Cognitive-behavioral therapy
In the 1950s and 1960s, American psychiatrist Aaron T. Beck developed a cognitive model of mental illness, which would later become a part of CBT.  This cognitive model says that people feel bad because of the way they think about an event, not the actual event itself.  While doing psychoanalysis, Beck noticed that his depressed patients had a lot of negative thoughts about themselves, he world, and the future.  They seemed like they were ‘talking’ to themselves in their thoughts.  However, they only shared some of these thoughts with Beck.  For example, a person might have thought to themselves, “The therapist is being very quiet today; I wonder if he’s mad at me?” and then began to feel anxious as a result.