Dimensional Obsessive Compulsive Scale

Rationale

The DOCS was developed primarily because of the need for a measure of obsessive-compulsive (OC) symptoms that maps on to empirically established OC symptom dimensions (or "subtypes") in a conceptually consistent manner. Research consistently finds that OC symptoms distill into the following theme-based dimensions:

A second aim of the DOCS was to address important drawbacks of widely used measures of OCD (such as the Yale-Brown Obsessive Compulsive Scale [YBOCS], Obsessive Compulsive Inventory [OCI and OCI-R] and Padua Inventory [PI and PI-R]). The limitations of these instruments instruments include:

Accordingly, the DOCS:

Development

Items for the DOCS were generated on the basis of research on the dimensionality of OCD symptoms as well as on the parameters of OCD symptom severity. After writing an initial draft of scale items and instructions, the DOCS authors obtained feedback regarding the clarity, reading level, and relevance of these materials from a larger group of (a) experts on OCD, (b) experts on scale development, and (c) people with OCD. Following the incorporation of input from these groups, the final product was a self-report instrument consisting of 20 items; five items for each of the four symptom dimensions (subscales) as described above: (a) contamination, (b) responsibility for harm, injury, or bad luck, (c) unacceptable obsessional thoughts, and (d) symmetry, completeness, and exactness. Hoarding was excluded for the reasons mentioned previously.

DOCS items were worded based on the research-supported idea that obsessions and compulsions are universal experiences, occurring in clinical and nonclinical individuals on a continuum of severity. This allows the DOCS to be viable in both clinical and nonclinical populations.

An analysis of the item reading level revealed that the DOCS is easily understandable for people aged 13–15 years and above or who read at about a 9th-grade level.

Administration and scoring

Each of the four DOCS subscales begins with a general description and broad inclusive examples of the obsessions and compulsions within the particular symptom dimension. Respondents are next asked to consider any obsessions and compulsions within that symptom dimension that they have experienced within the last month and rate (on a scale from 0 [no symptoms] to 4 [extreme symptoms]) (a) the time occupied by obsessions and compulsions, (b) avoidance behavior, (c) associated distress, (d) functional interference, and (e) difficulty disregarding the obsessions and refraining from the compulsions. Thus, the DOCS subscales assesses the severity of the patient's own symptoms, rather than pre-defined symptoms as in most OCD measures. Within each subscale, the five item scores are summed to produce a subscale score (range = 0-20). The four subscale scores can be summed to produce an overall DOCS total score (range = 0-80).

A DOCS total score of 18 optimally distinguishes between someone with OCD and someone without a psychiatric diagnosis; while a score of 21 optimally distinguishes between someone with OCD and someone with an anxiety disorder. As of this time, there are no empirically derived cutoff scores for mild, moderate, or severe OCD symptoms.

Psychometric evaluation

In the initial study describing the development and evaluation of the DOCS, the instrument's factorial validity was supported by exploratory and confirmatory factor analyses of 3 samples, including (a) individuals with OCD, (b) those with other anxiety disorders, and (c) non treatment-seeking individuals. Scores on the DOCS displayed excellent performance on indices of reliability (test-retest, internal consistency) and validity (convergent, divergent, construct), and the measure appears to be sensitive to treatment. The DOCS is also diagnostically sensitive and thus holds promise as a useful measure of OCD symptoms in clinical and research settings.

The factor structure and psychometric properties of the DOCS have been examined in numerous studies in different cultures and languages, and via different methods of administration. Largely, these studies indicate that the scale's properties are consistent cross-culturally and regardless of how it is administered.

Uses

As the DOCS was developed with both clinical and non-clinical samples, it is suitable for use in service delivery settings as well as in research with both treatment-seeking and non-treatment-seeking samples. As it was developed and tested using adults, the DOCS is suitable for individuals age 18 and up. A version for those under 18 is currently in development.

As a self-report instrument, the DOCS requires no special skills to administer. However, interpretation of scores should be carried out by individuals with appropriate training in psychological science. When it is administered to people who have sought professional help, or who are displaying high levels of distress, interpretation should be carried out by appropriately qualified professionals such as a clinical psychologist.

The DOCS is widely used in clinical research on the nature of obsessions and compulsions. It is also used in treatment outcome studies as an measure to evaluate the effects of treatment for OCD.

Permission to use

The copyright for the DOCS belongs to Jonathan Abramowitz, PhD., yet the questionnaire is freely available and may be downloaded and copied without restriction from the DOCS website. It may be distributed or made available electronically, with the restrictions that: (a) the items and instructions are not modified, (b) it is not used or sold for profit, (c) it is used for research or assessment in health settings, and (d) the DOCS is cited in research papers as follows:

Translations and downloads

The DOCS is now available in the following languages: English, Spanish, Japanese, Chinese, Korean, Italian, French, Icelandic, Swedish, German, Norwegian, and Portuguese. All available versions of the DOCS are free to download at https://docs.web.unc.edu/downloads-and-translations/.