One in 10 Americans has clinical depression . This is more than having a bad day or mood changes. It's a persistent loss of interest and energy that drags down a person's life and the lives of those around them. Unfortunately, two-thirds of those with depression do not even get diagnosed or treated. There's no one cause for depression.
Some people have situational depression .
This often comes after a loss or a personal tragedy. Another type is clinical depression , which is due to a long-lasting imbalance of chemicals in the brain . A look at what causes the symptoms of depression. Your brain is made up of a complex network of neurons and brain chemicals called neurotransmitters . Neurotransmitters carry messages from one neuron to another.