Abstract
Delusion has long stood as a central symptom in psychiatric diagnosis; however, its definition remains elusive. To begin with, the present article offers a brief review of historical and contemporary efforts to conceptualize delusions, highlighting contributions from pre-modern cultural observations to seminal works by psychiatrists such as Jaspers, K. Schneider, and M. Spitzer. Despite these endeavors, the definition of delusion continues to rely on folk-psychological and commonsense judgments, introducing a degree of indeterminacy. Focusing specifically on persecutory delusions and analogous anomalous judgments, the article then examines the challenges in distinguishing delusional from non-delusional thoughts, particularly within varying cultural contexts. This leads to an exploration of how sociocultural conditions influence the formation and interpretation of delusions, drawing upon studies by Japanese psychopathologists. These investigations underscore the importance of cautious and detailed sociocultural consideration in the analysis of delusional phenomena. In conclusion, the article argues that in our increasingly interconnected world, where sociocultural boundaries are fluid, incorporating cultural sensitivity into the understanding and diagnosis of delusions is not only beneficial but essential.

Abstract
Delusions are often expressed not merely as beliefs but as claims of knowledge about the external or intersubjective world. Traditional epistemological approaches evaluate such claims in terms of epistemic justification and therefore regard delusions as illegitimate. However, this perspective risks unproductive clinical disputes, since common-sense beliefs themselves frequently lack explicit justification and rest on shared but ultimately groundless assumptions. This paper proposes an alternative framework based on Nozick’s tracking theory of knowledge. From this externalist perspective, knowledge does not require internal access to justification but depends on whether beliefs are sensitive to relevant counterfactual variations. Delusions can thus be characterized not primarily by their lack of justification, but by their fixity: they remain unchanged across nearby possible worlds in which the relevant facts differ. We argue that a tracking theory–based approach shifts clinical attention from epistemic legitimacy to counterfactual sensitivity, facilitating dialogue without directly challenging core delusional beliefs. A clinical case of erotomania illustrates this approach, and its applicability and limits with respect to cultural delusions are briefly discussed.

Abstract
The current definition of delusion in psychopathology implies an inherent culturalist approach: a delusion is a fixed belief which is not in keeping with the world view shared by the patient’s sociocultural group of reference. This essential characteristic, however, doesn’t help the clinician when it comes to making a judgement on the sanity or the insanity of a seemingly delusional belief held by a person, which is entirely in keeping with the beliefs of the majority of the people within the same society, or at least a considerable number of them. The concept of cultural delusion can be helpful in such scenarios. Cultural delusions are defined as notions, views, convictions or even “knowledge” (pseudo-knowledge) held by a sociocultural group and, as a result, they are perceived as “normal’, “true”, “valid” and self-evident realities. Just like in individual delusions, the morbidity of cultural delusions lies within the resulting altered relationship with the rest of the world and reality, rather than on their factually erroneous content. Cultural delusions are based on a shared world view, therefore they are not private or idiosyncratic beliefs held by a visibly dysfunctional individual. In this sense, they defy the commonly held notion that a delusional reality necessarily locks the person in a private world, the validity of which he/she is the only one to acknowledge. By the same token, the potential for harm of cultural delusions is incomparably higher than that of individual delusions. Racism is a good example of such delusional beliefs, and conceptualising racism as a cultural delusion can be a useful approach to unveil its dysfunctional nature from a psychopathological perspective. This article intends to offer a preliminary and tentative interpretation of racism as a cultural delusion and a clinical vignette will be presented, illustrating one of the many forms in which racism reveals its cultural delusional nature in psychotherapeutic work.

Abstract
This paper proposes a psycho-cultural pathway linking (i) ambivalent Euro-American representations of the racialised ‘Other’, (ii) a culturally induced form of splitting, and (iii) culturally shared delusional formations. Drawing on cultural psychiatric work that frames ‘cultural delusions’ as group-endorsed, ego-syntonic, highly implausible and socially incorrigible beliefs that constrain individual and collective development, we treat white supremacism as delusion-like belief. We introduce the concept of culturally induced splitting to describe how socio-cultural-institutional and media ecologies can distribute ambivalence into polarised stereotypes (for example, “good refugee” versus “bad migrant”), allowing benevolence and hostility to co-exist without integration. Digital epistemic dynamics (epistemic bubbles and echo chambers) are considered as amplifiers of splitting and of preference falsification. A brief field vignette from qualitative work in Italian mental-health services illustrates how oscillating representations operate within helping institutions. We conclude with implications for cultural psychotherapy and research: interventions may need to focus on making ambivalence thinkable, increasing institutional reflexivity, and addressing echo-chamber dynamics rather than relying solely on factual dispute.