Flooding (also known as implosion therapy) is a type of exposure therapy that works by exposing the patient directly to their worst fears. (S)he is thrown in at the deep end.
The technique is based on the principle of extinction, which suggests that when a person is exposed to a feared stimulus repeatedly and for a prolonged period without any negative consequences occurring, their fear response will diminish.
Flooding Exposure Therapy
Flooding aims to help individuals confront their fears directly and experience the absence of harm or negative outcomes, leading to the extinction of their anxiety response. The exposure is immediate, not gradual.
For example, a claustrophobic will be locked in a closet for 4 hours, or an individual with a fear of flying will be sent up in a light aircraft.
Flooding aims to expose the sufferer to the phobic object or situation in a safe and controlled environment for an extended period. Unlike systematic desensitization, which might use in vitro or virtual exposure, flooding generally involves in vivo exposure.
How Flooding Works
Fear is a time-limited response. At first, the person is in extreme anxiety, perhaps even panic, but eventually, exhaustion sets in, and the anxiety level decreases.
Of course, normally, the person would do everything possible to avoid such a situation. Now they have no choice but to confront their fears. When the panic subsides, they find they have come to no harm. The fear, which was largely anticipatory, is extinguished.
Prolonged intense exposure eventually creates a new association between the feared object and something positive, such as a sense of calm and lack of anxiety. It also prevents the reinforcement of phobia through escape or avoidance behaviors. Like systematic desensitisation, flooding rests on the principles of classical conditioning.
The imaginal version is usually called implosion, covered next. Flooding can also take place in real life, known as in vivo exposure.
Implosion Therapy
Implosion therapy is the imaginal form of flooding. Instead of building up to the most frightening scenario gradually, the patient is asked to imagine their worst fear straight away. Imagination is useful here because some fears, like a fear of failure, are too abstract to confront directly.
The imagery must feel real.
The therapist adds vivid verbal descriptions to intensify this imagery, a technique called stimulus augmentation. It can take time. Anxiety is deliberately kept high until exhaustion or stimulus satiation sets in, and it can then only fall.
Because the patient cannot escape or avoid the imagined scenario, the usual avoidance response is prevented and the fear response extinguishes. Yates (1970) called this “forced reality testing”: the patient discovers first-hand that the feared consequence does not happen.
Critical Evaluation
Flooding is rarely used, and it can be dangerous if you are not careful. It is not an appropriate treatment for every phobia.
It should be used cautiously as some people can increase their fear after therapy, and it is impossible to predict when this will occur.
Wolpe (1969) reported the case of a client whose anxiety intensified to such a degree that flooding therapy resulted in her being hospitalized.
Some people cannot tolerate the high levels of anxiety the therapy induces. They may exit before they feel calm and relaxed.
This is a problem: exiting treatment before completion is likely to strengthen, not weaken, the phobia.
However, one application is for people who fear water (they are forced to swim out of their depth). It is also sometimes used with agoraphobia.
In general, flooding produces results as effective (sometimes even more so) as systematic desensitization.
Aim: To compare flooding with systematic desensitisation.
Method: Marks et al. (1971) ran a crossover study comparing flooding with desensitisation in phobic patients.
Results: Flooding produced superior outcomes to desensitisation; a related study found no difference between desensitisation and implosion (Gelder et al., 1973).
Conclusion: In-vivo exposure, not relaxation or a graded hierarchy, appears to be the active ingredient in successful treatment.
The method’s success supports one key idea. Phobias persist because the object is avoided in real life, so it is never disconfirmed as harmless.
For example, Wolpe (1960) forced an adolescent girl with a fear of cars into the back of a car and drove her around continuously for four hours. Her fear reached hysterical heights but then receded, and by the end of the journey it had completely disappeared.
Contemporary Research
Virtual reality now offers a further way to deliver flooding and other exposure-based treatments, providing safe, standardised and repeatable exposure to feared stimuli such as heights, flying or spiders.
Craske et al. (2014) proposed a different mechanism: inhibitory learning. It is a new “the feared outcome will not happen” memory that competes with the original fear memory, rather than on reducing anxiety within a single session.
This model favours strategies such as maximising the mismatch between what a client expects and what actually happens, and varying the contexts of exposure.
Fear can sometimes return even after successful treatment. Bouton (2004) explains why: extinction does not erase the original fear memory, it only adds new, context-dependent learning on top of it. This new learning is tied to context, so the fear can resurface through spontaneous recovery, renewal or reinstatement.
Key Takeaways
- What It Is: Flooding exposes a person directly to their most feared object or situation, without any gradual build-up.
- Implosion: The imaginal version of flooding, where the patient imagines the worst-case scenario straight away.
- Mechanism: Anxiety cannot stay at its peak indefinitely. Exhaustion sets in, and the feared outcome never happens.
- Effectiveness: Comparative studies show flooding works as well as, and sometimes better than, systematic desensitisation (Marks et al., 1971).
- Ethical Risk: Ending a session too early, before anxiety subsides, can make a phobia worse rather than better.
- Modern Use: Because of its intensity, flooding is now used only rarely in clinical practice.
References
Bouton, M. E. (2004). Context and behavioral processes in extinction. Learning & Memory, 11(5), 485-494.
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.
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.
Skinner, B. F. (1938). The Behavior of organisms: An experimental analysis. New York: Appleton-Century.
Wolpe, J. (1958). Psychotherapy by reciprocal inhibition. Stanford, CA: Stanford University Press.
Wolpe, J. (1960). In behavior therapy and the neuroses.
Wolpe, J. (1969). Basic principles and practices of behavior therapy of neuroses. American Journal of Psychiatry, 125(9), 1242-1247.
Further Information
- Aversion Therapy: How It Works & What to Expect
- List of Support Groups
- Campaign against Living Miserably
- Men do cry: one man’s experience of depression
- NHS Self-Help Guides
- Wolpe, J., & Plaud, J. J. (1997). Pavlov’s contributions to behavior therapy: The obvious and the not so obvious. American Psychologist, 52(9), 966.
