Accuracy of diagnostic judgments using ICD-11 vs. ICD-10 diagnostic guidelines for obsessive-compulsive and related disorders.

Background: We report results of an internet-based field study evaluating the diagnostic guidelines for the newly introduced ICD-11 grouping of obsessive-compulsive and related disorders (OCRD). We examined accuracy of clinicians' diagnostic judgments applying draft ICD-11 as compared to the ICD-10 diagnostic guidelines to standardized case vignettes.

Methods: 1,717 mental health professionals who are members of the World Health Organization's Global Clinical Practice Network completed the study in Chinese, English, French, Japanese, Russian or Spanish. Participants were randomly assigned to apply ICD-11 or ICD-10 guidelines to one of nine pairs of case vignettes.

Results: Participants using ICD-11 outperformed those using ICD-10 in correctly identifying newly introduced OCRD, although results were mixed for differentiating OCRD from disorders in other groupings largely due to clinicians having difficulty differentiating challenging presentations of OCD. Clinicians had difficulty applying a three-level insight qualifier, although the 'poor to absent' level assisted with differentiating OCRD from psychotic disorders. Brief training on the rationale for an OCRD grouping did not improve diagnostic accuracy suggesting sufficient detail of the proposed guidelines.

Limitations: Standardized case vignettes were manipulated to include specific characteristics; the degree of accuracy of clinicians' diagnostic judgments about these vignettes may not generalize to application in routine clinical practice.

Conclusions: Overall, use of the ICD-11 guidelines resulted in more accurate diagnosis of case vignettes compared to the ICD-10 guidelines, particularly in differentiating OCRD presentations from one another. Specific areas in which the ICD-11 guidelines did not perform as intended provided the basis for further revisions to the guidelines.