Neighborhood-Level Predictors of Age-at-First-Diagnosis of Psychotic Disorders: A Swedish Register-Based Cohort Study.

The relationship between neighborhood-level factors and the incidence of psychotic disorders is well established. However, it is unclear whether neighborhood characteristics are also associated with age-at-first-diagnosis of these disorders. We used linked Swedish register data to identify a cohort of persons first diagnosed with an ICD-10 non-affective or affective psychotic disorder (F20-33) between 1997 and 2016. Using multilevel mixed-effect linear modelling, we investigated whether neighborhood deprivation and population density at birth were associated with age-at-first diagnosis of a psychotic disorder. Our final cohort included 13,440 individuals, with a median age-at-first-diagnosis of 21.8 years for women (interquartile range [IQR]: 19.0-25.5) and 22.9 years for men (IQR: 20.1-26.1; P < .0001). In an unadjusted model, we found no evidence of an association between neighborhood deprivation and age-at-first-diagnosis of psychotic disorder (P = .07). However, after multivariable adjustment, age-at-first-diagnosis increased by .13 years (95% CI: .05 to .21; P = .002) for a one standard deviation increase in neighborhood deprivation. This was equivalent to a later diagnosis of 47 days (95% CI: 18 to 77). We found no evidence of a different relationship for non-affective versus affective psychoses [LRT χ 2(1) = .14; P = .71]. Population density was not associated with age-at-first-diagnosis in unadjusted (P = .81) or adjusted (P = .85) models. Later age-at-first-diagnosis for individuals born in more deprived neighborhoods suggests structural barriers in accessing equitable psychiatric care.