Systematic desensitization is a type of exposure therapy based on the principle of classical conditioning. Wolpe developed it during the 1950s to treat phobias and anxiety disorders.
It involves gradually exposing the individual to the feared object or situation in a controlled and relaxed environment.
The process combines relaxation techniques with a hierarchical exposure to the anxiety-causing stimulus, allowing the individual to confront and reduce their fear without an anxiety response gradually.
The therapy removes the fear response to a phobia. Counter-conditioning substitutes a relaxation response for the conditioned stimulus instead.
The patient is counterconditioned, taught a new association that is to counter the original behavior learnt. The new response they learn is relaxation instead of fear (being mindful) because fear and relaxation cannot coexist (reciprocal inhibition).
A desensitization hierarchy is constructed, and the patient works through it, visualizing each anxiety-provoking event while engaging in the relaxation response.
The number of sessions required depends on the severity of the phobia. Usually, 4-6 sessions, up to 12 for a severe phobia.
The therapy is complete once the agreed therapeutic goals are met (not necessarily when the person’s fears have been completely removed).
How Desensitization Works
- In vitro – the client imagines exposure to the phobic stimulus.
- In vivo – the client is actually exposed to the phobic stimulus.
Research has found that in vivo techniques are more successful than in vitro (Menzies & Clarke, 1993). However, there may be practical reasons why in vitro may be used.
The Three-Step Systematic Desensitization Process
- Relaxation Training: The client learns deep muscle relaxation, breathing exercises and guided imagery to reach a calm state on command.
- Anxiety Hierarchy: Client and therapist rank fear-inducing situations from least to most frightening, creating the structure the therapy follows.
- Graded Exposure: Starting at the bottom, the client confronts each step while staying relaxed, moving up only once anxiety fades.
Relaxation training matters because of reciprocal inhibition: two opposite physical states cannot occur at once. Fear tenses the body; relaxation releases it. Anxiety raises heart rate, tenses muscles and quickens breathing, while deep relaxation is its physiological opposite.
As Wolpe (1969) himself put it: “if a response inhibitory of anxiety can be made to occur … it will weaken the bond between these stimuli and the anxiety.” Pairing relaxation with the feared stimulus, again and again, lets calm replace fear as the learned response.
Examples
Applying the three-step process of systematic desensitization to treating a phobia of spiders:
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Relaxation Training:
- The individual is first taught relaxation techniques, such as deep breathing, progressive muscle relaxation, or guided imagery.
- They practice these techniques until they can achieve a relaxed state consistently on command.
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Establishment of Anxiety Hierarchy:
- Together with the therapist, the individual creates a list of situations involving spiders, ranked from least anxiety-provoking to most.
- This might look like:
- Thinking about a spider.
- Looking at a picture of a spider.
- Watching a video of a spider.
- Being in the same room as a spider inside a closed container.
- Watching someone else handle a spider.
- Standing close to a spider inside an open container.
- Touching a spider with a gloved hand.
- Holding a spider with bare hands.
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Gradual Exposure:
- The client reaches a state of deep relaxation and is then asked to imagine (or is confronted by) the least threatening situation in the anxiety hierarchy.
- For example, in a relaxed state, the individual first thinks about a spider. The focus here is on maintaining relaxation despite the thought.
- Once they can think about spiders without anxiety, they move to the next level, like looking at a picture of a spider while staying relaxed.
- The process continues, with the individual gradually exposed to more direct interactions with spiders while maintaining their calm, until they can eventually handle a spider without significant fear.
Throughout the process, the goal is for the individual to associate spiders with feelings of relaxation rather than fear, eventually diminishing the phobic response.
Application
Wolpe (1964) successfully used the method to treat an 18-year-old male with a severe handwashing compulsion. The disorder involved a fear of contaminating others with urine.
After urinating, the patient felt compelled to spend 45 minutes cleaning his genitalia, two hours washing his hands, and four hours showering.
Treatment began with relaxation. Wolpe then asked the man to imagine low-anxiety scenes, such as an unknown man touching a trough of water containing one drop of urine. The exposure was entirely imagined.
As the patient’s anxiety gradually dissipated, Wolpe gradually increased the imaginary concentration of urine.
In addition, a real bottle of urine was presented at a distance and moved closer to the patient in gradual steps.
Finally, Wolpe could apply drops of diluted urine to the back of the patient’s hand without evoking anxiety. A follow-up four years later revealed complete remission of the compulsive behaviors.
A different approach came from Mary Cover-Jones. She studied several children to find the best way to remove fear responses. Her most famous case, known as Little Peter (Jones, 1924), is considered the earliest example of any kind of behavioural treatment.
She brought a caged rabbit progressively closer to Peter while he ate a favourite food. His pleasure in eating counter-conditioned his fear. This graded, food-paired approach was the direct forerunner of Wolpe’s relaxation-paired hierarchy, which he named systematic desensitization decades later.
Exposure-Based Variants: Implosion and Flooding
Implosion and flooding are faster, more intense relatives of systematic desensitization, sharing its roots in classical conditioning. Both drop the gradual hierarchy and confront the feared stimulus directly, rather than working up to it step by step.
Anxiety cannot stay at its peak forever.
Implosion
Implosion starts the client at the top of the hierarchy, not the bottom. The therapist asks them to imagine their most frightening scenario straight away, adding vivid verbal detail to intensify it, a technique called stimulus augmentation.
Nothing happens in the real world. Only the mental picture grows more vivid as the therapist keeps describing it, while the client stays seated throughout.
Two mechanisms are thought to drive the change. Held at a peak for long enough, anxiety triggers physical exhaustion, so it can only fall.
Escape is blocked too. Preventing the usual avoidance response allows extinction to occur, a process Yates (1970) called “forced reality testing”.
This is a world away from Wolpe’s gentle, client-paced hierarchy, and a much harder session to sit through.
Flooding
Flooding works the same way but takes place in real life rather than imagination. A claustrophobic client might be confined in a small space; a flight-phobic client might board an actual aircraft.
The evidence favours it. Marks et al. (1971) compared flooding directly with systematic desensitization and found flooding superior, while Gelder et al. (1973) found no real difference between flooding and implosion.
Real exposure seems to matter most.
A review of flooding studies called it the most universally effective phobia treatment available (Marks, 1981a). Emmelkamp and Wessels (1975) and Marks (1981b) reported similar success treating agoraphobia, with gains still holding after nine years.
No new symptom replaced the phobia in that time. That directly answers the old psychodynamic worry that removing a symptom just relocates the problem.
Flooding is intensely distressing, sometimes provoking real panic in the client. Stopping a session before anxiety subsides can strengthen the very phobia it aims to cure.
It is used only rarely today. Because it shows exposure alone can work, flooding reshaped how psychologists think about therapy: most contemporary exposure work now drops Wolpe’s insistence on paired relaxation.
Critical Evaluation
Practical Issues
Working with images removes many of the practical barriers to in vivo exposure for this type of phobia.
One weakness of in vitro exposure is that it relies on the client’s ability to imagine the fearful situation.
Some people cannot create a vivid image, and thus, systematic desensitization is not always effective (there are individual differences).
Systematic desensitization is a slow process, taking 6-8 sessions on average. However, research suggests that the longer the technique takes, the more effective it is.
The progressive structure of systematic desensitization allows the patient to control the steps he/she must make until fear is overcome.
This gentler process makes clients less likely to abandon therapy.
Theoretical Issues
Systematic desensitization is highly effective where the problem is learned anxiety of specific objects/situations, e.g., phobias (McGrath et al., 1990).
However, systematic desensitization is not effective in treating serious mental disorders like depression and schizophrenia.
Studies have shown that neither relaxation nor hierarchies are necessary and that the important factor is just exposure to the feared object or situation.
Systematic desensitization is based on the idea that abnormal behavior is learned. The biological approach would disagree and say we are born with a behavior, and therefore it must be treated medically.
Treats the symptoms, not the cause(s) of the phobia. Systematic desensitization only treats the observable and measurable symptoms of a phobia.
This is a real weakness. Cognitions and emotions often drive behavior. Treating only the symptoms leaves the deeper causes untouched.
Social phobias and agoraphobia do not seem to show as much improvement. Could it be that there are other causes for phobias than classical conditioning?
For example, if a fear of public speaking originates with poor social skills, then phobic reduction is more likely to occur in a treatment that includes learning effective social skills than systematic desensitization alone.
Relaxation is not important
Researchers discovered that pairing an incompatible response (like relaxation) with the feared stimulus was not actually necessary to reduce anxiety.
Instead, prolonged exposure to the stimulus itself drove the change. The client experienced the fear until it naturally subsided (habituation), or learned the stimulus was safe (inhibitory learning).
Empirical Evidence
Lang and Lazovik (1963) used systematic desensitization with a group of college students who were all suffering from snake phobia. They underwent 11 sessions to work through a hierarchy.
Hypnosis was used to assist in the maintenance of relaxation. The participants’ fear ratings fell, and improvements were still evident six months later.
Rothbaum et al. (2000) used systematic desensitization with participants who were afraid of flying. Following treatment, 93% agreed to take a trial flight.
It was found that anxiety levels were lower than those of a control group who had not received systematic desensitization, and this improvement was maintained when they were followed up six months later.
Aim: Capafons et al. (1998) tested SD for flying phobia.
Method: The researchers recruited 41 aerophobia sufferers through a media campaign in Spain. They treated 20 with SD (a mix of in vivo and in vitro techniques, two one-hour sessions weekly for 12–15 weeks) against a 21-person control group.
Results: All but two of the treated group reported lower fear and showed less anxiety during a flight simulation, measured by self-report and physiological readings. Only one member of the control group improved.
Conclusion: SD was highly effective for fear of flying, though not 100% effective, and the study had no follow-up to confirm the gains lasted.
Contemporary Research
Craske et al. (2014) reframed what makes exposure work. Older approaches, including SD, aimed to lower anxiety within a session. Craske argues the real mechanism is different: the client builds a new “the feared outcome will not happen” memory that competes with the old fear association, called inhibitory learning.
This shifts what good practice looks like. Craske recommends violating the client’s expectations, varying the situations practised, and dropping safety behaviours, rather than sticking to a strict, gentle order.
Virtual reality has become a mainstream tool for exposure work. VR headsets let a client face a controllable, repeatable version of a spider, a height or a flight. It offers much of the realism of in vivo exposure without the practical difficulties.
Ethical Issues
Systematic desensitization increases the client’s sense of self-control: the therapist suggests, guides and helps, without controlling the process.
This technique thus minimizes the risk of dependence on the therapist, or of crediting improvement to something external.
Key Takeaways
- Mechanism: SD pairs relaxation with a graded hierarchy of feared situations so calm gradually replaces fear (reciprocal inhibition).
- Steps: Relaxation training, building an anxiety hierarchy, then working up it while staying relaxed.
- Evidence: Works best for specific phobias (spiders, flying, needles), with controlled trials showing gains still holding six months or more later.
- Active Ingredient: Research suggests exposure itself, not relaxation or the hierarchy, drives the change (Marks, 1973).
- Flooding Alternative: Flooding skips the graded steps and can work as fast or faster, though it is more distressing (Marks et al., 1971).
- Limitations: Less effective for depression, schizophrenia, social phobia and agoraphobia; in vitro work also needs a vivid imagination.
References
Capafons, J. I., Sosa, C. D., & Avero, P. (1998). Systematic desensitization in the treatment of fear of flying. Psychology in Spain, 2(1), 11-16.
Craske, M. G., Treanor, M., Conway, C. C., Zbozinek, T., & Vervliet, B. (2014). Maximizing exposure therapy: An inhibitory learning approach. Behaviour Research and Therapy, 58, 10-23.
Gelder, M., Bancroft, J., Gath, D. H., Johnston, D. H., Matthews, A. M., & Shaw, P. M. (1973). Specific and non-specific factors in behaviour therapy. British Journal of Psychiatry, 123(4), 445-462.
Jones, M. C. (1924). A laboratory study of fear: The case of Peter. Pedagogical Seminary, 31, 308-315.
Lang, P. J., & Lazovik, A. D. (1963). Experimental desensitization of phobia. The Journal of Abnormal and Social Psychology, 66(6), 519.
Marks, I. M. (1981). Cure and care of neurosis. Wiley.
Marks, I. M., Boulougouris, J., & Marset, P. (1971). Flooding versus desensitization in the treatment of phobic patients: A crossover study. British Journal of Psychiatry, 119(551), 353-375.
McGrath, T., Tsui, E., Humphries, S., & Yule, W. (1990). Successful Treatment of a Noise Phobia in a Nine‐year‐old Girl with Systematic Desensitisation in vivo. Educational Psychology, 10(1), 79-83.
Menzies, R. G., & Clarke, J. C. (1993). A comparison of in vivo and vicarious exposure in the treatment of childhood water phobia. Behavior Research and Therapy, 31(1), 9-15.
Rothbaum, B. O., Hodges, L., Smith, S., Lee, J. H., & Price, L. (2000). A controlled study of virtual reality exposure therapy for the fear of flying. Journal of Consulting and Clinical Psychology, 68(6), 1020.
Wolpe, J. (1958). Psychotherapy by reciprocal inhibition. Stanford University Press.
Wolpe, J. (1964). Behavior therapy in complex neurotic states. British Journal of Psychiatry, 110(464), 28-34.
Wolpe, J. (1969). For phobia: A hair of the hound. Psychology Today, 3, 34-37.
Yates, A. J. (1970). Behaviour therapy. Wiley.
