Association between non-compliance with psychiatric treatment and non-psychiatric service utilization and costs in patients with schizophrenia and related disorders

BACKGROUND: The relationship between medication non-compliance in patients with schizophrenia and related disorders, and increased psychiatric service utilization and costs are well documented; however, non-psychiatric service utilization and costs are not. Therefore, we investigated the association of non-compliance with psychiatric treatment and the utilization and costs of non-psychiatric services. METHODS: Data on South Korean individuals with a lifetime diagnosis of schizophrenia or a related disorder, who were treated in a psychiatric clinic at least twice during 2011, were selected among national data collected for the Health Insurance Review and Assessment Service-National Patients Sample between January 1, 2011 and December 31, 2011. The sample was divided into two overlapping groups with two different classifications of patterns of medication prescription refills: (1) adherent versus non-adherent group, and (2) persistent versus non-persistent group. A matching method was used to remove the effects of different follow-up durations and insurance system on medical service utilization and costs. The final sample for analysis consisted of data from 5,548 individuals in the adherent versus non-adherent group and 3,912 in the persistent versus non-persistent group. Comparisons of the psychiatric and non-psychiatric service utilizations were made between the groups. RESULTS: The number of psychiatric service utilizations were significantly lower in the non-adherent than the adherent group. They were also significantly lower in the non-persistent group than the persistent group. The number of non-psychiatric service utilizations was significantly higher in the non-adherent group. They were also significantly higher in the non-persistent group than the persistent group. All psychiatric costs per person during the study period were lower in the non-adherent than the adherent group, and lower in the non-persistent than the persistent group. All non-psychiatric costs per person were higher in the non-adherent than the adherent group, and higher in the non-persistent than the persistent group. CONCLUSION: Non-adherence to psychiatric treatment by patients with schizophrenia and related disorders was associated with higher medical service utilization and increased personal and societal medical costs. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12888-016-1156-3) contains supplementary material, which is available to authorized users.