Hospital service utilisation of people previously hospitalised with different subtypes of psychotic disorder: A record linkage study.

Little research has examined the physical and mental comorbidities, and health service use patterns, of people diagnosed with psychotic disorder subtypes other than schizophrenia spectrum disorders. This study aims to examine the physical and mental comorbidities, and subsequent hospital service use patterns, of individuals previously hospitalised with various psychotic disorder subtypes using linked health service data. We included individuals hospitalised with a psychotic disorder in New South Wales, Australia, between 1 July 2002 and 31 December 2014 (N = 63,110). We examined the demographic profile of the cohort and rates of subsequent acute hospital care and ambulatory mental health service use. We compared the rates of subsequent hospital admissions, emergency department presentations and ambulatory mental health treatment days of people hospitalised with different psychotic disorder subtypes to people hospitalised with schizophrenia spectrum disorders using Poisson regression. People most recently hospitalised with mood/affective disorders and psychotic symptoms had a higher rate of subsequent hospital admissions than those most recently hospitalised with schizophrenia spectrum and delusional disorders (adjusted incident rate ratio = 1.06; 95% confidence interval = [1.02, 1.10]), while people most recently hospitalised with drug-induced and other organic (adjusted incident rate ratio = 1.19; 95% confidence interval = [1.12, 1.27]) and acute psychotic disorders (adjusted incident rate ratio = 1.10; 95% confidence interval = [1.03, 1.18]) had more subsequent emergency department presentations than those most recently hospitalised with schizophrenia spectrum and delusional disorders. All three groups had fewer subsequent mental health ambulatory days than those most recently hospitalised with schizophrenia spectrum and delusional disorders (adjusted incident rate ratios = 0.85-0.91). The health profiles and subsequent hospital service use patterns of people previously hospitalised with different psychotic disorder subtypes are heterogeneous, and research is needed to develop targeted health policies to meet their specific health needs.