Teens living in major cities in England and Wales are more than 40 percent more likely to report psychotic experiences (hearing voices, paranoia, delusions) compared to teens living in rural areas, according to a new study published in the journal Schizophrenia Bulletin.
Researchers from King’s College London and Duke University found that neighborhood conditions and crime were strong contributing factors. Among adolescents who had grown up in the worst neighborhoods and had also been victims of violent crimes, 62 percent reported having some type of psychotic experience.
This high rate of psychotic experiences was almost three times greater than those living in more favorable neighborhood conditions who had not experienced violent crime (21 percent).
“As increasing numbers of young people around the world are living in cities, there is a growing need to improve our understanding of how both built and social features of urban settings are supporting and challenging young people’s mental health,” said Professor Candice Odgers, senior author from Duke University.
Adolescence is a particularly vulnerable time for mental health — around 70 percent of adults with mental health problems had their first episodes during adolescence.
In fact, up to one in three young people at some point have had a psychotic experience, and these individuals are at greater risk for other mental health disorders, schizophrenia, and suicide attempts. Yet little is known about the potential impact of social surroundings — such as living in a city — on adolescent expressions of psychosis.
In a previous study, the research team found higher rates of psychotic symptoms among children living in cities, but this new study is the first to examine the effects of city life on psychotic experiences during adolescence.
“Our study suggests that the effects of city life on psychotic experiences are not limited to childhood but continue into late adolescence, which is one of the peak ages at which clinical psychotic disorders are typically diagnosed,” said Jo Newbury, first author of the study, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London.
For the new study, researchers interviewed more than 2,000 British 18-year-olds about psychotic experiences since the age of 12. The authors note that they were only looking for subclinical experiences of psychosis, rather than evidence of a diagnosable, clinical disorder.
Youth were considered to have psychotic experiences if they reported at least one out of thirteen potential experiences including, for example, that they heard voices that others could not, believed they were being spied on, or their food was being poisoned.
Levels of “urbanicity” were assigned to each participant based on their post code, using data from the Office of National Statistics. Neighborhood social factors, such as trust, support, and cooperation between neighbors, and signs of threat like muggings, assaults, and vandalism were measured through surveys of over 5,000 immediate neighbors of the participants.
Finally, personal victimization by violent crime was assessed through interviews with the participants themselves.
The findings show that young people raised in urban versus rural neighborhoods were significantly more likely to have psychotic experiences, and this association remained significant after considering a range of other factors, including family socioeconomic status, family psychiatric history, and cannabis use.
Among those who lived in the largest, most densely populated cities, 34 percent subsequently reported psychotic experiences between age 12 and 18, compared to 24 percent of adolescents in rural settings.
Almost half of the association between city life and psychotic experiences was explained by adverse and threatening social characteristics of urban neighborhoods, including lack of trust and support between neighbors, and high levels of threat in the neighborhood.
The researchers suggest a number of reasons why living in the city could increase the risk for psychotic experiences, including a heightened biological response to stress, which could in turn disrupt the activity of dopamine in the brain. Excess dopamine is the best biological explanation researchers currently have for psychotic illnesses such as schizophrenia.
They also suggest that teens who grow up in threatening neighborhoods could develop maladaptive cognitive responses, such as hypervigilance (becoming excessively aware of potential threats) and attributing negative intentions to people, which might lead them to become paranoid about those around them.
“These findings highlight the importance of early, preventative strategies for reducing psychosis risk and suggests that adolescents living in threatening neighborhoods within cities should be made a priority,” said Dr. Helen Fisher, senior author from IoPPN at King’s College London.
“If we intervene early enough, for example by offering psychological therapies and support to help them cope better with stressful experiences, we could reduce young people’s risk for developing psychosis and other mental health problems further down the line.”
Source: King’s College London