Cumulative social disadvantage and psychosis: findings from a southern Italy case-control study

Aim: There are consistent evidence suggesting that psychotic disorders are associated to social disadvantage and isolation in adulthood, and research suggested that they these are not simply a consequence of the functional impairment related to onset of the disease (Stilo et al., 2013; Morgan et al., 2008). To date only a few studies have investigated the impact of social risk factors on psychosis in Italy. This study aimed to replicate existing findings in a case-control sample from Southern Italy. Methods: 134 individuals presenting for the first time to mental health services of Palermo (Italy) with an ICD 10 diagnosis of psychosis and 175 population controls from Palermo (Italy) were enrolled, as part of the Sicilian Genetics and Psychosis study. Information about current social indicators were collected by the modified version of the Medical Research Council (MRC) socio-demographic scale. Results: Cases and controls were different in terms of gender, age, family history for psychotic disorders, and education achievement. Unemployment, no relationship, and lack of close confidants were independently associated with psychotic disorders, and these associations were still significant after adjusting for confounders. However, in contrast with previous studies from Northern Europe, cases were more likely to live with their parents or other relatives, rather than alone. A cumulative index of social disadvantage was computed using unemployment, no relationship, and lack of close confidants (range 0-3). Controlling for gender, age, education level and family history of psychosis, there was evidence of an effect of increased risk for psychosis for individuals exposed to ≥ 2markers of social disadvantage. Conclusion:   Unemployment, being single, and lack of close friends were significantly related with psychosis, while living alone was not. Moreover, in contrast with previous studies that found evidence of dose-response effect, in this sample individuals exposed to more than 2 markers of social disadvantage showed a five-fold increase in the odds for psychosis, suggesting the possibility of a threshold effect.