Summary
Depression is a state of low mood and aversion to activity that can affect a person’s thoughts, behavior, feelings, etc.[1][2] Depressed people can feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable or restless.
Most biological theories focus on the monoamine chemicals serotonin, norepinephrine and dopamine, which are naturally present in the brain and assist communication between nerve cells.
Starting point this wikipedia entry from April 27, 2016.
OnAir Post: Depression Overview
