Veterans Affairs Serious Mental Illness Patients: Differences in High-Intensity Service Use by Personality Disorder Status

Individuals with serious mental illnesses (SMI) or personality disorders (PD) have complex treatment needs and are at risk of adverse outcomes. Yet, little is known about the impact of comorbid SMI and PD on risk factors. This study used the Veterans Health Administration (VHA)'s corporate data warehouse (CDW) to assess the differences between those with and without a comorbid PD, as well as the prevalence and impact of PD diagnoses on high-intensity/emergency service utilization in VHA patients with a SMI diagnosis (schizophrenia spectrum disorders and bipolar spectrum disorders). In fiscal year 2018, 163,904 VHA patients had encounters that listed SMI diagnoses, including 9,216 patients who had encounters that listed PD diagnoses. Bivariate analyses and logistic regression were used to compare group characteristics and determine whether a PD diagnosis was associated with utilization of high-intensity care services. The SMI with no PD and SMI with comorbid PD (SMI-PD) groups differed in terms of demographic, medication, clinical, and service utilization characteristics, including that the SMI-PD group was 5.25 times more likely to have documented suicide risk and 4.73 times more likely to have documented behavioral risk. After controlling for multiple patient characteristics, patients in the SMI-PD group were 1.35 times more likely to have some emergency department (ED) utilization and 1.94 times more likely to have some inpatient mental health use. Having a diagnosed comorbid PD was associated with increased prevalence of medical and psychiatric problems. Findings suggest that patients with comorbid PDs have particularly high-treatment needs and may benefit from assessment of, and adapted treatments for, PDs. Impact Statement In this evaluation, patients who had both a serious mental illness (SMI) and a comorbid personality disorder (PD) diagnosis, compared to patients with SMI but no PD, had higher rates of emergency department and inpatient mental health use, and were more likely to have been identified as being at elevated suicide or aggression risk. These findings support earlier findings, and yet, there has not been much work looking at how having a comorbid PD might impact the treatment needs of those with a SMI. This evaluation demonstrates a clear need for more specialized care for this high-risk group, patients with an SMI and comorbid PD diagnosis.