May 30, 2017


Does living in a city make you psychotic? (SHARON BEGLEY, MAY 30, 2017, STAT)

For a study published last week, researchers interviewed 2,063 British twins (some identical, some not) at age 18 about "psychotic experiences" they'd had since age 12 -- such as feeling paranoid, hearing voices, worrying their food might be poisoned, and having "unusual or frightening" thoughts. Among those who lived in the most densely populated large cities, 34 percent reported such experiences; 24 percent of adolescents in rural areas did.

The twins are part of a long-running study that has followed them from birth in 1994-95, so the researchers-- led by Helen Fisher of King's College London and Candice Odgers of Duke University -- also knew the teens' family income, parents' education, where they lived, and more. Conclusion: 18-year-olds raised in big cities were 67 percent more likely to have had psychotic experiences, the researchers reported in Schizophrenia Bulletin.

They then used standard statistics tools to account for possible psychosis-related factors other than cities per se. Cities have more people who are poor and uneducated, which are risk factors for schizophrenia and other forms of psychosis, so they controlled for socioeconomic status. Family psychiatric history raises the risk of an individual's developing psychosis, and since there is some evidence that people with mental illness move to cities, which have more treatment facilities, the researchers controlled for this, too. They also controlled for drug use, some forms of which are more common in urban than rural areas. These calculations brought the extra risk of psychosis among urban teens down to 43 percent.

This study is far from the first to link city living to psychosis. In 2005, psychiatrists wrote that a higher prevalence of psychosis in cities "is one of the most consistent findings in schizophrenia research." A Swedish study and a Danish one even found that the longer someone lives in a city, the greater the risk of schizophrenia -- the sort of "dose response" that makes causality more likely.

Posted by at May 30, 2017 8:06 AM