URBAN UPBRINGING INFLUENCES RESPONSE TO SOCIAL FEEDBACK

Background: Growing up in an urban environment is associated with a higher incidence of schizophrenia. The effects of urbanicity seem particularly pronounced during development. It has been hypothesized that urbanicity could be a proxy for social stress, which might account for disturbed social interactions and trust in the disorder. Yet, how urbanicity affects trust and the dynamics of social interactions in schizophrenia has not been investigated experimentally. Previous studies have suggested that a key feature of disturbed trust in schizophrenia is a lack of sensitivity to the behavior of others. We hypothesized that higher exposure to urban environment during development is associated with a greater insensitivity to social signals.

Results: Patients showed lower basic trust than controls, but mean investments in both the cooperative and unfair condition did not differ between groups. Patients grew up in marginally more urban environments (P = .07). Urbanicity was not associated with basic trust. In the cooperative condition, there was a significant interaction between group, trial number, and urbanicity (P = .002). Controls adjusted their levels of trust during interactions with positive and negative feedback, regardless of urbanicity. Patients however adjusted their investments less with increasing urbanicity: in the highest urbanicity group, patients made no behavioral adjustments over trials, but the other urbanicity levels were associated with significant increases in trust. In the unfair condition, the interaction reached trend level (P = .086); however, a similar pattern of effects emerged whereby higher urbanicity correlated with less decline in trust, thus with less adaptive behavior.

Conclusion: High levels of urbanicity in psychosis patients but not in controls are associated with increasing insensitivity to the behavior of others, particularly during cooperation. This insensitivity to others could aggravate social dysfunction and might be driven by prolonged social stress exposure and a desensitized emotional and reward systems in the brain. Future (neuroimaging) studies will be necessary to investigate the mechanisms underlying the influence of urbanicity on trust in order to corroborate our findings.

Methods: We used 2 multiround trust games to measure the trust during repeated social interactions and basic trust toward unknown others. Twenty-four adolescents with nonaffective psychosis and 24 age-matched healthy controls (mean age 19.6, SD = 1.6) played the 20-round trust games with a preprogrammed cooperative (returning more) and unfair partner (returning less than invested), to probe under which circumstances urbanicity affects reactions to social behavior. Urbanicity was defined as the density of addresses per km2, with 5 levels from rural to very urban. Mean urbanicity exposure over 0–15 years of age was used. All analyses (multilevel regressions) were controlled for IQ and gender.