title: Anxiety and depression, chronic physical conditions, and quality of life in an urban population sample study.
abstract: OBJECTIVE
  No previous studies have empirically demonstrated a multiplicative interactive effect of anxiety disorders and/or depression (ADD) and chronic medical conditions on quality of life (QOL). We hypothesized that QOL impairment was worsened by the presence of ADD and medical co-morbidity, more than when it was with either medical co-morbidity alone or ADD alone.
  
  
  METHODS
  Complete data of 2,801 participants from the National Mental Health Survey of Adults in Singapore were analyzed, using SCAN diagnoses of anxiety disorders and depression, self-reports of chronic medical conditions, and SF-12 measures of QOL (Mental Component Summary, MCS, and Physical Component Summary, PCS).
  
  
  RESULTS
  Persons diagnosed with ADD (compared to those without) had considerably more medical co-morbidities (59 vs. 33%, p < 0.001). In multiple regression analyses, ADD (vs. no ADD) was associated with lower PCS (b = -1.013, p = 0.045) and MCS scores (b = -9.912, p < 0.001), as was number of medical co-morbidities (0, 1-2, 3 +), PCS scores (b = -2.058, p < 0.001) and MCS scores (b = -1.138, p < 0.001). There were significant interactive effects of medical co-morbidities and ADD on PCS (p < 0.001), and MCS (p = 0.086), suggesting that the negative effects of medical conditions on quality of life was aggravated non-additively by the co-morbid presence of ADD, and vice versa.
  
  
  CONCLUSIONS
  The individual effects of medical and psychiatric morbidity on functional status and quality of life were considerably worse when both were present in the same individual. Future studies should examine the impact of identifying and treating anxiety and depressive disorders in patients with medical problems for better outcomes.
authors.affiliation: Department of Psychiatry, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore. leslie.lim.e.c@sgh.com.sg
authors.forename: Leslie
authors.initials: L
authors.lastname: Lim
authors.forename: Ai-Zhen
authors.initials: AZ
authors.lastname: Jin
authors.forename: Tze-Pin
authors.initials: TP
authors.lastname: Ng
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000453:epidemiology*; D002908:Chronic Disease / Q000523:psychology*; D015897:Comorbidity; D003866:Depressive Disorder / Q000453:epidemiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D036301:Qualitative Research; D011788:Quality of Life / Q000523:psychology*; D012044:Regression Analysis; D012846:Singapore / Q000453:epidemiology; D014505:Urban Population; D055815:Young Adult