The latest edition of the DSM (Diagnostic Manual of Mental Disorders), in addition to taking a more dimensional than categorical approach to mental disorders, involved many important changes. One of them is the new category of disorders, “Obsessive-Compulsive and Related Disorders” .

This new category, also called obsessive-compulsive spectrum, is made up of nine OCD-related disorders. Some of them were previously included in different categories (for example, anxiety disorders or somatoform disorders).

In this article we will know which disorders are included in this spectrum, the changes with respect to the previous version, similarities of these disorders with OCD and their most relevant characteristics.

What is the obsessive-compulsive spectrum?

The obsessive-compulsive spectrum encompasses the so-called “Obsessive-Compulsive and Related Disorders”, and is made up of nine disorders (in a synthesized form): OCD, body dysmorphic disorder, accumulation disorder, excoriation disorder, trichotillomania, induced by another medical illness, substance-induced , other specified and other unspecified.

Obsessive-compulsive spectrum disorders, as we have said, share a series of characteristics, not only at the symptomatic level, but also at the etiological and phenomenological level, which constitutes them as a group of disorders independent of other groups of DSM-5 disorders.

Thus, the obsessive-compulsive spectrum is actually a theoretical classification model , which groups the different disorders mentioned within a spectrum of disorders related to obsessive-compulsive disorder (OCD), as they share notable characteristics of a different nature.

Why this new category?

The creation of this new category of disorders in DSM-5 originates from the similarity of characteristics, manifestations, comorbidity, neuronal circuits involved, etc., of all these disorders. That is, the aim was to create a homogeneous group with unified criteria .

However, there are authors who believe that the expectations of DSM-5 regarding the usefulness of this new chapter and the degree of phenomenological similarity of these disorders have not been met; others, however, do see the creation of this new chapter of obsessive-compulsive spectrum disorders as a necessary, useful, and successful change.

Characteristics of each disorder

Let’s see what each obsessive-compulsive spectrum disorder consists of and where it was previously located in the DSM-IV-TR classification (or also if it is a newly created disorder).

1. OCD (Obsessive-Compulsive Disorder)

OCD is the quintessential disorder on the obsessive-compulsive spectrum. In the previous edition of the DSM (DSM-IV) it was included among the anxiety disorders . However, it was observed that the characteristics of OCD (together with the other disorders of the new category), presented notable similarities, and how it could be considered a group of independent and differentiated disorders.

OCD includes two main symptoms: compulsions and obsessions . In the DSM-IV-TR, both symptoms were necessary to make the diagnosis. In the DSM-5, however, only one of the two (or obsessions or compulsions) is necessary, although both often appear.

2. Body dysmorphic disorder

Body dysmorphic disorder (BDD) was previously (in the DSM-IV-TR) located within the somatoform disorders . However, this disorder (along with others in the category of “OCD and related”) was found to share many characteristics of the obsessive-compulsive spectrum.

Thus, BDD has an important obsessive and a compulsive component. In this way, people who suffer from the disorder manifest obsessive behaviour and/or thoughts in relation to a specific part of their body (for example their nose), and may apply a series of rituals (compulsive behaviour) to reduce the anxiety that their dislike and rejection of that part of the body entails .

3. Accumulation disorder

Accumulation disorder is a new disorder , which did not exist as such in the DSM-IV-TR. However, a similar disorder did exist: Diogenes Syndrome. This syndrome, however, does not exist as an official diagnosis in the DSM, but rather it is a diagnosis that is made in clinical practice to name those patients who compulsively accumulate unnecessary objects. The difference with accumulation disorder is that in Diogenes Syndrome most patients have some pathology affecting the frontal lobe that explains the syndrome. In addition, in Diogenes Syndrome the person also accumulates dirt, as well as objects, and ends up abandoning his or her basic hygiene and care.

In accumulation disorder, however, there is no previous disorder that can explain the symptoms. Accumulation disorder is included in the obsessive-compulsive spectrum because it also presents this type of obsessive-compulsive symptoms .

On the one hand, the person accumulates possessions compulsively and without control over it. On the other hand, he has an obsession to carry out such behaviour, to the extent that the accumulation of objects prevents him from developing a normal life in his home.

4. Excoriation disorder

Excoriation disorder is new in the latest edition of the DSM-5, as is the previous one. This disorder consists of recurrent, non-stop scratching of the skin (especially the face), especially in times of stress and/or anxiety.

These scratching behaviors are compulsive, that is, they are aimed at reducing anxiety, and are irresistible to the patient (he cannot control them, or if he does, it is with significant effort). This is why it is also an obsessive-compulsive spectrum disorder.

5. Trichotillomania

Trichotillomania was classified in the DSM-IV-TR as an “Impulse Control Disorder”, along with others such as Intermittent Explosive Disorder. It was relocated as an obsessive-compulsive spectrum disorder by resembling OCD in some of its manifestations.

In trichotillomania, the person compulsively pulls out his hair (“can’t resist”); often, after doing so, the anxiety is reduced, and the person feels a relief from the tension (as with OCD compulsions, which the patient expresses to reduce anxiety, sometimes caused by the obsessions themselves).

On the other hand, we can think about the closeness of trichotillomania to OCD, since the disorder is more common in people with OCD and their first-degree relatives than in the general population. For this and other reasons, it’s classified as an obsessive-compulsive spectrum disorder.

6. Medically/substance induced

Here correspond the so-called “Obsessive-Compulsive and Related Disorders induced by another medical illness”; as its own name indicates, appear as a consequence of a previous illness or of the ingestion of certain types of psychoactive substances (or because of their abstinence syndrome).

Thus, any of the above disorders caused by an underlying medical illness or substance use (or withdrawal) are grouped together.

Difference between drive and compulsion

To conclude, it is important to have some clear specifications in order to make a good differential diagnosis. One of them is to know the difference between a drive and a compulsion (being this a characteristic of the obsessive-compulsive spectrum). Broadly speaking, the basic difference between an impulsive act and a compulsive act is that in the former, the person feels pleasure in carrying out the impulsive behaviour; in the compulsive act, on the other hand, more than pleasure, what the person feels is a release of tension and discomfort.

Bibliographic references:

  • American Psychiatric Association. (1994). Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: APA. (English translation: Barcelona: Masson, 1998).
  • American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: APA. (English translation: Madrid: Editorial Médica Panamericana, 2014).
  • Castelló, T. (2014). The obsessive-compulsive spectrum in the DSM 5. Revista iberoamericana de psicosomática, 112: 23 – 27.