B3309 - Understanding the mechanisms linking the urban environment to psychotic experiences across the lifespan - 21/05/2019

B number: 
B3309
Principal applicant name: 
Joanne Newbury | King's College London and University of Bristol (United Kingdom)
Co-applicants: 
Title of project: 
Understanding the mechanisms linking the urban environment to psychotic experiences across the lifespan
Proposal summary: 

Individuals who are raised in urban (versus rural) settings are around twice as likely to develop a psychotic disorder in adulthood. This association has now been replicated for subclinical psychotic experiences during childhood and adulthood (e.g., hearing voices, extreme paranoia). These symptoms lie on a continuum with clinical psychosis and therefore provide a useful marker to explore the urbanicity-psychosis association in the general population. Given that 70% of the world’s population will live in urban areas by 2050, it is essential that we uncover the pathways linking cities and psychosis so that we can inform intervention efforts.

Research supports a role of neighbourhood social factors correlated with urbanicity in the aetiology of psychotic experiences, such as neighbourhood disorder and social fragmentation (i.e., weak connections between individuals in a community). In addition, emerging research suggests that urban residents have a higher genetic risk for schizophrenia, meaning that the urbanicity-psychosis association could be partly confounded by genes.

However, very little is currently known about the potential role of air pollution in the link between cities and psychosis. Air pollution is the world's biggest environmental health problem, and is particularly problematic in cities. Recent cross-sectional research has provided the first evidence linking air pollution to psychotic experiences among teenagers.

However, longitudinal research into the link between air pollution and psychotic experiences is needed to establish the temporal nature of associations. In addition, neighbourhood social exposures are highly correlated with air pollution (i.e., the most deprived neighbourhoods also tend to be the most polluted). The interplay between neighbourhood social conditions and air pollution (i.e., confounding versus interaction) in relation to psychotic experiences is not known. Furthermore, though influences on inflammatory and cognitive processes are the most commonly suggested mechanisms linking urban exposures to psychosis, very few studies have directly tested these mechanisms.

This project will examine 1) the longitudinal associations of air pollution exposure from birth to age 15 with psychotic experiences in childhood and adolescence, 2) the interplay between neighbourhood social characteristics (neighbourhood disorder and social fragmentation) and air pollution in the emergence of psychotic experiences, and 3) potential biopsychological mechanisms linking urban neighbourhood exposures with psychotic experiences, including inflammation and cognition.

Impact of research: 
This research will serve a range of stakeholders, including researchers, industry, policymakers, and the general public. Air pollution is a known cause of physical disease, but very little is known about the impact of air pollution on mental health problems. My research will contribute to the evidence base on air pollution and mental health, which is essential for policymakers to make the economic case for tightening air pollution restrictions. Though a major global challenge, urban expansion nevertheless provides a unique opportunity for promoting healthy urban design. My research will also be useful to industry and policymakers to provide evidence on targets in the urban environment that could be modified to improve mental health. By identifying modifiable targets in the urban environment, this research has the strong potential to improve the mental health of urban residents now and for years to come. My plan for maximising impact of the findings is as follows: 1) I expect that the research proposed will lead directly to at least four publications in highly regarded journals with a broad readership. 2) I will disseminate findings via oral presentations at six international psychiatry/epidemiology conferences that attract a wide audience such as MQ Mental Health Science Meeting. 3) I will liaise with press teams such as the Science Media Centre to maximise the impact of the findings through press releases and press briefings. 4) I will ensure that findings are clearly presented to the public by preparing blogs and podcasts, and by participating in interactive open workshops and talks. 5) I will share my findings with policymakers by holding a policy lab with support from Policy Bristol.
Date proposal received: 
Wednesday, 8 May, 2019
Date proposal approved: 
Thursday, 9 May, 2019
Keywords: 
Epidemiology, Mental health, Statistical methods, Environment - enviromental exposure, pollution