A Report on Mental Illnesses in Canada

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APPENDIX A DATA SOURCES

Population Surveys

Over the past two decades, the understanding of the incidence and prevalence of mental disorders has grown with the completion of a number of epidemiological studies in Canada. Using structured interviews based on diagnostic criteria for mental disorders, studies have assessed randomly sampled individuals for current and previous psychiatric symptoms. Researchers have then used the results to estimate the prevalence rates of mental disorders in the general population, and to examine factors that influence the development of mental disorders. Although the data show some variability due to differing assessment tools or methods, the various studies have produced generally similar results. The following summarizes the sources of information cited in this document.

Ontario Health Survey ¹

The Mental Health Supplement of the Ontario Health Survey was a province-wide, cross-sectional epidemiological survey of psychiatric disorders conducted between December 1990 and April 1991 among non-institutionalized Ontarians. The target population consisted of all individuals aged 15 years or older who were residents of private dwellings in Ontario, excluding foreign service personnel, the homeless, people in institutions (e.g., hospitals and correctional facilities), First Nations people living on reserves, and residents of extremely remote areas. A revised version of the Composite International Diagnostic Interview (UM-CIDI) was used to measure psychiatric disorder, providing prevalence data on 14 DSM-III-R disorders. This instrument was also used to collect data in the National Comorbidity Survey in the United States. The Mental Health Supplement of the Ontario Health Survey provides data on 8116 respondents 15 to 64 years of age.

Edmonton Survey of Psychiatric Disorders ^2,3

The Edmonton Survey of Psychiatric Disorders was conducted as a community-based survey in Edmonton, Alberta, between January 1983 and May 1986. Subjects were selected by means of a 2-stage sampling design: in the first stage, households were systematically sampled from a list of residential addresses; and in the second stage, one member from each household was selected using a respondent selection grid to ensure that the age and sex composition of the sample was representative of the participating households. Individuals 18 years of age and older were interviewed using Version III of the Diagnostic Interview Schedule (DIS), with a sample size of 3,258 non-institutionalized individuals.

National Population Health Survey (NPHS)

Statistics Canada conducts the National Population Health Survey (NPHS), a cross-sectional and longitudinal household-based survey, every 2 years. Designed to collect information about the health status of Canadians, the NPHS expands our knowledge of the determinants of health, including health behaviour, use of health services and socio-demographic information. The target population consists of household residents aged 15 years or older in all provinces, except for people living on Native reserves, on Canadian Forces bases, or in some remote areas. The survey has specific components for individuals living in institutions (long-term residents of hospitals and residential care facilities) and in the territories. The NPHS surveyed approximately 20,725 individuals in the first wave in 1994/1995, and 67,133 individuals in 1996/1997 (with longitudinal data on 12,628 individuals).

Hospitalization Data

The Canadian Institute for Health Information (CIHI) maintains the Hospital Morbidity Database (HMDB), which covers hospital separations in Canada. (A hospital separation is defined as the discharge or death of an inpatient and is based on counts of events, not patients. For example, a patient admitted and discharged three times during the reporting year would be counted as three separations. Excluded from the calculations are patients who were admitted to hospital in the previous or current year and were not discharged or died.) A record is completed by the hospital for each individual. In addition to demographic and administrative information, the database contains up to 16 diagnostic codes and some procedures codes.

The HMDB contains separation records from general and allied special hospitals, including acute care, convalescence, and chronic care facilities (except in Ontario). The tables presented exclude newborns, out of province admissions and a small number of records flagged as having serious errors. Records are not available for the Ontario Chronic Care Patient System which accounted for about 1% of admissions in fiscal 1996/97.

Mortality Database - Statistics Canada

Provincial and territorial offices of vital statistics submit information annually on all deaths from all provincial and territorial vital statistics registries in Canada. The personal information portion of the death registration form is completed by an informant, usually a relative of the deceased. The portion of the form comprising the medical certificate of death is completed by the medical practitioner last in attendance, or by a coroner if an inquest or enquiry was held. The database includes demographic information and the underlying cause of death as defined by the physician.

Epidemiological Terms

Age-standardized rate

An adjusted rate that represents what the crude rate would have been in the study population (such as a province or a census division) if that population had the same age distribution as the standard population, which in this report is the 1991 Canadian population. However, because standardization produces a summary measure, it may obscure important differences in the agespecific patterns. Also, standardized rates can be compared with each other only when the same standard population has been used to obtain the rate.

ICD Codes used in analysis

Anxiety: 300.0, 300.2, 300.3, 309.8
Bipolar/emotional disorders: 296.0, 296.4, 296.5, 296.6, 296.7
Depression: 296.2, 296.3, 300.4, 311
Eating disorders: 307.1, 307.5
Personality disorders: 301
Schizophrenia: 295
Suicide: E950 - E959

Incidence rate

The number of new cases per the population at risk of the disease during a specific period.

Prevalence rate

The number of individuals in the population with the disease at a specific point in time, or during a specific period of time.

References

1. Offord DR, Boyle MH, Campbell D, Goering P, Lin E, Wong M et al. One-year prevalence of psychiatric disorder in Ontarians 15 to 64 years of age. Can J Psychiatry 1966;41:559-563.
2. Orn H, Newman SC, Bland RC. Design and field methods of the Edmonton Survey of Psychiatric Disorders. Acta Psychiatr Scand 1988;77(Suppl 338):17-23.
3. Bland RC, Orn H, Newman SC. Lifetime prevalence of psychiatric disorders in Edmonton. Acta Psychiatr Scand Suppl 1988;38:24-32.

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