain (BDNF) drop, and consequently certain key parts of the brain can actually shrink.  Despite what many of us learned in school, there is a key area of the brain known as the hippocampus. This is where new brain cells are being born and old ones are dying.  With low levels of BDNF the birth rate goes down and this part of the brain shrinks, leading to problems with concentration and memory.

There is an entire system of controlling and managing genes known as epigenetics.  In depressed people, this can actually cause chemical changes in the DNA itself. Some of these changes are irreversible. This explains why often depression is a chronic disease, and why, when people respond to medication and then wean themselves off, the depression more often than not comes back.

We can see on brain scans entire regions of the brain becoming less active.  Connections and networks of brain cells become more subdued.  Even the utilization of glucose and oxygen by the brain decreases.

One of the main results of this is that people’s motivation drops dramatically.  Motivation requires dopamine, one of the brain chemicals that is produced less in the depressed brain.  Just when people would need higher levels of motivation to pull themselves out of the depression, they find themselves with less.  From the outside it looks like people are healthy, and ought to be able to get themselves off the couch, out of the house, back to work, back to socializing.  On the inside, sometimes something as simple as getting up and brushing your teeth can feel like climbing Mount Everest.

Unfortunately, depression causes certain behavioral changes that only result in making the depression worse; in other words a vicious cycle. Low energy and motivation result in less exercise, and avoiding activities that might provide some pleasure. Sleep is often poor. Appetite can go up (often for junk food), causing lethargy and weight gain. Or it can go down, causing poor nutrition. People socialize less and deprive themselves of the support of others. All of the above, plus concentration and memory problems,  may make it hard to work, or even get to work; and this can bring on a whole host of other stresses.

Stigma and embarrassment can lead the depressed person to suffer in silence and to not seek the help that might well otherwise get them out of this trap. 

I use the word “trap” very deliberately. While it may superficially look like depressed people can “choose” happiness, nothing could be farther from the truth. Regardless of the factors that got it going, it becomes very biological and its symptoms make it even harder to pull up out of it by yourself

TMS Consultation Form