title: Characteristics of antidepressant medication users in a cohort of mid-age and older Australians.
abstract: OBJECTIVE
  We aimed to investigate antidepressant use, including the class of antidepressant, in mid-age and older Australians according to sociodemographic, lifestyle and physical and mental health-related factors.
  
  
  METHODS
  Baseline questionnaire data on 111,705 concession card holders aged ⩾45 years from the 45 and Up Study-a population-based cohort study from New South Wales, Australia-were linked to administrative pharmaceutical data. Current- and any-antidepressant users were those dispensed medications with Anatomical Therapeutic Chemical classification codes beginning N06A, within ⩽6 months and ⩽19 months before baseline, respectively; non-users had no antidepressants dispensed ⩽19 months before baseline. Multinomial logistic regression was used to calculate adjusted relative risk ratios (aRRRs) for predominantly self-reported factors in relation to antidepressant use.
  
  
  RESULTS
  Some 19% of the study population (15% of males and 23% of females) were dispensed at least one antidepressant during the study period; 40% of participants used selective serotonin reuptake inhibitors (SSRIs) only and 32% used tricyclic antidepressants (TCAs) only. Current antidepressant use was markedly higher in those reporting: severe versus no physical impairment (aRRR 3.86(95%CI 3.67-4.06)); fair/poor versus excellent/very good self-rated health (4.04(3.83-4.25)); high/very high versus low psychological distress (7.22(6.81-7.66)); ever- versus never-diagnosis of depression by a doctor (18.85(17.95-19.79)); low-dose antipsychotic use versus no antipsychotic use (12.26(9.85-15.27)); and dispensing of ⩾10 versus <5 other medications (5.97(5.62-6.34)). Sociodemographic and lifestyle factors were also associated with use, although to a lesser extent. Females, older people, those with lower education and those with poorer health were more likely to be current antidepressant users than non-users and were also more likely to use TCAs-only versus SSRIs-only.
  
  
  CONCLUSIONS
  Use of antidepressants is substantially higher in those with physical ill-health and in those reporting a range of adverse mental health measures. In addition, sociodemographic factors, including sex, age and education were also associated with antidepressant use and the class of antidepressant used.
authors.affiliation: National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia Ellie.Paige@anu.edu.au.
authors.forename: Ellie
authors.initials: E
authors.lastname: Paige
authors.affiliation: National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia.
authors.forename: Rosemary J
authors.initials: RJ
authors.lastname: Korda
authors.affiliation: School of Population Health, The University of Western Australia, Crawley, WA, Australia.
authors.forename: Anna
authors.initials: A
authors.lastname: Kemp
authors.affiliation: Australian Demographic & Social Research Institute, The Australian National University, Canberra, ACT, Australia.
authors.forename: Bryan
authors.initials: B
authors.lastname: Rodgers
authors.affiliation: National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT, Australia The Sax Institute, Sydney, Australia.
authors.forename: Emily
authors.initials: E
authors.lastname: Banks
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000928:Antidepressive Agents / Q000627:therapeutic use*; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001315:Australia; D015331:Cohort Studies; D004363:Drug Utilization / Q000706:statistics & numerical data*; D005260:Female; D006304:Health Status; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D000928:Antidepressive Agents; D014150:Antipsychotic Agents
keywords: Antidepressant medication; cohort studies; population studies