ABSTRACT
The article reviews the historical background and symptoms of body dysmorphic disorder (BDD) and olfactory reference disorder, and describes the proposals of the WHO ICD-11 Working Group on the Classification of Obsessive-Compulsive and Related Disorders related to these categories. This paper examines the possible classification of BDD symptoms in ICD-10. Four different possible diagnoses are found (hypochondriacal disorder, schizotypal disorder, delusional disorder, or other persistent delusional disorder). This has led to significant confusion and lack of clear identification in ICD-10. Olfactory reference disorder can also be classified as a delusional disorder in ICD-10, but there is no diagnosis for non-delusional cases. The Working Group reviewed the classification and diagnostic criteria of BDD in DSM-5, as well as cultural variations of BDD and olfactory reference disorder that include Taijin Kyofusho. The Working Group has proposed the inclusion of both BDD and olfactory reference disorder in ICD-11, and has provided diagnostic guidelines and guidance on differential diagnosis. The Working Group's proposals for ICD-11 related to BDD and olfactory reference disorder are consistent with available global evidence and current understanding of common mechanisms in obsessive-compulsive and related disorders, and resolve considerable confusion inherent in ICD-10. The proposals explicitly recognize cultural factors. They are intended to improve clinical utility related to appropriate identification, treatment, and resource allocation related to these disorders.