The brain is the most complex structure known to mankind and sometimes, it can get tired and cause depression. What happens inside a depressed brain? Read on to find out.
Author: Belinda Lin
Editors: Vincent Chang and Peggy Yang
Artist: Kimberly Arinton
You’ve probably heard of the famous author Ernest Hemingway. He is known for his confident personality. But in 1961, he committed suicide from a lifelong battle against depression and alcoholism. Like Hemingway, 264 million others suffer from depression globally. Depression is where someone constantly feels withdrawn or tired. These symptoms can alter within a matter of days. It’s almost bizarre to think that one day someone is fine, but the next, their whole attitude changes. How does the brain play a role in depression?
PET scans reveal that brain energy rises during manic episodes and falls during depressive episodes. Our limbic system is responsible for depressive moods. It includes the hippocampus, which correlates without memory; the thalamus, which regulates our senses; and the amygdala, which regulates our emotions and stress. The amygdala enlarges when our depressive states come in, which can activate sleep disturbances, changes in activity levels and other hormones, and cause brain inflammation.
Biological factors are not the only ones that affect our depressive moods; the way we think psychologically also affects our brain and moods.
There are three ways in which depressive episodes can arise: biological, psychological, and social-cultural influences. Biological influences are genetic predispositions. High stress levels can also cause changes in brain chemistry. Psychological influences include having a negative explanatory style, which arises from pessimism. For example, when you go through a breakup, you either have a positive way of thinking: I will get over this, or you have a negative way of thinking: I will never get over this. Having a negative explanatory style can lead to learned helplessness, which leads to self-deprecating beliefs, beliefs where you are putting yourself down. Social-cultural influences include traumatic experiences, cultural expectations, or depression-evoked responses. PTSD can also trigger depression in many people.
Many times, depression can lead to other disorders like alcoholism, like it was with Ernest Hemingway—anxiety, fatigue, anorexia, bulimia, and insomnia. Many patients with depression seek therapy sessions to regulate moods, take medications like antidepressants, and avoid alcohol.
“Depression (Major Depressive Disorder).” Mayo Clinic, Mayo Foundation for Medical
Education and Research, 3 Feb. 2018,
“Depression.” World Health Organization, World Health Organization,
Higuera, Valencia. “Everything You Want to Know About Depression.” Healthline, Healthline
Media, 11 Feb. 2020,