When Clinical Concepts Creep
by Dr. Drew Dixon Karris
The phrase “concept creep” refers to the gradual broadening of psychological and harm-related concepts to include a broader range of experiences and behaviors. University of Melbourne psychology professor Nick Haslam initially described the phenomenon in concepts of trauma, abuse, bullying, addiction, prejudice, and mental disorders (Haslam et al., American Psychologist, 2021).
Concept creep can occur in two primary ways. Horizontal expansion occurs when a concept gets applied to new contexts or categories of experience. For example, the concept of bullying may be extended beyond school settings to workplaces or online environments. Vertical expansion occurs when the threshold for applying a concept becomes less rigid, such that experiences once seen as less severe get included within the same category. Trauma is frequently discussed as an example of this.
Concept creep is not inherently good or bad. Broadening the definitions of words may have the positive effect of increasing recognition of experiences that were previously minimized, reducing stigma, and improving access to care. On the other hand, excessive expansion may reduce conceptual precision and blur distinctions between normative distress and psychopathology (Xiao et al., PLOS ONE, 2023).
Two frequently discussed examples are the terms “narcissist” and “autism.”
“Narcissist”
The term “narcissist” is commonly used outside clinical settings to describe people perceived as being selfish, controlling, or lacking empathy. This definition differs significantly from the clinical meaning of narcissism.
Narcissistic traits exist on a dimensional spectrum and are present to varying degrees in quite a bit of the general population. Narcissistic personality disorder, however, describes a more specific and persistent pattern involving features such as grandiosity, a need for admiration, interpersonal difficulties, and impaired empathy, with associated impairment (American Psychiatric Association, DSM-5-TR, 2022).
A 2026 study examined how members of the general public applied the concept of narcissism to descriptions of behavior. Approximately 25% of participants classified ordinary behavior and traits as narcissistic. Participants who had broad definitions of narcissism also reported encountering more narcissistic individuals in their daily lives. Participants with training or experience in psychology tended to use narrower definitions (Hengartner, Eymir, and Haslam, Acta Psychologica, 2026).
This broadening seems to have occurred primarily in popular usage rather than through formal diagnostic criteria. A review of changes across diagnostic manuals found little evidence that the criteria for narcissistic personality disorder had become progressively broader (Fabiano and Haslam, Clinical Psychology Review, 2020).
“Autism”
Autism is a more complicated example because some of the broadening has occurred within formal diagnostic systems as well as within public discourse. Across diagnostic manuals, the conceptualization of autism has changed substantially. Previously separate diagnostic categories were consolidated under autism spectrum disorder. Fabiano and Haslam (2020) identified autism as one of the diagnostic categories in which there was evidence of expansion at the level of formal criteria.
More recent discussion has focused on whether continued expansion may create problems with diagnostic specificity. Some authors have argued that increasingly broad applications of the diagnosis may reduce the clarity of the category or contribute to meaningful differences between individuals diagnosed in childhood and those identified later in life (Frith, Psychological Medicine, 2026). Other researchers have raised concerns about the use of screening measures as diagnostic tools, differences in diagnostic practices, and the possibility that the pressure to offer healthcare services influences how diagnostic thresholds are applied (Liao and Fombonne, JAMA Pediatrics, 2026; Silva et al., Cadernos de Saúde Pública, 2025).
It is important to acknowledge that broader recognition of autism has addressed underdiagnosis in groups that were historically less likely to be identified. Many autistic adults, particularly those without intellectual disability or with less stereotypical presentations, were not recognized in childhood and have received diagnoses only later in life (Lai and Baron-Cohen, Lancet Psychiatry, 2015).
Why does conceptual precision matter?
Clinical concepts are intended to organize patterns of symptoms, behavior, impairment, and experience. When these terms enter everyday language, their meanings often become less precise, which can obscure distinctions that are important for assessment and treatment.
For example, traits associated with autism, personality pathology, trauma responses, anxiety, or normative interpersonal conflict may overlap on the surface while differing substantially in developmental history, function, persistence, context, and underlying mechanisms. Applying a familiar label based on isolated behaviors can create an inaccurate impression of what is occurring.
The implication of conceptual creeping is not to discourage the use of clinical language by non-professionals, or to dismiss individuals who recognize themselves in diagnostic descriptors. The implication is to be aware of the phenomenon and work to maintain a distinction between colloquial and clinical use of specific language.
References
Fabiano, F., & Haslam, N. (2020). Diagnostic inflation in the DSM: A meta-analysis of changes in the stringency of psychiatric diagnosis from DSM-III to DSM-5. Clinical Psychology Review, 80, Article 101889. https://doi.org/10.1016/j.cpr.2020.101889
Frith, U. (2026). Autism spectrum disorder: Has it lost its meaning and is it leading to misdiagnosis? Psychological Medicine, 56, Article e240. https://doi.org/10.1017/S0033291726105376
Haslam, N., Vylomova, E., Zyphur, M., & Kashima, Y. (2021). The cultural dynamics of concept creep. American Psychologist, 76(6), 1013–1026. https://doi.org/10.1037/amp0000847
Hengartner, M. P., Eymir, A., & Haslam, N. (2026). Expanded definitions of psychopathology: Exploring concept creep in narcissistic personality disorder. Acta Psychologica, 264, Article 106604. https://doi.org/10.1016/j.actpsy.2026.106604
Liao, L., & Fombonne, E. (2026). Autism overdiagnosis and its harmful effects. JAMA Pediatrics, 180(7), 711–712. https://doi.org/10.1001/jamapediatrics.2026.0400
Silva, R. A. da, Queiroz, S. do P. O., & Silva, F. P. da. (2026). Transtorno do espectro autista na atualidade: Reflexões críticas sobre o hiperdiagnóstico [Autism spectrum disorder today: Critical reflections on hyperdiagnosis].
Cadernos de Saúde Pública, 42, Article e00140725. https://doi.org/10.1590/0102-311XPT140725
Xiao, Y., Baes, N., Vylomova, E., & Haslam, N. (2023). Have the concepts of ‘anxiety’ and ‘depression’ been normalized or pathologized? A corpus study of historical semantic change. PLOS ONE, 18(6), Article e0288027. https://doi.org/10.1371/journal.pone.0288027
