Prevalence of antidepressant use among older people: Population-based observations

OBJECTIVE: To assess the prevalence of antidepressant use with respect to a ge, gender, and time during a 5-year period from 1993 to 1997. DESIGN: A retrospective, population-based study in which data regarding a c ross-sectional series of annual antidepressant use were obtained from admin istrative claims and census databases for more than 1.4 million alder perso ns during calendar years 1993 through 1997. PARTICIPANTS: All residents of Ontario aged 65 or older. MAIN OUTCOME MEASURES: Changes in the prevalence of antidepressant users as a function of age group, gender, and time. RESULTS: A general, positive, linear trend in the prevalence of antidepress ant users with increasing age group was consistently detected regardless of gender and year assessed (P < .001 for both genders and all years). The ag e-adjusted relative risk of women being dispensed an antidepressant relativ e to men was significantly higher during each year but seemed to decrease s lightly over time: 1.74 (95% CI, 1.72-1.76) in 1993 and 1.65 (95% CI, 1.63- 1.67) in 1997. The multiple linear regression model revealed significant re lationships between the prevalence of antidepressant users and increasing a ge group, female gender, and increasing year of assessment (P < .001 for ea ch variable). The prevalence was observed to range from a low of 5.6% in 65 to 69-year-old men in 1993 to a high of 17.2% among 85 to 89-year-old wome n in 1997. CONCLUSIONS: Our findings reveal that the prevalence of antidepressant user s is dynamic and is significantly and independently associated with age, ge nder, and time of assessment.