Introduction
The disproportionate use of services by a subset of mental health service users, described here as “high use consumers” (HU), has been demonstrated in large, cross-sectional (Sullivan et al.
1993; Dhossche and Ghani
1998; Pasic et al.
2005; Hansen and Elliott
1993), longitudinal, (Saarento et al.
1998; Segal et al.
1998) and case control studies (Arfken et al.
2004; Silva et al.
2009) of emergency psychiatric care in several service systems in community and veterans samples (Hansen and Elliott
1993). Although the definitions of high utilization differ among studies, between 5 and 18% of mental health services users account for utilization of 27–63% of the services (Sullivan et al.
1993; Hansen and Elliott
1993; Dhossche and Ghani
1998; Saarento et al.
1998).
Disproportionately high use of mental health services by a small proportion of consumers is an issue that has challenged service delivery systems for decades. Several studies have investigated the sociodemographic and clinical variables associated with high service utilization in attempts to identify common characteristics that might inform the development of interventions to improve both delivery and quality of care (Surles and McGurrin
1987; Surber et al.
1987; Quinlivan et al.
1995; Sullivan et al.
1993; Witheridge et al.
1982). Few studies, however, have employed a theoretical framework to understand factors related to mental health service use, which could be helpful in designing program or system level interventions (Dhingra et al.
2010). According to a widely-used theory of service use, Andersen’s Behavioral Model of Health Service Use (Andersen and Newman
1973; Andersen
1995), the characteristics related to service use include more than need for services. Andersen and colleagues’ theory proposed that factors associated with health service use can be grouped into three categories: predisposing (characteristics of the individual, i.e., age, gender, race), enabling (system or structural factors, i.e., living arrangement and insurance status), and need (severity of illness) factors. Predisposing factors associated with high service utilization include male gender (Sullivan et al.
1993), younger age (Sullivan et al.
1993; Silva et al.
2009; Surles and McGurrin
1987), and non-Caucasian ethnicity (Sullivan et al.
1993; Havassy and Hopkin
1989). Enabling factors related to high utilization consist of single marital status (Sullivan et al.
1993), unemployment (Sullivan et al.
1993; Dhossche and Ghani
1998; Havassy and Hopkin
1989), homelessness (Dhossche and Ghani
1998; Pasic et al.
2005; Arfken et al.
2004), enrollment in a mental health plan (Pasic et al.
2005; Segal et al.
1998), and a less favorable pattern of service use (i.e., more hospitalizations and/or fewer outpatient visits) (Hansen and Elliott
1993; Pasic et al.
2005; Arfken et al.
2004; Silva et al.
2009). Need factors, such as a diagnosis of schizophrenia or other psychotic disorder (Sullivan et al.
1993; Dhossche and Ghani
1998; Hansen and Elliott
1993; Segal et al.
1998; Silva et al.
2009; Surles and McGurrin
1987), have consistently been shown to be associated with increase service utilization; whereas substance use has been found to increase utilization in some cases (Pasic et al.
2005; Surber et al.
1987), but not in others (Arfken et al.
2004). There is some suggestion in the literature that factors related to high service use may vary depending on chronicity (Pasic et al.
2005), i.e., high use of services for a single year versus several years. Knowledge of predisposing, enabling, and need characteristics associated with patterns of high service use, for a year or multiple years may inform mental health systems about the nature of the interventions that would be needed to optimize care for both the individual and the system.
Many interventions to address some combination of predisposing, enabling, and need factors have been developed to optimize service use for individuals who have relied heavily on acute and intensive services. These include Assertive Community Treatment, Intensive Case Management, and integrated care for those dually diagnosed with a psychiatric illness and substance abuse (Drake et al.
2001). Most of these interventions have focused on team-based, integrated approaches to address the multiple medical, psychiatric, and social issues common to the high use consumers. The more effective treatments have targeted all of the Andersen domains, but these interventions are few and resource intensive. Identifying important individual and system characteristics that are associated with high mental health service use is an essential step if effective and cost effective interventions are to be developed and implemented.
Not only is mental health service use influenced by characteristics of the individual, but also it is influenced by the structure of the service delivery system (Snowden
2007). In California, the mental health system has been undergoing substantial changes due to the enactment of the 2004 Mental Health Services Act (MHSA) (Cashin et al.
2008). This act provided resources to support the transformation of the mental health service system into one that is more recovery focused, reaches out to underserved and un-served populations, promotes innovation, and integrates services across multiple areas (e.g., health, housing, social assistance) if needed. These system transformation activities have the potential to influence the size and composition of the high use consumer population by altering the types of services available to existing mental health consumers and identifying new consumers who could benefit from mental health services. Given that the system transformation is currently in process, this paper utilizes data prior to the implementation of the MHSA, which corresponds to a more traditional service delivery system. These data provide a baseline from which to compare the influence of the MHSA system transformation on the high use consumer population following more extensive implementation and operation of the MHSA services in the coming years. Although the MHSA is specific to California, many local and regional mental health systems are considering transformation of service delivery so that information gleaned from changes in the San Diego County may guide the administrators and policy makers of other systems.
In summary, many studies have investigated the sociodemographic and clinical characteristics associated with access to mental health services, particularly emergency services. However, there is considerable methodological variation among the studies, including differences in the sample and study design, length of observation, definitions of high utilization, and types of services included. Inconsistency might also be furthered by different consumer subgroups based on use (Pasic et al.
2005). Finally, few studies have employed a theoretical framework to understand factors related to service use, which may assist in the identification of potential interventions to improve service use and quality of care. The purpose of the present study was to investigate the use of acute mental health services beyond emergency department use in a large sample of public mental health users on whom we had 4 years of data. We used a definition of HU that was consistent with previous reports of service utilization, and we examined use by subgroups of HU, specifically those using more than three acute services in 1 year or more than 1 year. These data provide a baseline of the size and composition of the high use consumer population prior the MHSA induced service transformations. We hypothesized that: (1) There is a small group of enrollees that use disproportionately more acute mental health services; and (2) Use of such services is related to predisposing factors of male gender, younger age, enabling factors of homelessness and outpatient service use, and need related factors, such as a diagnosis of schizophrenia and substance use; (3) Enabling and need factors differ between one time HUs and multiple-year HUs with multiple HUs having more barriers to service use and greater need.
Discussion
The majority of individuals receiving mental health services from a public system were not classified as HU, that is, as having used three or more acute (inpatient, crisis residential, EPU, or PERT) services in a year. About 20% of enrollees were classified as a HU in one or more years. The factors most strongly associated with being a HU versus a non-HU, controlling for other variables, were enabling factors of homelessness, medical insurance, and minimal use of outpatient services, as well as need factors, including a substance use disorder and a diagnosis of schizophrenia, bipolar or other psychotic disorder. Factors from all categories of the Andersen model—predisposing, enabling, and need—were significantly associated with a higher probability of ever having been classified as HU: younger age, female gender, homelessness, substance use disorder, medical insurance, and diagnosis of schizophrenia, bipolar disorder or other psychotic disorder. Several factors were significantly related to a lower likelihood of being a HU. These included Latino or “other” race, living in a board and care home or jail, having four or more outpatient visits per year, and having a diagnosis of other psychiatric disorder.
In the 1990s, Quinliven and others reported on the characteristics of high utilizers in San Diego County (Quinlivan et al.
1995; Quinlivan and McWhirter
1996). Using a definition of high utilization as three or more visits to the emergency department, they found that the majority of this group had the diagnosis of schizophrenia or schizoaffective disorder (68%), were more slightly more likely to be women (56%), were mostly Caucasian (57%) and were mostly young (88% were age 50 or less). Our sample had a higher proportion of persons over the age of 45 years but were otherwise similar to the group identified by Quinliven and colleagues in the early 1990s suggesting that the profile of a high use consumer has varied little over the decades.
Consistent with most previous reports in the literature, we found that a small proportion of individuals in the public mental health system were identified as high use consumers (Sullivan et al.
1993; Dhossche and Ghani
1998; Hansen and Elliott
1993; Saarento et al.
1998; Segal et al.
1998; Chaput and Lebel
2007). This finding is robust in that it is seen across many studies that examine different service systems and use different definitions of high service utilization. Therefore, identifying characteristics of such a group or groups of individuals is crucial to the development and implementation of solutions to optimize service use for the benefit of both the consumer and the service delivery system.
Many of the predisposing characteristics found in other studies to be associated with high mental health service utilization were observed to have significant relationships with being categorized as a HU in our study. As we predicted, and as others have reported (Sullivan et al.
1993; Silva et al.
2009), we found that younger age was associated with a higher likelihood of being classified as an ever HU when controlling for all other predisposing, enabling, and need factors. Female gender was significantly associated with an increased likelihood of being classified as an ever HU. Most previous research has failed to find a gender difference in service utilization (Arfken et al.
2004; Pasic et al.
2005; Chaput and Lebel
2007) or reported that male gender was related to high utilization (Sullivan et al.
1993; Young et al.
2005; Saarento et al.
1998).Our finding that female gender was associated with higher likelihood of being defined as a HU may reflect gender differences in treatment seeking. Other literature has reported that women are more likely to use mental health services (Mackenzie et al.
2006), but the relationship between gender and high utilization was not investigated. Alternatively, there could be gender differences in the systems for which men and women receive care. For example, men who are high use consumers of mental health services due to the severity of illness may be more likely to get services in the justice system if they exhibit dangerous behaviors toward others and are subsequently incarcerated.
Race/ethnicity has been found to be predictor of high service utilization in some (Sullivan et al.
1993; Young et al.
2005), but not all (Segal et al.
1998; Pasic et al.
2005) studies. In this study, we found that Latino race was associated with a decreased likelihood of being classified as an HU as was the “other” category that included Asian-American, Native-American, and other race. Other studies have also found ethnic/cultural differences in the use of mental health services (Neighbors et al.
2007). Unwillingness to seek care and/or willingness to provide care in the home that is observed in minority families may extend to the use of acute psychiatric services (Snowden
2007).
Our finding that the enabling factor, homelessness, is associated with high use of mental health services has been noted by others (Arfken et al.
2004; Pasic et al.
2005). In our study, those residing in residential settings and jail were less likely than those living independently to be classified as HU. In contrast, one other study (Pasic et al.
2005) noted that a history of incarceration was related to increased use of mental health services perhaps due the disruption of continuity of care. In regard to those who had some residential services, our results suggest that interventions that include assistance with making and attending appointments and taking medication may lead to decreased use of mental health services. Some studies (Martinez and Burt
2006) have found that permanent supportive housing reduced emergency room use and episodes of inpatient hospitalizations in a group of individuals with comorbid psychiatric and substance use disorders. Gilmer and colleagues (Gilmer et al.
2003) also found significant reductions in the use of hospitalization and other emergency services for adults with serious mental disorders enrolled in a supported housing and assertive community treatment program compared to a matched control group not enrolled in the program. Consistent with the implications of these findings, San Diego County has prioritized supportive housing and developed many new housing resources using funds from the recent enactment of the MHSA.
The association of being enrolled in a medical plan and high utilization of services has been previously reported in the literature (Pasic et al.
2005; Segal et al.
1998). We found that the odds of being a HU was increased by 19% for Medicaid beneficiaries compared to those without Medicaid. Since we determined Medicaid status from the index year, the association between insurance coverage and use of services is most likely due to the fact that individuals with insurance (predominantly Medicaid) were more likely to be hospitalized over the course of the study period. This finding is consistent with a study of enrollment status in a public managed mental health care plan and emergency psychiatric service use that reported that clients with current or previous Medicaid enrollment had more lifetime inpatient hospitalizations than those never enrolled (Wingerson et al.
2001).
As predicted, we found that need was related to mental health service use. Our findings that the likelihood of being classified as a HU increased with higher need for services (i.e., diagnosis of schizophrenia, bipolar disorder, and other psychotic disorder and co-morbid substance use) are consistent with other studies in the literature (Sullivan et al.
1993; Dhossche and Ghani
1998; Hansen and Elliott
1993; Segal et al.
1998; Silva et al.
2009). Some (Pasic et al.
2005) all studies (Arfken et al.
2004) have found a relationship between substance use disorder diagnosis and high utilization of services.
In contrast to many previous studies, we examined acute mental health services beyond just emergency department use, including EPU, PERT, inpatient, and crisis residential services. However, a significant limitation of this study is that we did not differentiate between a HU of services who used multiple acute services in one episode of illness (e.g., presented at EPU, was hospitalized, then discharged to a crisis residential facility) and a person who used three services over more than one episode of illness. The characteristics associated with these patterns of use may differ. Another limitation includes the lack of length of service and cost data, which could yield important information about patterns of service utilization. Furthermore, the secondary use of an administrative database limited the number and types of factors (enabling and need) that we could investigate. In addition, the MIS dataset used in the analyses did not include emergency mental health services provided at private fee for service hospital emergency departments which provide services to Medicaid beneficiaries. Finally, to the extent that the types of acute psychiatric differ from those offered in San Diego County, generalizability may be limited.
Despite these limitations, there were several strengths of our study. We analyzed four consecutive years of data from a large public mental health system which allowed comparison of one-time HUs and multiple-year HUs across time. We also included a greater range of emergency service use across the 4 year study period which allowed inclusion of more individuals in the analysis.
In summary, many of the enabling and need factors found to be associated with the likelihood of being a high use consumer of mental health services (e.g., substance abuse, homelessness, insurance coverage, and minimal outpatient service use) suggest the importance of recognizing the relationship of the public mental health system to other public and private sector service systems. In this regard addressing the needs of HUs of mental health services will likely require the involvement of partnerships across service sectors. Therefore, optimal use of public mental services might be achieved by developing and implementing interventions that also attend to other concerns such as homelessness, insurance coverage, and substance use.
This finding is consistent with one of the major service initiatives instituted through the MHSA—full service partnerships (FSP). The FSP programs are explicitly designed to link persons with mental health concerns to a range of other needed services with the goal of bringing about long-term improvement in mental health status and overall functioning in many facets of life. As the result of the implementation of these programs, we hope to see reductions in the overall numbers of persons characterized as HUs of acute mental health services and the potential for changes in the characteristics associated with HUs.