First-contact incidence of psychosis in north-eastern Italy: influence of age, gender, immigration and socioeconomic deprivation

Background Considerable variations in the incidence of psychosis have been observed across countries, in terms of age, gender, immigration status, urbanicity and socioeconomic deprivation. Aims To evaluate the incidence rate of first-episode psychosis in a large area of north-eastern Italy and the distribution of the above-mentioned risk factors in individuals with psychoses. Method Epidemiologically based survey. Over a 3-year period individuals with psychosis on first contact with services were identified and diagnosed according to ICD-10 criteria. Results In total, 558 individuals with first-episode psychosis were identified during 3077 555 person-years at risk. The annual incidence rate per 100000 was 18.1 for all psychoses, 14.3 for non-affective psychoses and 3.8 for affective psychoses. The rate for all psychoses was higher in young people aged 20-29 (incidence rate ratio (IRR)=4.18, 95% CI 2.77-6.30), immigrants (IRR=226, 95% CI 1.85-2.75) and those living in the most deprived areas (IRR=2.09, 95% CI 1.54-2.85). Conclusions The incidence rate in our study area was lower than that found in other European and North American studies and provides new insights into the factors that may increase and/ or decrease risk for developing psychosis.