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.
Two of these neurotransmitters, norepinephrine and seratonin , are not produced in sufficient quantities in a depressed person's brain. Because of this, too few messages are transmitted between neurons, and the symptoms of depression occur. In clinical depression, the chemicals in the brain are just out of balance . Any person can have occasional sadness, tiredness, or sleep problems. What counts as clinical depression is that you or a loved one has symptoms nearly everyday, all day, for at least two weeks .