Do classification systems make a difference? A presentation at the 2022 APA Annual Meeting noted 4 key diagnoses that differ significantly in the classification systems.
Michael B. First, MD, editor and co-chair of DSM-5-TR and chief editorial and technical consultant for ICD-11 Mental and Behavioral Disorders, discussed major classification differences between DSM-5 and the World Health Organization (WHO) International Classification of Diseases (ICD)-11 at the 2022 American Psychiatric Association Annual Meeting.
First, who is also professor of clinical psychiatry in the Columbia University Department of Psychiatry and a member of the Psychiatric TimesTM Editorial Board, began the session with a brief history of each classification system and past efforts toward harmonization. He also provided reasons for their divergent perspectives on the same data, including differing priorities and concentrations in the APA and the WHO, along with a mutual unwillingness to surrender control.
First, editor and co-chair of DSM-5-TR and chief editorial and technical consultant for ICD-11 Mental and Behavioral Disorders, provided detailed examples of 4 diagnoses that differ significantly in DSM-5 versus ICD-11: severe childhood irritability and anger, compulsive sexual behavior disorder, personality disorders, and substance use disorders/substance dependence. DSM-5 classifies severe childhood irritability and anger as disruptive mood dysregulation disorder, while ICD-11 classifies it as oppositional defiant disorder with chronic irritability. Although compulsive sexual behavior disorder was classified as hypersexual disorder and modeled after substance dependence in previous DSM versions, DSM-5 does not include compulsive sexual behavior disorder at all; ICD-11 classifies it as compulsive sexual behavior disorder. DSM-5 retains general personality disorder criteria and 10 specific personality disorder categories that remain unchanged from DSM-IV. ICD-11 implemented a dimensional model for personality disorders incorporating assessments of general personality disorder diagnostic requirement, severity, and personality trait domains, followed by an assignment of Borderline Qualifier (if applicable). Although substance use disorder/substance dependence had similar diagnoses in DSM-IV and ICD-10, DSM-5 introduced a more dimensional approach incorporating 7 DSM-IV dependence items, 3 DSM-IV abuse items (minus substance-related legal problems), 1 new item (craving), and levels of severity from mild to severe. ICD-11 retained the ICD-10 categories of substance dependance and harmful use.
First ended the presentation with a comparison of advantages and disadvantages to these and other diagnostic differences in DSM and ICD. He stated that these differences are advantageous in that they allow for classifications to be optimized to meet the needs of user groups; facilitate testing to see which nosological approaches are the most valid and clinically useful; support the expansion and improvement of validity in clinical research over time; and create new opportunities for the developers of diagnostic instruments and measurement tools. However, he noted that the differences complicate the way health statistics are collected and reported in nations that use DSM. Other disadvantages include the inability to compare study results that were assessed using different systems; and drug testing and approval in cases where clinical indications were assessed using different systems. The differences also impose an added burden on developers of diagnostic instruments and measuring tools.
The relationship between DSM and ICD “is an ongoing story,” First told attendees. “We’ll see how it turns out.”