Cognitive theory states that maladaptive behavior is associated with patterns of thinking and response that do not result in mentally healthy outcomes. The goal of cognitive-behavioral therapy (CBT) is to change or substitute these patterns with more realistic and useful thoughts and responses. CBT is used to treat depression, anxiety disorders, phobias, and other forms of mental disorders. Medication is often used in conjunction with this approach to treat mood disorders and more severe forms of mental disorders.

Schools of psychotherapy associated with this discipline are rational emotive therapy, rational behavior therapy, rational living therapy, cognitive therapy, and dialectic behavior therapy.

John Watson is considered the father of behavioral therapy. Ivan Pavlov investigated classical conditioning. Joseph Wolpe developed the process of systematic desensitization. Jean Piaget identified four stages of cognitive development. Albert Ellis developed rational emotive behavior therapy in the 1950s, followed by Aaron Beck with his cognitive therapy in the 1960s. Donald Meichenbaum combined components of cognitive theory with behavioral theory and termed cognitive-behavioral therapy. Gerald Patterson, Robert Liberman, and Richard Stuart were leaders in behavioral family therapy.