Clinical Classification of OCD

When working with patients, health professionals often refer to clinical diagnostic manuals to better understand the patient's illness and potential treatment. There are two main recognised diagnostic manuals commonly used around the world today.

The International Classification of Diseases (ICD), is the international standard diagnostic classification for all recognised diseases and related health problems and is mainly used in the UK and much of Europe. ICD codes are alphanumeric designations given to every diagnosis and description of symptoms on medical records. These classifications are developed and monitored by the World Health Organization (WHO).

The ICD is revised periodically and is currently in its tenth edition, the ICD-10, as it is known, was developed in 1992 and the next version, ICD-11 is planned for publication in 2015.

The DSM-IV-TR, is the other diagnostic manual mainly used around the world, and is the American counterpart of ICD-10.

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is published by the American Psychiatric Association and provides clinicians with official definitions of, and criteria for, diagnosing mental disorders.

There have been five revisions since it was first published in 1952, the last major revision was the fourth edition ‘DSM-IV’, published in 1994, although a text revision was produced in the year 2000. The fifth edition ‘DSM-5’ is currently in consultation, planning and preparation, due for publication in May 2013.

Here in the UK, in addition to the ICD-10 and the DSM-IV, the National Institute for Health and Clinical Excellence (NICE) launched their own set of clinical guidelines for the identification, treatment and management of Obsessive-Compulsive Disorder and Body Dysmorphic Disorder, for both children and adults, on the 23rd November 2005.

NICE is an independent organisation, responsible for providing national guidance in England and Wales in respect of the promotion of good health and the prevention and treatment of ill health. Clinical guidelines are recommendations on the appropriate treatment and care of people with specific diseases and conditions within the NHS in England and Wales. They are based on the best available evidence and the guidelines are produced to try to help healthcare professionals in their work.

At present the European International Classification of Diseases (ICD) currently lists OCD in its own subcategory under the category of Neurotic, Stress-related and Somatoform Disorders (F40-F48), although within the same larger category as other anxiety disorders.

With regard to the essential features of OCD, the ICD-10 and DSM-IV-TR manuals state the following diagnostic criteria for Obsessive-Compulsive Disorder.

The International Classification of Diseases (ICD-10) Classification of Obsessive-Compulsive Disorder (ICD-10 Code F42) The essential feature of this disorder is recurrent obsessional thoughts or compulsive acts. (For brevity, "obsessional" will be used subsequently in place of "obsessive-compulsive" when referring to symptoms.) Obsessional thoughts are ideas, images or impulses that enter the individual's mind again and again in a stereotyped form. They are almost invariably distressing (because they are violent or obscene, or simply because they are perceived as senseless) and the sufferer often tries, unsuccessfully, to resist them. They are, however, recognized as the individual's own thoughts, even though they are involuntary and often repugnant. Compulsive acts or rituals are stereotyped behaviours that are repeated again and again. They are not inherently enjoyable, nor do they result in the completion of inherently useful tasks. The individual often views them as preventing some objectively unlikely event, often involving harm to or caused by himself or herself. Usually, though not invariably, this behaviour is recognized by the individual as pointless or ineffectual and repeated attempts are made to resist it; in very long-standing cases, resistance may be minimal. Autonomic anxiety symptoms are often present, but distressing feelings of internal or psychic tension without obvious autonomic arousal are also common. There is a close relationship between obsessional symptoms, particularly obsessional thoughts, and depression. Individuals with obsessive-compulsive disorder often have depressive symptoms, and patients suffering from recurrent depressive disorder may develop obsessional thoughts during their episodes of depression. In either situation, increases or decreases in the severity of the depressive symptoms are generally accompanied by parallel changes in the severity of the obsessional symptoms.

Obsessive-compulsive disorder is equally common in men and women, and there are often prominent anankastic features in the underlying personality. Onset is usually in childhood or early adult life. The course is variable and more likely to be chronic in the absence of significant depressive symptoms.

Diagnostic Guidelines For a definite diagnosis, obsessional symptoms or compulsive acts, or both, must be present on most days for at least 2 successive weeks and be a source of distress or interference with activities. The obsessional symptoms should have the following characteristics: (a) they must be recognized as the individual's own thoughts or impulses: (b) there must be at least one thought or act that is still resisted unsuccessfully, even though others may be present which the sufferer no longer resists; (c) the thought of carrying out the act must not in itself be pleasurable (simple relief of tension or anxiety is not regarded as pleasure in this sense); (d) the thoughts, images, or impulses must be unpleasantly repetitive.


  • anankastic neurosis
  • obsessional neurosis
  • obsessive-compulsive neurosis

Excludes: obsessive-compulsive personality (disorder) ( F60.5 )

Differential Diagnosis Differentiating between obsessive-compulsive disorder and a depressive disorder may be difficult because these two types of symptoms so frequently occur together. In an acute episode of disorder, precedence should be given to the symptoms that developed first; when both types are present but neither predominates, it is usually best to regard the depression as primary. In chronic disorders the symptoms that most frequently persist in the absence of the other should be given priority.
Occasional panic attacks or mild phobic symptoms are no bar to the diagnosis. However, obsessional symptoms developing in the presence of schizophrenia, Tourette's syndrome, or organic mental disorder should be regarded as part of these conditions.
Although obsessional thoughts and compulsive acts commonly coexist, it is useful to be able to specify one set of symptoms as predominant in some individuals, since they may respond to different treatments.

F42.0 Predominantly Obsessional Thoughts Or Ruminations These may take the form of ideas, mental images, or impulses to act. They are very variable in content but nearly always distressing to the individual. A woman may be tormented, for example, by a fear that she might eventually be unable to resist an impulse to kill the child she loves, or by the obscene or blasphemous and ego-alien quality of a recurrent mental image. Sometimes the ideas are merely futile, involving an endless and quasi-philosophical consideration of imponderable alternatives. This indecisive consideration of alternatives is an important element in many other obsessional ruminations and is often associated with an inability to make trivial but necessary decisions in day-to-day living.
The relationship between obsessional ruminations and depression is particularly close: a diagnosis of obsessive-compulsive disorder should be preferred only if ruminations arise or persist in the absence of a depressive disorder.

F42.1 Predominantly Compulsive Acts (Obsessional Rituals) The majority of compulsive acts are concerned with cleaning (particularly hand-washing), repeated checking to ensure that a potentially dangerous situation has not been allowed to develop, or orderliness and tidiness. Underlying the overt behaviour is a fear, usually of danger either to or caused by the patient, and the ritual act is an ineffectual or symbolic attempt to avert that danger. Compulsive ritual acts may occupy many hours every day and are sometimes associated with marked indecisiveness and slowness. Overall, they are equally common in the two sexes but hand-washing rituals are more common in women and slowness without repetition is more common in men. Compulsive ritual acts are less closely associated with depression than obsessional thoughts and are more readily amenable to behavioural therapies.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) Classification of Obsessive-Compulsive Disorder (DSM-IV Code 300.3) A. Either obsessions or compulsions: Obsessions as defined by (1), (2), (3) and (4): (1) recurrent and persistent thoughts, impulses, or images that are experienced, at some time during the disturbance, as intrusive and inappropriate and that cause marked anxiety or distress. (2) the thoughts, impulses, or images are not simply excessive worries about real-life problems. (3) the person attempts to ignore or suppress such thoughts, impulses, or images, or to neutralize them with some other thought or action. (4) the person recognizes that the obsessional thoughts, impulses, or images are a product of his or her own mind (not imposed from without as in thought insertion).

Compulsions as defined by (1) and (2): (1) repetitive behaviours (e.g., hand washing, ordering, checking) or mental acts (e.g., praying, counting, repeating words silently) that the person feels driven to perform in response to an obsession, or according to rules that must be applied rigidly (2) the behaviours or mental acts are aimed at preventing or reducing distress or preventing some dreaded event or situation; however, these behaviours or mental acts either are not connected in a realistic way with what they are designed to neutralize or prevent or are clearly excessive . B. At some point during the course of the disorder, the person has recognized that the obsessions or compulsions are excessive or unreasonable. Note: This does not apply to children. C. The obsessions or compulsions cause marked distress, are time consuming (take more than 1 hour a day), or significantly interfere with the person's normal routine, occupational (or academic) functioning, or usual social activities or relationships. D. If another Axis I disorder is present, the content of the obsessions or compulsions is not restricted to it (e.g., preoccupation with food in the presence of an Eating Disorders; hair pulling in the presence of Trichotillomania; concern with appearance in the presence of Body Dysmorphic Disorder; preoccupation with drugs in the presence of a Substance Use Disorder; preoccupation with having a serious illness in the presence of Hypochondriasis; preoccupation with sexual urges or fantasies in the presence of a Paraphilia; or guilty ruminations in the presence of Major Depressive Disorder). E. The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.

Specify if: With Poor Insight: if, for most of the time during the current episode, the person does not recognize that the obsessions and compulsions are excessive or unreasonable.
The APA (American Psychiatric Association) (1994) also provides a diagnostic index of OCD subtypes; the categories included are: ‘Cleaners’, ‘Repeaters’, ‘Completers’, ‘Checkers’, ‘Overly Meticulous’, ‘Compulsive Avoider's’, ‘Hoarders’, and ‘Slowness’.
Additional epidemiological facts about the disorder:

  • The ratio of men to women suffering with the disorder is 1:1, although, more specifically, the disorder’s onset is reported to occur earlier in men than women.
  • Studies have demonstrated that at least a third of all adult sufferers have reported it's onset as occurring during childhood or adolescence.

Possible change to DSM-V categorisation of OCD.

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