O8.5. SCHIZOPHRENIA AND BIPOLAR DISORDER DIAGNOSIS PATTERNS: REAL-WORLD EVIDENCE FROM US CLAIMS DATABASES

Abstract

Background: Schizophrenia and bipolar disorder (BD) are typically understood as separate and non-concurrent psychiatric disorders both in the clinical setting and in the DSM-V and ICD-10 classification systems. However, patients may experience both mood and schizophrenia symptoms simultaneously. Several studies have shown overlap between schizophrenia and BD symptoms, which may lead to diagnostic confusion. Additionally, molecular studies have confirmed that schizophrenia and BD share susceptibility genes. This study explored diagnosis patterns of patients with schizophrenia and/or type I bipolar disorder (BD-I) diagnoses in a real-world setting. Method(s): This was a retrospective cohort study using Truven MarketScan Commercial, Medicaid, and Medicare Supplemental databases from the study period 01/01/2012 and 06/30/2016. Patients were considered to have a diagnosis of schizophrenia if 1 inpatient claim or 2 outpatient claims for schizophrenia were identified within a selected identification period (01/01/2013 and 06/30/2015). BD-I was defined in an analogous way, and the following five mutually exclusive cohorts were defined: 1) schizophrenia (SCZ) alone (cohort I): newly diagnosed with schizophrenia alone (e.g., met the claims-based diagnostic criteria for schizophrenia, but not for BD-I), 2) BD-SCZ (cohort II): met BD-I criteria only in the year prior to meeting the schizophrenia criteria, 3) SCZ-BD (cohort III): met schizophrenia criteria only in the year prior to, or on the same day as, meeting BD-I criteria, 4) BD-SCZ-BD (cohort IV) met BD-I criteria both in the year before and the year after meeting the schizophrenia criteria, and 5) BD alone (cohort V): newly diagnosed with BD-I alone (e.g., met the claims-based diagnostic criteria for BD-I, but not for schizophrenia). Descriptive statistics are reported for all cohorts. Result(s): Of the 63,725 patients in the final analytic sample, 11.5% (n=7,336) had schizophrenia alone (cohort I), 7.7% (n=4,909) had a dual diagnosis (cohorts II-IV), and 80.8% (n=51,480) had BD-I alone (cohort V). The dual diagnosis patients included 1.0% (n=615) with BD-SCZ (cohort II), 2.8% (n=1,794) with SCZ-BD (cohort III), and 3.9% (n=2,500) with BD-SCZ-BD (cohort IV). Patients with different diagnosis patterns significantly differed in age, gender, and insurance type (p