Delusional disorder and delusions: is there a risk of violence in social interactions about the core symptom?

Abstract

Delusional disorders are rare, but psychoses with prominent and persistent delusions are less so. A small but significant association between psychosis and violence is often mediated by delusions in such illnesses. Traditionally, delusions have been viewed as "incorrigible", but there is evidence that they change over time. During development of a scale for measuring delusions, it was found that people who acted violently on their "most important" delusion were more likely to have modified that belief after a mild form of challenge to it. When cognitive-behaviour therapy (CBT) is used for schizophrenia, attempts to modify psychotic symptoms are generally included. Could studies of CBT provide further information about possible risks of social interactions about delusions?In the UK, 2000 people with schizophrenia have been in randomized controlled trials of CBT with a goal of symptom modification. These studies were examined for evidence of violence during the treatment. There was none. Given the period prevalence of violence among people with psychosis, this is surprising. In these studies, however, both challenge to delusions and change in them was minimal and in the context of a safe clinical relationship. Challenge to delusions may, however, occur in a variety of social situations. There are no systematic data on lay challenge to them, but it seems likely that some in the sufferer's social circle will do so vigorously. Relatives, friends, and acquaintances are the people most vulnerable to the most serious violence by someone with psychosis. Study of how people interact in these circumstances and whether their interactions are relevant to modification of delusions would be worthwhile. Could those close to a sufferer learn skills for responding to such pathological beliefs that could be protective against violence, perhaps derived from the principles of CBT?