Systematic desensitization

# Overview
Systematic desensitization is a type of behavioral therapy used in the field of psychology to help effectively overcome phobias and other anxiety disorders.  More specifically, it is a type of Pavlovian therapy developed by a South African psychiatrist, Joseph Wolpe.  To begin the process of systematic desensitization, one must first be taught relaxation skills in order to control fear and anxiety responses to specific phobias. Once the individual has been taught these skills, he or she must use them to react towards and overcome situations in an established hierarchy of fears. The goal of this process is that an individual will learn to cope and overcome the fear in each step of the hierarchy, which will lead to overcoming the last step of the fear in the hierarchy. Systematic desensitization is sometimes called graduated exposure therapy.

# Clinical Procedure
Specific phobias are one class of mental illness often treated through the cognitive-behavioral process of systematic desensitization. When individuals possess irrational fears of an object, such as height, dogs, snakes, and close spaces, they tend to avoid it. Since escaping from the phobic object reduces their anxiety, patients behavior to reduce fear is reinforced through negative reinforcement, a concept defined in operant conditioning. The goal of SD is to overcome this avoidance pattern by gradually exposing patients to the phobic object until it can be tolerated. This will be challenging for the patient at first to deal with the fear, but gradually, most will overcome this fear. In classical and operant conditioning terms the elicitation of the fear response is extinguished to the stimulus (or class of stimuli).

## Coping Strategies
Prior to exposure, the therapist teaches the patient cognitive strategies to cope with anxiety. This is necessary because it provides the patient with a means of controlling their fear, rather than letting it build until it becomes unbearable. Relaxation training, such as meditation, is one type of coping strategy. Patients who have serious anxiety that leads to breathing problems, might be taught to focus on their breathing or to think about happy situations. Another means of relaxation is cognitive reappraisal of imagined outcomes. The therapist might encourage subjects to examine what they imagine happening when exposed to the phobic object, allowing them to recognize their catastrophic visions and contrast them with the actual outcome. For example, a patient with a snake phobia might realize that they imagine any snake they encounter would coil itself around their neck and strangle them, when this would not actually occur. These patients need to see that not all snakes are large and that most snakes are completely harmless so that they can get over their fear. Research at the University of Pennsylvania has demonstrated the effectiveness of this technique in helping subjects reduce similar animal phobias.

## Progressive Exposure
The second component of systematic desensitization is gradual exposure to the feared objects. Continuing with the snake example, the therapist would begin by asking their patient to develop a fear hierarchy, listing the relative unpleasantness of various types of exposure. For example, seeing a picture of a snake in a newspaper might be rated 5 of 100, while having several live snakes crawling on ones neck would be the most fearful experience possible. Once the patient had practiced their relaxation technique, the therapist would then present them with the photograph, and help them calm down. They would then present increasingly unpleasant situations: a poster of a snake, a small snake in a box in the other room, a snake in a clear box in view, touching the snake, etc. At each step in the progression, the patient is desensitized to the phobia through the use of the coping technique.  They realize that nothing bad happens to them, and the fear gradually extinguishes.