Validity of Classification of Externalizing Disorders

There is increasing recognition that the externalizing disorders continue into adulthood or cause substantial impairment that may persist into adulthood. These disorders place substantial demands on the health care, education and legal resources and have considerable public health importance. The concept and the nosology of the externalizing disorders have evolved considerably over the last few decades. Efforts were made to keep DSM-IV (Diagnostic and Statistical Manual) and ICD-10 (International Classification of Diseases) close to each other to enhance international consensus and subsequently the validity of these disorders. This article aims to review the conceptual basis and the debate over the nosology of externalizing disorders with a view to examine the validity of ICD-10 diagnoses. INTRODUCTION There are certain disorders in childhood and adolescence that predominantly manifest through behaviour, activity and conduct and are called externalizing disorders. Kovacs & Devlin described dysregulated behavior as the central feature of such disorders. These disorders appear under the rubric of Attention Deficit and Disruptive Behavior Disorders in DSM-IV-TR and include attention deficit hyperactivity disorder (ADHD), conduct disorder (CD) and oppositional defiant disorder (ODD). ICD-10 describes two categories viz. hyperkinetic disorder (HD) and conduct disorder. Oppositional disorder appears as a subtype of CD in ICD-10. The disorders are grouped together to emphasize their shared features and areas of impairments. Externalizing disorders are the most common disorders of the childhood and are associated with male sex and a high degree of co morbidity. Impulsivity, poor executive control and callous unemotional traits lead to impairments in scholastic skills and general development. There is increasing recognition that these disorders continue into adulthood or cause substantial impairment that may persist into adulthood. These disorders place substantial demands on the health care, education and legal resources in the community and have considerable public health importance. The concept and the nosology of externalizing disorders have evolved considerably over the past few decades. There have been major changes in the diagnostic criteria in different versions of the DSM. An attempt has also been made to keep DSM-IV and ICD-10 close to each other so as to enhance international consensus and subsequently the validity of these disorders. Nevertheless, an examination of the validity of ICD-10 externalizing disorders raises some important questions: