Behavioral excess and disruptive conduct: A historical and taxonomic approach to the origin of the 'impulse control disorders' diagnostic construct.

Aims: Impulse control disorders (ICDs) are iatrogenic and idiopathic conditions with psychosocial and economic consequences for the affected individuals and their families (e.g. bankruptcy and divorce). However, the definition of ICDs has changed over time, and ICDs are not consistently included within existing taxonomies. We discuss the origins of the ICD diagnostic construct and its unsolved tensions.

Methods: To contextualize the ICD diagnostic construct, we provided an overview of its origins in past centuries and followed its development across multiple editions of the Diagnostic and Statistical Manual and the International Classification of Diseases, as well as its definition within emerging ontologies.

Results: Two independent roots of the ICD construct emerged: (a) the interest in behavioral excess as expressed in encyclopedic compilations (18th century) and (b) the juridical debate on disruptive conduct and responsibility (19th-20th centuries). These roots underlie the repeated taxonomic remodeling observed throughout the 20th and 21st centuries and three critical issues persisting in both clinical practice and research. First, the number of ICDs keeps increasing across the spectrum of human behaviors, disregarding common pathogenetic and phenomenological grounds. Secondly, ICDs substantially overlap with other mental conditions. Impulsivity is often neglected as a minor inconvenience or side effect when co-occurring with major diagnoses (e.g. depression) and therefore inadequately managed. Finally, ICDs' definitions display an unsolved tension between being conceived as hobby, moral fault or pathological drive, which may be responsible for stigma and delayed intervention.

Conclusion: The reasons that made impulse control disorders (ICDs) difficult to define from their first conceptualization are the same reasons that now complicate taxonomic efforts and diagnosis. Tracing back ICDs' roots and criticalities can help to define a common and less ambiguous theoretical framework, which may also result in the demise of the ICD construct and a move towards more clearly defined and more useful ontologies.