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Section 12
Obsessive-Compulsive Disorder Part One

Question 12 | Test | Table of Contents

Obsessive–compulsive disorder (OCD) has enjoyed a resurgence of scientific interest since the Epidemiological Catchment Area (ECA) study in the USA suggested that it is not at all a rare disorder; indeed, it became known as the ‘hidden epidemic’, testament to the alleged degree of hitherto unrecognised morbidity in the general population. But how common is OCD really? As with any of the anxiety disorders, the symptoms associated with OCD are extremes on a normal continuum, and the stage at which they become a ‘disorder’ is a moot point. The DSM rubric of ‘significant distress’ or ‘impairment of functioning’ is useful enough, but fails to reflect the fact that subjective appraisal of these parameters is often incompatible with objective considerations. For example, an agoraphobia sufferer who is entirely confined to her house by her fears, might not consider herself to be significantly distressed (because the feared situations are always avoided), nor impaired in functioning (because her family has rallied around, support and cosset her, doing the shopping for her, etc.). However, any objective measure of functioning would undoubtedly rate her as impaired. The obverse of this is that some individuals rate themselves as very distressed and disabled by anxiety symptoms, while more objective appraisal does not bear this out.

A question of definition
This scenario also pertains to OCD, and is at the heart of any attempt to define incidence and prevalence of the disorder. The problems associated with definition are no more clearly evident than in a closer consideration of the ECA data themselves. Readers will be aware that the ECA study relied on the Diagnostic Interview Schedule (DIS), a lay-administered, structured interview, to define caseness. The lifetime prevalence of OCD according to the DIS, ranged from 1.9% to 3.2% across the five ECA sites. There are, however, immediate problems with acceptance of these figures on face value. For example, the lifetime prevalence is incompatible with the reported 1-year’s incidence rate of around 0.8%, for a usually chronic disorder. Furthermore, the reported gender ratio of patients of 2:1 female : male, is higher than in most clinical samples. And in terms of symptoms, obsessions and compulsions reportedly occurred together in only 9% of cases, discrepant with the close to 90% co-occurrence in clinical samples.

In a study to assess the validity of the ECA data, Anthony and colleagues investigated the extent to which DIS diagnoses of OCD (and other disorders) tallied with expert clinician diagnosis. Concentrating on the Baltimore ECA site, a subsample of the DIS interviewed cohort were independently assessed by psychiatrists, and all available data were then subjected to a ‘clinical reappraisal’ (CR) by psychiatrists. For DSM-III defined OCD, the 1-month prevalence rate according to the DIS was 1.3%, while the CR figure was 0.3%. What is more worrying is that the proportion of DIS-positive OCD cases that were also considered cases by CR, was 0.04. In terms of statistical agreement between the two diagnoses, the kappa was only 0.05. In a separate study, Nelson and Rice re-interviewed individuals ascertained as ‘cases’ of OCD in the ECA study, after an interval of 1 year and reported a stability of diagnosis of only 0.2 (kappa statistic). Put another way, only 56 (19%) of the 291 original OCD ‘cases’ were re-diagnosed at 1 year. Individuals with obsessions and compulsions were twice as likely to have a ‘stable’ diagnosis, as were those with an early onset of illness. A further example of the problems associated with making a definitive diagnosis of OCD in a large-scale epidemiological study, is the investigation by Stein et al. from Canada. In this study, lay interviewers used a telephone version of the Composite International Diagnostic Interview (CIDI), to interview a general population sample of 2261 people. Fully 26.2% of the sample reported having experienced obsessions, and 22.2% compulsions. However, few of these individuals considered their obsessions and compulsions to be unreasonable or excessive, repetitive or recurrent, or excessively time-consuming (> 1 h/day); thus, only 69 people (3.1%) met DSM-IV criteria for OCD. However, when a subsample of these ‘cases’ was re-interviewed by research personnel, using the Structured Clinical Interview for DSM-IV (SCID), only one-quarter were considered truly to meet DSM-IV criteria, giving a revised 1-month prevalence of 0.6%. The majority of discordance between the CIDI-positive and SCID-positive cases was due to a labelling of ordinary sources of worry or concern as ‘obsessions’, and a tendency to accept reports of ‘distress’ and ‘disability’ too readily, on the basis of patient report. One way around some of these problems is to ascertain symptoms, rather than define ‘caseness’ as such. Some indication of the utility of this approach can be found in those epidemiological studies which have adopted the Present State Examination (PSE), which essentially determines presence or absence of symptoms, either currently, or over the individual’s lifetime. In the study of Bebbington et al., the PSE was used to interview a stratified subsample of 310 of an original 800 people randomly selected from the general population of Camberwell, southeast London. The PSE questions pertaining to OCD included items on checking, washing and ruminations; rates were 9.1%, 1.6%, and 0.9%, respectively.

Looked at another way, however, the actual number of ‘cases’ of OCD, on clinical review by a psychiatrist, was only one patient with OCD ‘severe enough to warrant treatment’; many other individuals with OCD symptoms were considered to have manifested these symptoms secondary to another disorder (mostly depression), or to have symptoms too mild to warrant treatment.  So, how common is OCD? The question is unanswerable, the answer dependent upon the definition of the disorder, and the internal ‘boundaries’ imposed by diagnostic systems. A range of anything from 0.05% to 3.50% lifetime prevalence is possible to defend, a close to one hundred-fold difference. Perhaps more useful is focusing our attention, as clinicians, on individuals, and their particular symptoms, and how these symptoms are perceived by them and how they impact on their lives. If we are unclear about the ‘internal’ boundaries of OCD (i.e. what precise set of symptoms are required to be present for the diagnosis), we are equally unclear about the ‘external’ boundaries of the disorder.

Thus, there are a number of other psychiatric and neuropsychiatric disorders whose symptomatology shows many similarities with OCD. This raises important questions with respect to whether some of these disorders might have aetiological links, and/or share similar pathogenetic mechanisms, with OCD. To inform these issues, we turn now to a consideration of the external boundaries of OCD, with a review of the so-called ‘OCD spectrum’.

Obsessive–compulsive spectrum disorders
Given the difficulties inherent in defining caseness of OCD, it is worth considering whether the symptoms are in themselves diagnostically useful. One approach is to consider OCD per se to be a disorder with very permeable external boundaries and a great deal of symptomatic overlap with an array of other disorders, including those of ‘impulse control’ (e.g. pathological gambling, kleptomania, trichotilomania), neurological disorders with associated OCD features (e.g. autism, Tourette’s syndrome) and disorders characterised by preoccupation with bodily appearance or sensation (e.g. hypochondriasis, anorexia nervosa, body dysmorphic disorder). The case for the inclusion of each of these disorders in the OCD spectrum can be defended to a greater or lesser degree. For example, a strong case can be made for body dysmorphic disorder (BDD). The defining features of BDD are preoccupation with bodily appearance (intrusive, distressing thoughts recognised by the individual as being excessive; indeed, having all the hallmarks of OCD ruminations), and repeated attempts to reduce the anxiety associated with such intrusive thoughts (i.e. compulsions: mirror checking, ritualised application of make-up, etc.). Furthermore, there is some overlap in familial loading for OCD and BDD (an excess in family risk for OCD in patients with BDD).

The other psychiatric disorders which have been considered to fall within the OCD spectrum can also be considered to lie on an impulsive–compulsive continuum of ‘risk avoidance’. As Hollander puts it, impulsive individuals are seen as ‘risk seekers who try to maximise pleasure, arousal or gratification’, while compulsive individuals ‘attempt to avoid harm or reduce anxiety or discomfort, associated with the rituals’. In this model, disorders such as sexual compulsions and impulsive personality disorders would be considered ‘impulsive’, and hypochondriasis, body dysmorphic disorder, and anorexia nervosa, ‘compulsive’. This model has more than heuristic attraction. Indeed, there is some evidence of different neurochemical substrates of disorders at either end of the continuum. For example, impulsive disorders show a response to serotonergic agents characterised by a rapid response which attenuates over time, while disorders at the compulsive end of the spectrum tend to have a lag time before onset of response, but tend to maintain their gains.

An overlap with psychosis?
We turn now to a consideration of OCD and psychosis, to explore whether a definite distinction can be made between psychotic processes, and those processes underpinning obsessive–compulsive symptoms. Although textbooks tend to draw an absolute distinction between obsessional thoughts on the one hand, and delusions on the other, it is increasingly recognised that obsessional thoughts can come to be believed, by their tormentee, with a strength of conviction that places them in the delusional spectrum. Indeed, Insel and Akiskal have argued that OCD ‘represents a psychopathological spectrum varying along a continuum of insight’, and that at the extreme end of the spectrum, patients could be considered to have ‘obsessive–compulsive psychosis’.  Of course, clinicians should be wary about accepting bizarre and firmly held beliefs as anything other than an indication of a psychotic process, but the recognition that OCD can become ‘delusional’ is important, as treatment should be directed at the ‘primary’ pathology.

Having said this, it has long been recognised that a patient with an evolving psychotic process can present with obsessive–compulsive symptoms; the unwary clinician can be misled and delay appropriate antipsychotic therapy. In more established cases of schizophrenia, OCD is also overrepresented. For example, Eisen et al. found that 6 (7.8%) of 77 patients with schizophrenia or schizoaffective disorder also met DSM-III-R criteria for OCD. In an early consideration of this overlap, Stengel explored the ‘interrelationship between neurotic manifestations and psychotic reaction types’, and concluded that ‘the excessive inclination of the obsessional neurotics to reality proving and doubt affected their attitude to psychotic experiences in a favourable way’. Thus, he foreshadowed the current vogue for cognitive–behavioural interventions for individuals with psychotic symptomatology.

An overlap with Axis II disorders?
In a further consideration of the external boundaries of OCD, we now explore the relationship between obsessive–compulsive personality disorder, and OCD. Conventional wisdom has it that individuals with obsessional traits are particularly prone to OCD, but it is often difficult to tease apart the DSM Axis I and Axis II pathology, expressly in early onset cases. Baer et al. assessed 96 patients with OCD, for personality disorder diagnoses, using a standardised interview schedule for DSM-III Axis II disorders. They found that 52% of the OCD subjects met criteria for at least one personality disorder, with the most common diagnosis being of mixed, histrionic and dependent types. Indeed, only six patients met criteria for obsessive–compulsive personality disorder, and 5 of these had experienced an onset of OCD before the age of 10 years. Thus, obsessive– compulsive personality disorder appears not usually to be the soil out of which OCD grows, and this challenges the current nosology. Furthermore, it is highly questionable whether one can apply a personality disorder label to patients with a very early onset of illness, and some individuals attracting a label of obsessive–compulsive personality disorder almost certainly merely have a severe early onset form of OCD.
- Castle, David J.; Groves, Aaron. Australian and New Zealand Journal of Psychiatry 2000.

Personal Reflection Exercise #5
The preceding section contained information about the internal and external boundaries of obsessive-compulsive disorder. Write three case study examples regarding how you might use the content of this section in your practice.

Cognitive-Behavioral Therapy for
Obsessive-Compulsive Disorder

Öst, L. G., Enebrink, P., Finnes, A., Ghaderi, A., Havnen, A., Kvale, G., Salomonsson, S., & Wergeland, G. J. (2022). Cognitive behavior therapy for obsessive-compulsive disorder in routine clinical care: A systematic review and meta-analysis. Behaviour research and therapy, 159, 104170.

Peer-Reviewed Journal Article References:
Barrera, T. L., McIngvale, E., Lindsay, J. A., Walder, A. M., Kauth, M. R., Smith, T. L., Van Kirk, N., Teng, E. J., & Stanley, M. A. (2019). Obsessive-compulsive disorder in the Veterans Health Administration. Psychological Services, 16(4), 605–611.

McKay, D., Abramowitz, J. S., & Storch, E. A. (2021). Mechanisms of harmful treatments for obsessive–compulsive disorder. Clinical Psychology: Science and Practice, 28(1), 52–59.

Solomonov, N., Kuprian, N., Zilcha-Mano, S., Muran, J. C., & Barber, J. P. (2020). Comparing the interpersonal profiles of obsessive-compulsive personality disorder and avoidant personality disorder: Are there homogeneous profiles or interpersonal subtypes? Personality Disorders: Theory, Research, and Treatment. Advance online publication.

How does Hollander define impulsive and compulsive individuals? To select and enter your answer go to Test

Section 13
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