Cognitive Behavioral Therapy (CBT) is an evidence-based, time-limited treatment widely used for depression and anxiety disorders. It was developed by Aaron T. Beck in the late 1900s. He discovered that his clients tended to dream about situations where they were incompetent or ineffective rather than dreaming about repressed rage as Freud would have predicted. This led Beck to develop a new cognitive model of mood disorders. He discovered in his studies that there are strong connections between mood, cognition (that is, thoughts and beliefs), and behaviour. Many studies document the effectiveness of CBT for treating mood and anxiety disorders.