How Does Depression Affect the Brain?
There are three parts of the brain that appear to play a role in MDD: the hippocampus, amygdala, and prefrontal cortex.
The hippocampus is located near the center of the brain. It stores memories and regulates the production of a hormone called cortisol. The body releases cortisol during times of physical and mental stress, including during times of depression. Problems can occur when excessive amounts of cortisol are sent to the brain due to a stressful event or a chemical imbalance in the body. In a healthy brain, brain cells (neurons) are produced throughout a person’s adult life in a part of the hippocampus called the dentate gyrus. In people with MDD, however, the long-term exposure to increased cortisol levels can slow the production of new neurons and cause the neurons in the hippocampus to shrink. This can lead to memory problems.
The prefrontal cortex is located in the very front of the brain. It is responsible for regulating emotions, making decisions, and forming memories. When the body produces an excess amount of cortisol, the prefrontal cortex also appears to shrink.
The amygdala is the part of the brain that facilitates emotional responses, such as pleasure and fear. In people with MDD, the amygdala becomes enlarged and more active as a result of constant exposure to high levels of cortisol. An enlarged and hyperactive amygdala, along with abnormal activity in other parts of the brain, can result in disturbances in sleep and activity patterns. It can also cause the body to release irregular amounts of hormones and other chemicals in the body, leading to further complications.
Many researchers believe high cortisol levels play the biggest role in changing the physical structure and chemical activities of the brain, triggering the onset of MDD. Normally, cortisol levels are highest in the morning and decrease at night. In people with MDD, however, cortisol levels are always elevated, even at night.
How Can Treatment Change the Brain?
Experts have found that balancing the amount of cortisol and other chemicals in the brain can help reverse any shrinkage of the hippocampus and treat the memory problems it may cause. Correcting the body’s chemical levels can also help reduce symptoms of MDD.
There are several common medications that can fight the negative effects of depression on the brain by helping to balance the chemicals in the brain. These include:
- selective serotonin uptake inhibitors (SSRIs): These drugs can help alleviate symptoms of MDD by changing the levels of a chemical called serotonin in the brain. Examples of SSRIs include fluoxetine (Prozac), paroxetine (Paxil), and citalopram (Celexa).
- serotonin-norepinephrine reuptake inhibitors (SNRIs) and tricyclic antidepressants: When used together, these medications can relieve MDD symptoms by altering the amounts of serotonin and norepinephrine in the brain. These chemicals help boost mood and energy levels. Examples of SNRIs include duloxetine (Cymbalta) and venlafaxine (Effexor XR). Imipramine (Tofranil), nortriptyline (Pamelor), and trimipramine (Surmontil) are examples of tricyclic antidepressants.
- norepinephrine-dopamine reuptake inhibitors (NDRIs): These medications aid people with MDD by increasing levels of the mood-boosting chemicals norepinephrine and dopamine in the brain. Bupropion (Wellbutrin) is a type of NDRI that may be used.
- monoamine oxidase inhibitors (MAOIs): These drugs help ease symptoms of MDD by increasing the amount of norepinephrine, serotonin, and dopamine in the brain. They can also improve brain cell communication
- atypical antidepressants: This group of medications includes tranquilizers, mood stabilizers, and antipsychotics. These drugs can block brain cell communication in order to relax the body.
Besides medications, certain medical procedures can also affect the brain to help ease symptoms of MDD. These include:
- electroconvulsive therapy (ECT), which involves passing electrical currents through the brain to boost communication between brain cells
- transcranial magnetic stimulation (TMS), which involves sending electrical pulses into the brain cells that regulate mood
Researchers also believe that psychotherapy can alter brain structure and help relieve MDD symptoms. Specifically, psychotherapy appears to strengthen the prefrontal cortex.
There are other ways to boost brain health and help recover from MDD without medical intervention. These include:
- eating healthful foods and staying active, which stimulates brain cells and strengthens communication between brain cells
- sleeping well, which helps grow and repair brain cells
- avoiding alcohol and illegal drugs, which can destroy brain cells
Talk to your doctor about which treatments may be best for you.
Having depression can lead to a reduced quality of life, and could even
contribute to health problems such as weight gain. But now, new research
indicates another important concern. A new study from the University of Miami
has discovered a correlation between depression and increased risk of stroke.
A
long-term (fourteen-year) study found that older adults who suffered from
depression at the beginning of the study period were 75 percent more likely to
experience an ischemic stroke. An ischemic stroke is one of the two main types
of stroke (hemorrhagic is the other). With an ischemic stroke, a blood flow
blockage results in damage to the brain.
The study’s author was
careful to clarify that this correlation does not necessarily indicate that
depression causes stroke. But since the
two are highly related, it’s an area of study that warrants more investigation.
Depression
is common in retirees, for many reasons. Sometimes, the end of a career leads
to emptiness or boredom. Loneliness can play a part as well; the absence of a
work routine, or the illness of a spouse, can contribute to isolation.
Whether
or not depression actually causes strokes, or they’re merely related in some
other way, taking care of your mental health is essential. As you transition
into retirement, remember to have a plan for your days; simply stopping work
isn’t usually as enjoyable as people had imagined! Create some structure in
your life, plan for activities outside the home, and include some social time
with friends or family.
In addition, the following tips can prevent depression:
- Exercise regularly
- Eat a well-balanced, nutritious diet, avoiding excess sugar
- Identify sources of stress and create strategies to address it
- Get regular, quality sleep each night
- Avoid alcohol and drugs
- Report symptoms of depression to your doctor – sometimes depression is a side effect of certain medications
And of course, remember to seek help if you ever feel that you need it. Trained mental health professionals can help you identify the source(s) of your feelings, and guide you toward developing solutions.
