The psychological effect of an urban environment on individuals with persecutory delusions: The Camberwell walk study

Background: Epidemiological studies have found that individuals who live in urban areas are at increased risk of developing psychosis. However it is unknown whether exposure to urban environments exacerbates psychotic symptoms in people who have a diagnosed psychotic disorder. The aim of the study was to examine the psychological and clinical effects of exposure to one specific deprived urban environment on individuals with persecutory delusions. It was predicted that the urban environment would affect emotional and reasoning processes highlighted in a cognitive model of persecutory delusions and would increase paranoia. Method: Thirty patients with persecutory delusions were randomised to exposure to a deprived urban environment or to a brief mindfulness relaxation task. After exposure, assessments of symptoms, reasoning, and affective processes were taken. Thirty matched non-clinical participants also completed the study measures to enable interpretation of the test scores. Results: In individuals with persecutory delusions, exposure to the urban environment, rather than participation in a mindfulness task, increased levels of anxiety, negative beliefs about others and jumping to conclusions. It also increased paranoia. The individuals with persecutory delusions scored significantly differently from the non-clinical group on all measures. Conclusions: For individuals with psychosis, spending time in an urban environment makes them think more negatively about other people and increases anxiety and the jumping to conclusions reasoning bias. Their paranoia is also increased. A number of processes hypothesised in cognitive models to lead to paranoid thoughts are exacerbated by a deprived urban environment. Further research is needed to clarify which aspects of urban environments cause the negative effects. Methodological challenges in the research area are raised. (C) 2007 Elsevier B.V. All rights reserved.