Thought–action fusion

An important cognitive process in OCD is the way thoughts or images become fused with reality. This process is called ‘thought–action fusion’ or ‘magical thinking’ (Reference RachmanRachman, 1993). Thus, if a person thinks of harming someone, they think that they will act on the thought or might have acted on it in the past. A related process is ‘moral thought–action fusion’, which is the belief that thinking about a bad action is morally equivalent to doing it. Lastly, there is ‘thought–object fusion’, which is a belief that objects can become contaminated by ‘catching’ memories or other people's experiences (Reference Gwilliam, Wells and Cartwright-HattonGwilliam et al, 2004).

Responsibility

One of the core features of OCD is an overinflated sense of responsibility for harm or its prevention. Responsibility is defined here as: ‘The belief that one has power that is pivotal to bring about or prevent subjectively crucial negative outcomes. These outcomes may be actual, that is having consequences in the real world, and/or at a moral level’ (Reference Salkovskis, Richards and ForresterSalkovskis et al, 1995). The difference in OCD is the individual's appraisal of situations: the belief that harm might occur to the self, a loved one or another vulnerable person through what the individual might do or fail to do. Harm is interpreted in the broadest sense and includes mental suffering; for example, some people with obsessive worries about contamination fear they will go ‘crazy’ or that the anxiety will go on for ever. Individuals with OCD believe they can and should prevent harm from occurring, which leads to compulsions and avoidance behaviours.

Non-specific cognitive biases

People with OCD have a number of other cognitive biases (Box 1) that are not necessarily specific to the disorder but, in combination with cognitive fusion and an inflated sense of responsibility, lead to anxiety and compulsive symptoms. The excessively narrow focusing on monitoring for potential threats (e.g. fear of contamination from blood, resulting in constant checking for red marks), even when no immediate threat is present, means that less attention is focused on real events. This reduces the individual's confidence in their memory, which in turn leads to further checking behaviours. Intrusive thoughts, images or urges are often accompanied by an excessive attentional bias on monitoring them. This leads to a heightened cognitive self-consciousness and an increase in the detection of unwanted intrusive thoughts and worries about not performing a compulsion or safety behaviour.

Emotion

The dominant emotion in an obsession may be difficult for some patients to articulate but it is commonly anxiety. Some also experience disgust, especially when they think that they could have been in contact with a contaminant. Others feel ashamed and condemn themselves for having intrusive thoughts of, for example, a sexual or aggressive nature, that they believe they should not have. Occasionally, a person with OCD believes that they are responsible for a bad event in the past; in such cases, the main emotion is guilt. Many individuals are also depressed, with various secondary problems caused by the handicap; comorbidity with a mood disorder is relatively common. At times, anger, frustration and irritability are prominent. Because of the range of emotions, it is not surprising that some patients find it difficult to articulate and untangle their dominant emotion.

Compulsions and safety-seeking behaviours

Compulsions are repetitive behaviours or mental acts that a person feels driven to perform. A compulsion can either be overt and observed by others (e.g. checking that a door is locked) or a covert mental act that cannot be observed (e.g. mentally repeating a certain phrase). Covert compulsions are generally more difficult to resist or monitor, as they are ‘portable’ and easier to perform. The term ‘rumination’ covers both the obsession and any accompanying mental compulsions and acts. As with obsessions, there are many types of compulsion (Box 2).

Early experimental studies established that compulsions, especially cleaning, are reinforcing because they seem to reduce discomfort temporarily. Furthermore they strengthen the belief that, had the compulsion not been carried out, discomfort would have increased and harm may have occurred (or not have been prevented). This increases the urge to perform the compulsion again, and a vicious circle is thus maintained. However, compulsions do not always work by reducing anxiety and are often intermittently reinforcing. Compulsions may function as a means of avoiding discomfort, as in examples of obsessional slowness (Reference VealeVeale, 1993). Compulsions are usually carried out in a relatively stereotyped way or according to idiosyncratically defined rules. The compulsion to hoard refers to the acquisition of and failure to discard possessions that appear to be useless or of limited value, and to cluttering that prevents the appropriate use of living space (Reference Frost and HartlFrost & Hartl, 1996).

The individual's criteria for terminating compulsions are an important factor in their maintenance. Someone without OCD finishes an action such as hand-washing when they can see that their hands are clean; someone with OCD and a fear of contamination finishes not only when they can see that their hands are clean but when they feel ‘comfortable’ or ‘just right’. Others may end a compulsion when they have a perfect memory of an event. These additional criteria for terminating compulsions may cause them to last even longer. Progress in overcoming OCD can be made only when the criteria for terminating a compulsion are restricted to objective criteria.

A ‘safety-seeking behaviour’ is an action taken in a feared situation with the aim of preventing catastrophe and reducing harm (Reference SalkovskisSalkovskis, 1985); it therefore includes compulsions and neutralising behaviours. Neutralising is any voluntary or effortful mental action carried out to prevent or minimise harm and anxiety with the goal of either controlling a thought or changing its meaning to prevent negative consequences from occurring (e.g. visualising that the doctor is telling me that I don't have cancer until I feel relief). Other safety-seeking behaviours include mental activities such as trying to be sure of the accuracy of one's memory, trying to reassure oneself and trying to suppress or distract oneself from unacceptable thoughts. Such behaviours may reduce anxiety in the short term but lead to a paradoxical enhancement of the frequency of the thought in a rebound manner.

Avoidance

Although avoidance is not part of the definition of OCD, it is an integral part of the disorder and is most commonly seen in fears of contamination. An example of avoidance is a woman with a fear of contamination who will not touch toilet seats, door handles or taps used by others. She will hover over the toilet seat, use her elbow to open doors and taps, use rubber gloves to put rubbish in the dustbin, avoid picking up items from the floor, avoid shaking hands with people or touching a substance that looks dangerous to her. Avoidance can also occur mentally: trying not to think or feel something upsetting. Not all situations can be avoided and safety-seeking behaviours are often used within a feared situation.

Linking obsessions, compulsions and avoidance behaviour

The content of obsessions, compulsions and avoidance behaviour in OCD are closely related. For example, when a patient has to touch something that they normally avoid, the compulsive washing starts. When avoidance is high, the frequency of compulsions may be low, and vice versa. If a woman's obsession is of stabbing her baby, she might avoid being alone with him or put all knives or sharp objects out of sight, ‘just in case’. If this fails to reduce her obsession, she may ensure that someone is with her all the time (a safety-seeking behaviour) or try to neutralise the thought in her head. These acts in turn increase her doubts and prevent her from disconfirming her fears, and the cycle continues.

Assessment

Clinical assessment of OCD is summarised in Box 3. The assessment of avoidance requires a rating of predicted distress, so that a hierarchy of avoided situations without safety-seeking behaviours may be identified for therapy, together with an understanding of how the avoidance interacts with the obsessions and the distress experienced. Some patients also try to avoid ideas, thoughts or images by distraction or attempts to suppress them.

The patient's problems, goals in therapy and valued directions (e.g. to be a good parent and partner) should be clearly defined. Progress should be rated on standard outcome scales at regular intervals. The standard observer-rated tool is the Yale–Brown Obsessive–Compulsive Scale (Reference Goodman, Price and RasmussenGoodman et al, 1989). The Obsessive–Compulsive Inventory (Reference Foa, Kozak and SalkovskisFoa et al, 1998) is a standard subjectively rated scale. Patients are usually offered time-limited CBT for between 6 and 20 sessions, depending on the severity and chronicity of the problem. Patients with more severe OCD may require a more intensive programme in a residential unit or in their home.

Family involvement

Some families accommodate an individual's avoidance and compulsions; some are overprotective, aggressive or sarcastic; they may minimise the problem or avoid the individual as much as possible. Sometimes the behaviours associated with the OCD restrict the activities of family members (such as gaining access to the bathroom) or their freedom to use certain rooms in the home because of hoarding. People with OCD may react with aggression when their compulsions are not adhered to by their family. Frequently, family members have different coping mechanisms, leading to further discord when they disagree over the best way of dealing with the situation. Assessment should focus on how different members of the family cope and their attitudes to treatment. The goals of CBT include helping family members to be consistent and emotionally supportive, without accommodating the OCD. They may be encouraged to assist in exposure tasks and behavioural experiments if these would facilitate recovery from OCD.

Exposure and response prevention

Behavioural therapy for OCD is based on learning theory. This posits that obsessions have, through conditioning, become associated with anxiety. Various avoidance behaviours and compulsions prevent the extinction of this anxiety. This theory of the disorder has led to ‘exposure and response prevention’, in which the person is exposed to stimuli that provoke their obsession and then helped not to react with escape and compulsions; repetition of these stages leads to extinction of the feared response. Exposure and response prevention remains a good evidence-based treatment for OCD (National Collaborating Centre for Mental Health, 2005).

Normalising intrusive thoughts and urges

The initial strategy in CBT is to normalise the occurrence of intrusions and to emphasise that they are irrelevant to further action. The patient might be presented with a long list of intrusive thoughts and urges drawn from a community sample or examples that the therapist has personally experienced. Therapist and patient would then discuss the similarities of intrusive thoughts between people with OCD and people without – that is, the content of the thoughts does not differ but the degree of distress, effort and duration does. Patients learn that intrusive thoughts and urges are part of the human condition and are necessary for problem-solving and thinking creatively. Therapy therefore seeks to modify the way the individual interprets the occurrence and/or content of their intrusions, as part of a process of reaching an alternative, less threatening view of intrusive thoughts. The conclusion to be drawn is that the problem lies not with the intrusions but with the meaning that the individual attaches to those thoughts and the various strategies that they adopt to try to control or suppress them. Patients learn that their current strategies increase rather than control the frequency of intrusive thoughts, their levels of distress and the urge to neutralise their thoughts.

Therapy in practice

The formulation

Take the example of Ella, a woman with OCD who has intrusive thoughts of molesting a child. Her therapist would draw up a formulation of the factors maintaining the symptoms and would share it with her (Fig. 1). Engagement may be assisted by a Socratic dialogue and setting up two competing theories to be tested out (Reference Clark, Salkovskis and HackmannClark et al, 1998). The therapist's side of such an interaction is outlined in Box 4. In this example, Ella was able to predict that if theory A were true and she really were a paedophile, then she would be feeling excited at the prospect of babysitting. If, however, theory B were true then she might be feeling very worried and frightened about abusing her niece. The treatment strategy should be to reduce such worries (not to reduce the risk to a child), which were interfering with her ability to be a good aunt and wish to become a mother.

Fig. 1 A formulation in obsessive–compulsive disorder.

Box 4 How does Ella prove to herself that her problem is worrying that she is a paedophile?

Therapist: ‘I want to see if we can build a better understanding of what your problem is and therefore how to solve it. It seems to me there are two explanations to test out. The first explanation, which I will call theory A, is the one you have been using for the past few years, that is, the problem is that you are a paedophile. Theory B, which we would like to test out in therapy, is that you are extremely worried about being a paedophile and in your values care very deeply about children.

Have you noticed that treating it as theory A makes the worry and distress about being a paedophile worse?

Have you ever tried to deal with the problem as if was a worry problem?

Would you be prepared to act as if it was theory B for at least 3 months and then review your progress? You can always go back to treating it as a paedophile problem if it's not working. This will mean gradually dropping all your safety and avoidance behaviours.’

Beliefs about contamination

Thought–object fusion (described above) can be used to enhance exposure to contamination. For example, a person can put the tiniest drop of a contaminant (e.g. urine, saliva, semen) into a large volume of water, so that the water has ‘thoughts’ of contamination. The solution can then be transferred to a hand-held spray with which they can ‘contaminate’ themselves or possessions for which they are responsible. This may lead them to question the process of thought–object fusion, and the usefulness of excessive washing or cleaning and any specific predictions that they had made beforehand.

Beliefs about intolerability of uncertainty

The need for certainty is a common theme in OCD, especially for events in the distant future that are impossible to disprove. For example Mark, the man with OCD mentioned earlier, demands to know for certain whether he is HIV positive, despite repeated reassurance from negative tests or positive explanations for his symptoms. Such patients always have a nagging doubt – the blood sample could have been accidentally switched, there could be a new type of HIV which has not yet been discovered, the sero-conversion has not yet occurred and so on. Mark is demanding a 100% guarantee or absolute certainty, which is of course impossible. However, while he continues to believe that he has to be 100% certain, he will focus on the possible doubts. Obviously the feared situations are possible, but they are highly improbable. It is important not to get involved in a detailed analysis of probabilities but to help the patient to focus on the process and recognise the link between the demand for certainty and their distress and further doubt. This will help them to step back and focus on the much higher likelihood of a poor quality of life if they continue to seek reassurance. Patients can be helped to tackle their beliefs using humour: we can guarantee two things in life – death and taxes! A third guarantee is that while the patient continues to demand a guarantee that a feared consequence will not occur they will continue to disturb themselves with their symptoms.

Beliefs about terminating compulsive behaviours

As has already been noted, people with OCD tend to use problematic criteria such as being ‘comfortable’, ‘just right’ or ‘totally sure’ to terminate a compulsion. Patients can be taught that they are diverting increasing amounts of attention and trying too hard to determine the indeterminable (e.g. whether one can be totally sure everything has been done to make something clean). Patients who check their memory have special difficulty. They are demanding to have a perfect or totally clear picture of everything they have done, in the order that it happened. Socratic questioning can be used to illustrate the impossibility of this demand and how each check creates further ambiguous data and more scope for doubt. The criterion of ‘feeling comfortable’ is particularly impossible to achieve when confronting disturbing fears about the harm that one may cause. In this case, patients should be helped to focus their attention away from their subjective feelings and towards the external world (e.g. what they can see with their eyes or feel with their hands). Alternatively, patients may be shown that demanding to feel comfortable or confident before they can terminate a compulsion or confront a fear is akin to putting the cart before the horse. Patients usually need to do tasks uncomfortably and unconfidently before they can achieve comfort and confidence in doing them.

Hazards of cognitive therapy in OCD

A hazard of cognitive therapy in inexperienced hands is that the therapist becomes engaged in subtle requests for reassurance and arguments about minor probabilities. In such cases, it is especially important to use Socratic dialogue to help the patient generate the information needed by a behavioural experiment, or to ask the patient how a colleague or relative would think or act. Most problems in CBT for OCD stem from two failures: challenging the content of intrusive thoughts rather than the patient's appraisal of them or the cognitive process; and not spending enough time on exposure and behavioural experiments. Always relate requests for reassurance or more information to the patient's formulation and the cognitive–behavioural model of OCD, with an emphasis on the effect of various cognitive processes and behaviours.

Key good practice points for using CBT are summarised in Box 5 and further reading is suggested in Box 6.

Declaration of interest

None.

MCQs

1. 1 Neutralising an intrusive thought or image:

   1. a leads to an immediate increase in anxiety

   2. b is an involuntary strategy adopted by the patient

   3. c aims to create more harm

   4. d prevents disconfirmation of the intrusive thought

   5. e is identical to a compulsion.

2. 2 Cognitive processes in OCD include:

   1. a thought–action dissociation

   2. b tolerance of uncertainty

   3. c overinflated sense of responsibility for harm

   4. d finishing washing ritual when seeing that one's hands are clean

   5. e underestimation of the likelihood of harm.

3. 3 Compulsions in OCD:

   1. a can lead to psychosis if resisted

   2. b may initially function as a means of avoiding anxiety

   3. c can be resisted by focusing attention inwards on subjective feelings and not by external information

   4. d are entirely voluntary

   5. e cannot be mental acts.

4. 4 Unwanted intrusive thoughts and images:

   1. a are indistinguishable in content between people with OCD and the ‘normal’ population

   2. b can be suppressed in the long term

   3. c do not differ in the meaning that people with OCD attach to their occurrence and/or content compared with the ‘normal’ population

   4. d are unnecessary for thinking creatively and problem-solving

   5. e are rare in the general population.

5. 5 Assessment for cognitive–behavioural therapy in OCD:

   1. a does not require knowledge of the degree of family involvement

   2. b does not require knowledge of the patient's degree of insight or overvalued ideation

   3. c requires forensic assessment of intrusive thoughts and urges

   4. d requires assessment of the patient's readiness to change

   5. e requires analysis of countertransference.

MCQ answers

1		2		3		4		5
a	F	a	F	a	F	a	T	a	F
b	F	b	F	b	T	b	F	b	F
c	F	c	T	c	F	c	F	c	F
d	T	d	F	d	F	d	F	d	T
e	F	e	F	e	F	e	F	e	F