title: Use of antidepressants among elderly subjects: trends and contributing factors.
abstract: OBJECTIVE
  The authors assessed changes over time in antidepressant utilization among elderly subjects regarding the prevalence of antidepressant users, shifts in prescription patterns, and related financial implications.
  
  
  METHODS
  The authors conducted a population-based study of more than 1.4 million Ontario residents aged 65 years or older. Cross-sectional data regarding annual antidepressant utilization were obtained from administrative databases for 1993 to 1997. Time series analysis was used to assess trends over time and to make future projections.
  
  
  RESULTS
  The proportion of antidepressant users increased from 9.3% of the elderly population in 1993 to 11.5% in 1997. Prescriptions for selective serotonin reuptake inhibitors (SSRIs) accounted for 9.6% of antidepressant prescriptions dispensed in the first 30 days of 1993 and 45.1% of those dispensed by the last 30 days of 1997 and were projected to increase to approximately 56% by the end of 2000. Prescriptions for tricyclic antidepressants fell from 79.0% in the first 30 days of 1993 to 43.1% by the last 30 days of 1997 and were projected to decline to approximately 28% by the end of 2000. Annual antidepressant costs (in Canadian dollars) increased by 150%, from $10.8 million in 1993 to $27.0 million in 1997. Population shifts and an increase in the prevalence of antidepressant users accounted for at least 20% of this increase, whereas the prescribing transition from tricyclic antidepressants to SSRIs accounted for at least 61% of the increase.
  
  
  CONCLUSIONS
  The introduction of SSRIs has had a substantial financial impact at the drug utilization level. Future research should address the appropriate balancing of the cost of newer agents versus their ostensible advantages.
authors.affiliation: Institute for Clinical Evaluative Sciences, the Center for Addiction and Mental Health, Toronto, Canada. muhammad.mamdani@ices.on.ca
authors.forename: M M
authors.initials: MM
authors.lastname: Mamdani
authors.forename: S V
authors.initials: SV
authors.lastname: Parikh
authors.forename: P C
authors.initials: PC
authors.lastname: Austin
authors.forename: R E
authors.initials: RE
authors.lastname: Upshur
mesh_terms: D000368:Aged; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D000929:Antidepressive Agents, Tricyclic / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000188:drug therapy / Q000453:epidemiology / Q000523:psychology; D016527:Drug Costs / Q000706:statistics & numerical data; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004363:Drug Utilization / Q000639:trends; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D008996:Monoamine Oxidase Inhibitors / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use; D009864:Ontario / Q000453:epidemiology; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use
chemical_list: D000928:Antidepressive Agents; D000929:Antidepressive Agents, Tricyclic; D008996:Monoamine Oxidase Inhibitors; D017367:Selective Serotonin Reuptake Inhibitors