The depressed brain

October 3rd, 2023

Torben Bergland, MD

A depressed brain may look like any other brain, but it functions differently. We are all surrounded by positive and negative things. In depression, the brain gets stuck on what is negative. The depressed brain has a negative bias that affects how it functions.

  • Its attention is on what is negative rather than what is positive.

  • It perceives things to be more negative than they actually are.

  • It tends to interpret neutral and even positive things negatively.

  • It's more sensitive to physical and emotional pain and senses less pleasure from positive things.

  • It expects negative things to happen.

  • Its recollection is biased toward negative memories and may distort what was positive.

The depressed brain is essentially hypersensitive to whatever is negative and misses out on what is positive. Because of this negative bias, depression often becomes a downward spiral of negativity.

Beyond these functional changes, there are also physical changes in the depressed brain. The 86 billion nerve cells in the brain communicate by chemical messengers, neurotransmitters, in trillions of nerve connections called synapses. In depression, we may see decreased activity in neurotransmitter systems, like those of serotonin, noradrenaline, dopamine, and others.

But depression is far more complex than simply a chemical imbalance or deficiency. The connection and communication between parts of the brain may be disrupted and changed, particularly between the thinking part of the brain, the frontal lobe, and the feeling part of the brain, the limbic system. Some parts of the brain may become hyperactive, while others are less active. Some parts of the brain may even physically shrink.

The immune system may also be involved in depression. Stress, trauma, physical illness, and a harmful lifestyle may trigger inflammation that may be toxic to the brain cells. 

Depression is, therefore, the result of changes in the complex systems and interactions of neurotransmitters, nerve cells, brain structures, and the rest of the body. Depression is actually also a physical illness.

There is hope for the many who suffer from depression. Depression can be overcome.

In the next article, we’ll explore effective self-care strategies for depression. is a project of Adventist Health Ministries.

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