As with all other mental conditions, Depression is a brain disorder. Cognitive Behavior Therapy (CBT) actually has been shown to change brain chemistry.
The first studies to prove how effective Cognitive Behavior Therapy (CBT) was – done in the 1980’s – were conducted with people who were clinically Depressed.
Some people recover from Depression with CBT alone, without use of meds. Some prefer to use both CBT and medication. Either way, if you think you feel depressed, it’s treatable.