Use of health care services by patients with co-occurring severe mental illness and substance use disorders

Abstract

Background: To better respond to the health care needs of people with co-occurring mental illness and substance use disorders, it is vital to understand their itinerary through the health care system.

Aim: To describe the characteristics of service utilization among patients with co-occurring disorders in a large urban area.

Method: We used a sample (n = 5467) constituted from administrative and clinical databases. Those identified as having substance use disorders and psychoses were followed over 12 months with respect to their utilization of medical services. A descriptive analysis of the data and a two-step cluster analysis were undertaken.

Results: Our analyses revealed a relatively high utilization of emergency services, outpatient clinics, private practices and hospitalization among patients with co-occurring disorders of severe mental illness and substance use. The two-step cluster analysis produced four heterogeneous groups in terms of service utilization.

Conclusions: This study demonstrates the need to develop strategies for organizing health care and services that are adapted to various sites of service utilization and to diverse profiles of patients with co-occurring mental illness and substance use disorders.

Keywords:

• co-morbidity
• co-occurring
• mental health
• substance use disorders
• service utilization

Acknowledgements

Our sincere thanks go to Dr. Lise Lamothe, Dr. Pierre Tousignant, Dr. Michel Perreault, Dr. Céline Mercier and Dr. Richard Cloutier for their feedback, questions and suggestions; and to Yves Roy, Odette Lemoine and Bénoît-Luc St-Pierre for their technical support in extracting and refining the data.

 This project benefited from the technical support of the GRÉAS 1 (Groupe de recherche sur l'équité d'accès et l'organisation des services de santé de 1^re ligne) and financial support from the Canadian Institutes of Health Research within the project number R0013152: Analyse de processus d'intégration des soins et services de 2e et 3e lignes pour les personnes souffrant des troubles concomitants de santé mentale et de toxicomanie [Analysis of processes for the integration of secondary and tertiary-level services for patients with co-occurring mental illness and substance use disorders]. The CIHR also awarded a doctoral fellowship to Marius Kêdoté.

Notes

1. The ICD-9 codes used for drug-induced psychoses are: 292.0, 292.1, 292.2, 292.8, 292.9. Drug-induced psychoses are the only codes that characterize both a mental health disorder and drug use. We are considered these codes as indicators of low-severity co-morbidity when not associated with other mental disorders. Of the 1804 patients with drug-induced psychoses, 854 did not present a diagnosis of any other mental health disorder.

2. The CIM9 codes that refer to severe mental illnesses are: schizophrenic psychoses (2951, 2952, 2953, 2954, 2956, 2957, 2958, 2959); affective psychoses and manic-depressive psychoses (296.0, 296.1, 296.2, 296.4, 296.5, 296.6); personality disorders (301.0, 301.2). The codes used for drug addiction are: alcoholic psychoses (291.0, 291.1, 291.2, 291.3, 291.5, 291.8, 291.9); alcohol dependence syndromes (303.9); drug dependence (304.0, 304.1, 304.3, 304.4, 304.5, 304.6, 304.7, 304.8, 304.9); drug abuse in non-dependent people (305.0, 305.1, 305.2, 305.3, 305.4, 305.5, 305.6, 305.7, 305.8, 305.9; 648.3).

3. Cluster analysis is a method of statistical analysis that enables the classification of individuals into different homogeneous groups according to variables.