Psychiatric epidemiology of the elderly population in Chile.

OBJECTIVES

Little attention has been given to the prevalence rate of mental illness among elderly adults in Latin America. The prevalence rates for psychiatric disorders in Chile among those 65 and older compared with younger individuals, and the prevalence rate of psychiatric disorders among those age 75 and older are presented.

DESIGN

A stratified random sample of 2,659 individuals.

SETTING

Four provinces representative of the Chile's population were surveyed.

PARTICIPANTS

Adults age 15 and older were interviewed; however, the analysis is limited to those over age 20.

MEASUREMENTS: The Composite International Diagnostic Interview was administered to obtain Diagnostic and Statistical Manual of Mental Disorders, Third Edition-R diagnoses. Lifetime and 12-month prevalence rates were estimated.

RESULTS

Of the 2,659 interviewed 352 were over age 64. Overall, elderly adults had lower prevalence rates of lifetime disorders than the younger population, 20% in comparison with 34%. Dysthymia, agoraphobia, simple phobia, and alcohol dependence disorders were noted to be less common among elderly subjects. Those over the age of 64 in comparison with those over the age of 74 had higher prevalence rates of disorders. A sizable proportion of the disorders among older adults began after the age of 59. One third of elderly respondents with major depression had a late onset disorder. Service utilization was similar between elderly individuals and younger respondents, except for use of specialized psychiatric services, which was lower among elderly adults.

CONCLUSIONS

Both lifetime and 1-year prevalence of mental disorders were less common in older than in younger persons; however, among elderly adults late onset disorders were not uncommon. Additional studies of the prevalence rates of disorders among older individuals in Latin America are needed for public health planning.