Cognitive behavioral therapy is a psychotherapeutic approach that aims to teach a person new skills on how to solve problems concerning dysfunctional emotions, behaviors, and cognitions through a goal-oriented, systematic approach. This title is used in many ways to differentiate behavioral therapy, cognitive therapy, and therapy that is based on both behavioral and cognitive therapies. There is empirical evidence that shows that cognitive behavioral therapy is quite effective in treating several conditions, including personality, anxiety, mood, eating, substance abuse, and psychotic disorders. Treatment is often manualized, as specific psychological orders are treated with specific technique-driven brief, direct, and time-limited treatments.

Cognitive behavioral therapy can be used both with individuals and in groups. The techniques are often adapted for self-help sessions as well. It is up to the individual clinician or researcher on whether he/she is more cognitive oriented, more behavioral oriented, or a combination of both, as all three methods are used today. Cognitive behavioral therapy was born out of a combination of behavioral therapy and cognitive therapy. These two therapies have many differences, but found common ground on focusing on the "here and now" and on alleviating symptoms.

Evaluating cognitive behavioral therapy has led to many believing that it is more effective over psychodynamic treatments and other methods. The United Kingdom advocates the use of cognitive behavioral therapy over other methods for many mental health difficulties, including post-traumatic stress disorder, obsessive-compulsive disorder, bulimia nervosa, clinical depression, and the neurological condition chronic fatigue syndrome/myalgic encephalomyelitis. The precursors of cognitive behavioral therapy base their roots in various ancient philosophical traditions, especially Stoicism. The modern roots of CBT can be traced to the development of behavioral therapy in the 1920s, the development of cognitive therapy in the 1960s, and the subsequent merging of the two therapies. The first behavioral therapeutic approaches were published in 1924 by Mary Cover Jones, whose work dealt with the unlearning of fears in children.

The early behavioral approaches worked well with many of the neurotic disorders, but not so much with depression. Behavioral therapy was also losing in popularity Session Planning due to the "cognitive revolution." This eventually led to cognitive therapy being founded by Aaron T. Beck in the 1960s. The first form of cognitive behavioral therapy was developed by Arnold A. Lazarus during the time period of the late 1950s through the 1970s. During the 1980s and 1990s, cognitive and behavioral therapies were combined by work done by David M. Clark in the United Kingdom and David H. Barlow in the United States. Cognitive behavioral therapy includes the following systems: cognitive therapy, rational emotive behavior therapy, and multimodal therapy. One of the greatest challenges is defining exactly what a cognitive-behavioral therapy is. The particular therapeutic techniques vary within the different approaches of CBT depending upon what kind of problem issues are being dealt with, but the techniques usually center around the following:

Keeping a diary of significant events and associated feelings, thoughts, and behaviors.
Questioning and testing cognitions, evaluations, assumptions, and beliefs that might be unrealistic and unhelpful.
Gradually facing activities that may have been avoided.
Trying out new ways of behaving and reacting.

In addition, distraction techniques, mindfulness, and relaxation are also commonly used in cognitive behavioral therapy. Mood-stabilizing medications are also often combined with therapies to treat conditions like bipolar disorder. The NICE guidelines within the British NHS recognize cognitive behavioral therapy's application in treating schizophrenia in combination with medication and therapy. Cognitive behavioral therapy usually takes time for patients to effectively implement it into their lives. It usually takes concentrated effort for them to replace a dysfunctional cognitive-affective-behavioral process or habit with a more reasonable and adaptive one, even when they recognize when and where their mental processes go awry. Cognitive behavioral therapy is applied to many different situations, including the following conditions:

Anxiety disorders (obsessive-compulsive disorder, social phobia or social anxiety, generalized anxiety disorder)
Mood disorders (clinical depression, major depressive disorder, psychiatric symptoms)
Insomnia (including being more effective than the drug Zopiclone)
Severe mental disorders (schizophrenia, bipolar disorder, severe depression)
Children and adolescents (major depressive disorder, anxiety disorders, trauma and posttraumatic stress disorder symptoms)
Stuttering (to help them overcome anxiety, avoidance behaviors, and negative thoughts about themselves)

Cognitive behavioral therapy involves teaching a person new skills to overcome dysfunctional emotions, behaviors, and cognitions through a goal-oriented, systematic approach. There is empirical evidence showing that cognitive behavioral therapy is effective in treating many conditions, including obsessive-compulsive disorder, generalized anxiety disorder, major depressive disorder, schizophrenia, anxiety, and negative thoughts about oneself). With the vast amount of success shown by the use of this therapy, it is one of the most important tools that researchers and therapists have to treat mental disorders today.