A depressed vs. normal brain

Depression is a mood disorder that impacts the way we feel, think, and behave. People who struggle with depression experience the symptoms such as persistent feelings of sadness and hopelessness, weight change, sleep problems, feelings of guilt and worthlessness, difficulty in thinking, concentrating, and making decisions, fatigue, restlessness, etc.

However, PET scans show that depression affects the brain. By comparing brain activity during periods of depression with regular brain activity, PET scans show decreased brain activity due to depression. The scientific findings suggest that three parts of the brain may play a role in depression: the amygdala, the hippocampus, and the prefrontal cortex.

The subtle but significant differences between a healthy brain and a depressed brain involve brain shrinkage, grey matter abnormalities, and increased amygdala activity in depressed brains.

How Does Depression Physically Affect the Brain?

Here are the key differences between a normal brain versus a depressed brain.

Brain Shrinkage

Research shows that depression can cause the shrinkage of specific brain regions. According to scientists, people with depression release larger amounts of cortisol, the stress hormone in the brain, than those who don't experience depression. Our bodies release cortisol during times of mental and physical stress, which is typical for depression.

In a normal brain, neurons (brain cells) are continually produced in the hippocampus. However, increased cortisol levels over the long-term can slow the production of neurons and cause the hippocampus to shrink, which usually leads to problems with memory.

Similarly, the prefrontal cortex is responsible for regulating emotions, creating memories, and making decisions. The prefrontal cortex appears to shrink as a result of constant exposure to high levels of cortisol.

Grey Matter Abnormalities

Grey matter is a brain tissue that contains cell bodies and nerve cells. The gray matter in the brain involves the regions responsible for memory, emotions, sensory perception, muscle control, self-control, and decision making.

Research shows that people who experience depression appear to have a thicker gray matter in parts of the brain involved in emotions and self-perception.

An Increased Activity of the Amygdala

The amygdala is a cluster of cells near the base of the brain that regulates our emotional responses. Because of constant exposure to high levels of cortisol, the amygdala becomes enlarged and more active in people with depression.

On the other hand, MRI scans show that after practicing mindfulness, the grey matter in the amygdala can shrink, reducing its activity. At the same time, the gray matter in the prefrontal cortex (the brain's area responsible for emotional control, problem-solving, and planning) becomes thicker.

Can Depression Treatment Alter the Brain?

Balancing the amount of cortisol in the brain can help reverse the hippocampus's shrinkage and reduce the symptoms of depression.

The most common medication treatment options for depression help balance the chemicals in the brain. These include medications such as selective serotonin uptake inhibitors, norepinephrine-dopamine reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, monoamine oxidase inhibitors, and atypical antidepressants.

In addition to medication, it is believed that psychotherapy can alter brain structure and alleviate depression symptoms. Also, a healthy lifestyle such as staying active, practicing relaxation, eating nutritious food, sleeping well, and avoiding alcohol and drugs can boost brain health and help relieve depression symptoms.