Characteristics of subjects with comorbidity of symptoms of generalized anxiety and major depressive disorders and the corresponding threshold and subthreshold conditions in an Arab general population sample

Jude U Ohaeri 1, Abdel W Awadalla

Affiliations

01 March 2012

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doi: 10.12659/msm.882521

Abstract

Background: There is controversy about differential meaningfulness between comorbid generalized anxiety disorder (GAD)/ major depressive disorder (MDD), the corresponding "pure" disorders and subthreshold conditions. We compared subjects who met DSM-IVTR criteria of symptoms and functional impairment for comorbid GAD/MDD, versus those with GAD, MDD, subthreshold conditions, and without significant symptoms. The comparison measures were socio-demographics, clinical severity, and quality of life (QOL).

Material/method: Participants (N=3155: 55.1% female, aged 16-87 yrs) were a general population sample of Kuwaitis who self-completed DSM-IVTR criteria-based questionnaires and the WHOQOL-BREF in 2006/7. We scrutinized the questionnaires and classified them into categories.

Results: Of the 273 GAD and 210 MDD cases, the prevalence of comorbidity among cases with GAD was 30.8%, and 40% among MDD. Of the 398 subthreshold GAD and 194 subthreshold MDD cases, 58 had subthreshold anxiety/depression comorbidity. Comorbid threshold GAD/MDD cases were significantly older, and more likely to be women, divorced and unemployed, compared with GAD and MDD. In all measures, the threshold GAD/MDD comorbidity was the severest condition. There was a monotonic decrease in QOL with increasing anxiety-depression symptoms. For the predictors of subjective QOL, the GAD/MDD comorbidity group differed markedly from the others.

Conclusions: The high prevalence of comorbidity and subthreshold conditions supports the recommendation to assess them routinely, regardless of the primary reason for consultation. Our findings support a dimensional model with comorbid GAD/MDD at the higher end of a continuum, and differing from the "pure" conditions by a later onset and predictors of subjective wellbeing.

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References

  1.  
    1. de Graaf R, Bijl RV, Smit P, et al. Risk factors for 12-month comorbidity of mood, anxiety, and substance use disorders: findings from the Netherlands mental health survey and incidence study. Am J Psychiatry. 2002;159:620–29. - PubMed
  2.  
    1. Das-Munshi J, Goldberg D, Bebbington PE, et al. Public health significance of mixed anxiety and depression: beyond current classification. Br J Psychiatry. 2008;192:171–77. - PubMed
  3.  
    1. Krueger RF, Markon KE. Reinterpreting comorbidity in a model based approach to understanding and classifying psychopathology. Annu Rev Clin Psychol. 2006;2:111–33. - PMC - PubMed
  4.  
    1. Cameron OG. Understanding comorbid depression and anxiety. Psychiatr Times. 2007;24(14)
  5.  
    1. Mofitt TE, Harrington H, Caspi A, et al. Depression and generalized anxiety disorder: cumulative and sequential comorbidity in a birth cohort followed prospectively to age 32 years. Arch Gen Psychiatry. 2007;64:651–60. - PubMed
  6.  
    1. Hirschfield RMA. The comorbidity of major depression and anxiety disorders: recognition and management in primary care. Primary Care Companion J Clin Psychiatry. 2001;3:244–54. - PMC - PubMed
  7.  
    1. Kessler RC, Ormel J, Petukhova M, et al. Development of lifetime comorbidity in the World Health Organization World Mental Health Surveys. Arch Gen Psychiatry. 2011;68:90–100. - PMC - PubMed
  8.  
    1. Kessler RC, Berglund P, Demler O, et al. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the national comorbidity survey replication. Arch Gen Psychiatry. 2005;62:593–602. - PubMed
  9.  
    1. Seedat S, Scott KM, Angermeyer MC, et al. Cross-national associations between gender and mental disorders in the WHO World Mental Health Surveys. Arch Gen Psychiatry. 2009;66:785–95. - PMC - PubMed
  10.  
    1. Scott KM, Von Korff M, Alonso J, et al. Age patterns in the prevalence of DSM-IV depressive/anxiety disorders with and without physical comorbidity. Psychol Med. 2008;38:1659–69. - PMC - PubMed
  11.  
    1. Beekman AT, de Beurs E, van Balkom AJ, et al. Anxiety and depresión in later life: co-occurrence and communality of risk factors. Am J Psychiatry. 2000;157:89–95. - PubMed
  12.  
    1. Judd LL, Akiskal HS, Maser JD, et al. A prospective 12-year study of subsyndromal depressive symptoms in unipolar major depressive disorder. Arch Gen Psychiatry. 1998;55:694–700. - PubMed
  13.  
    1. Sadek N, Bona J. Subsyndromal symptomatic depression: a new concept. Depress Anxiety. 2000;12:30–39. - PubMed
  14.  
    1. Lawrence AE, Brown TA. Differentiating generalized anxiety disorder from anxiety disorder not otherwise specified. J Nerv Ment Dis. 2009;197:879–86. - PubMed
  15.  
    1. Pincus HA, Davis WW, McQueen LE. ‘Subtheshold’ mental disorders. A review and synthesis of studies of minor depresión and ‘other brand names. Br J Psychiatry. 1999;174:288–96. - PubMed
  16.  
    1. O’Neil KA, Podell JL, Benjamin CL, Kendall PC. Comorbid depressive disorders in anxiety-disordered youth: demographic, clinical and family characteristics. Child Psychiatry Human Development. 2010;41:330–41. - PubMed
  17.  
    1. Franco X, Saavedra L, Silverman WK. External validation of comorbid patterns of anxiety disorders in children and adolescents. J Anxiety Disord. 2007;21:717–29. - PMC - PubMed
  18.  
    1. Small DM, Simons AD, Yovanoff P, et al. Silva SG, Lewis CC, Murakami JL, March J: Depressed adolescents and comorbid psychiatric disorders: are there differences in the presentation of depression? J Abnorm Child Psychol. 2008;36:1015–28. - PubMed
  19.  
    1. Masi G, Toni C, Perugi G, et al. Anxiety disorders in children and adolescents with bipolar disorder: a neglected comorbidty. Can J Psychiatry. 2001;46:797–802. - PubMed
  20.  
    1. First MB. DSM-5 proposals for mood disorders: a cost – benefit analysis. Curr Opin Psychiatry. 2011;24:1–9. - PubMed
  21.  
    1. Jacobi F, Wittchen HU, Holting C, et al. Prevalence, co-morbidity and correlates of mental disorders in the general population: results from the German Health Interview and Examination Survey (GHS) Psychol Med. 2004;34:597–611. - PubMed
  22.  
    1. Demyttenaere K, Bruffaerts R, Posada-Villa J, et al. Prevalence, severity, and unmet need for treatment of mental disorders in the World Health Organization World Mental Health Surveys. JAMA. 2004;291:2581–90. - PubMed
  23.  
    1. Karam EG, Mneimmeh ZN, Karam AN, et al. 12-month prevalence and treatment of mental disorders in Lebanon. Lancet. 2006;367(9515):1000–6. - PMC - PubMed
  24.  
    1. Munk-Jorgensen P, Rasmussen I, Allgulander C, et al. Prevalence of generalized anxiety disorder in general practice in Denmark, Finland, Norway and Sweden. Psychiatr Serv. 2006;57:1738–44. - PubMed
  25.  
    1. Wittchen HU, Kessler RC, Beesdo K, et al. Generalized anxiety and depression in primary care: prevalence, recognition and management. J Clin Psychiatry. 2002;63(Suppl 8):24–34. - PubMed
  26.  
    1. Dunlop BW, Davis PG. Combination treatment with benzodiazepines and SSRIs for comorbid anxiety and depression: a review. Primary Care Companion J Clin Psychiatry. 2008;10:222–28. - PMC - PubMed
  27.  
    1. Zimmerman M, Chelminski I. Generalized anxiety disorder in patients with major depression: is DSM-IV’s hierarchy correct? Am J Psychiatry. 2003;160:504–12. - PubMed
  28.  
    1. Broadhead WE, Blazer DG, George LK, Tse CK. Depression, disability days lost from work in a prospective epidemiologic survey. JAMA. 1990;264:2524–28. - PubMed
  29.  
    1. Rai D, Kosidou K, Lundberg M, et al. Psychological distress and risk of long-term disability: population based longitudinal study. J Epidemiol Community Health. 2011 E pub Mar 21. - PubMed
  30.  
    1. Neale MC, Kendler KS. Models of comorbidity for multifactorial disorders. Am J Human Genet. 1995;57:935–53. - PMC - PubMed
  31.  
    1. Means-Christensen AJ, Sherbourne CD, Roy-Byrne PP, et al. In search of mixed anxiety-depressive disorder: a primary care study. Depress Anxiety. 2006;23:183–89. - PubMed
  32.  
    1. Tyrer P. The case for cothymia: mixed anxiety and depression as a single diagnosis. Br J Psychiatry. 2001;179:191–93. - PubMed
  33.  
    1. Tyrer P, Seivewright H, Simmonds S, Johnson T. Prospective studies of cothymia (mixed anxiety-depression): how do they inform clinical practice? Eur Arch Psychiatry Clin Neurosci. 2001;251(Suppl 2):II53–56. - PubMed
  34.  
    1. Ohaeri JU. Treatment of anxiety and depression: a review. International J Ment Health Addict. 2006;4:103–18.
  35.  
    1. Marmorstein NR. Relationship between anxiety and externalizing disorders in youth: the influence of age and gender. J Anxiety Disord. 2007;21:420–32. - PubMed
  36.  
    1. Sunderland M, Mewton L, Slade T, Baillie AJ. Investigating differential symptom profiles in major depressive episode with and without generalized anxiety disorder: true comorbidity or symptom similarity? Psychol Med. 2010;40:1113–23. - PubMed
  37.  
    1. Clark LA, Watson D. Tripartite model of anxiety and depression: psychometric evidence and taxonomic implications. J Abnormal Psychol. 1991;100:316–36. - PubMed
  38.  
    1. Ohaeri JU, Awadalla AW, Gado OM. Relationship between symptoms of generalizad anxiety and major depressive disorders using diagnostic criteria – based instruments. Med Sci Monit. 2011;16(12):PH103–15. - PubMed
  39.  
    1. Al-Turkait FA, Ohaeri JU, El-Abassi AM, Naguy A. Relationship between symptoms of anxiety and depression in a sample of Arab college students using the Hopkins Symptoms Checklist – 25. Psychopathology. 2011;44:230–41. - PubMed
  40.  
    1. Kendler KS, Aggen SH, Knudsen GP, et al. The structure of genetic and environmental risk factors for syndromal and subsyndromal common DSM-IV axis I and all II disorders. Am J Psychiatry. 2011;168(1):29–39. - PMC - PubMed
  41.  
    1. Kendler KS, Gardner CO. Boundaries of major depression: an evaluation of DSM-IV criteria. Am J Psychiatry. 1998;155:172–77. - PubMed
  42.  
    1. Ayuso-Mateos JL, Nuevo R, Verdes E, et al. From depressive symptoms to depressive disorders: the relevance of thresholds. Br J Psychiatry. 2010;196:365–71. - PubMed
  43.  
    1. Angst J, Cui L, Swendsen J, et al. Major depressive disorder with subthreshold bipolarity in the National Comorbidity Survey Replication. Am J Psychiatry. 2010;167:1194–201. - PMC - PubMed
  44.  
    1. Bener A, Ghuloum S, Abou-Saleh MT. Prevalence, symptom patterns and comorbidity of anxiety and depressive disorders in primary care in Qatar. Soc Psychiatry Psychiatr Epidemiol. 2011 Epub Feb 4. - PubMed
  45.  
    1. Sulaiman N, Hamdan A, Tamin H, et al. The prevalence and correlates of depression and anxiety in a sample of diabetic patients in Sharjah, United Arab Emirates. BMC Fam Pract. 2010;11:80. - PMC - PubMed
  46.  
    1. Daradkeh TK, Ghubash R, Abou-Saleh MT. Al Ain community survey of psychiatric morbidity III: the natural history of psychopathology and the utilization rate of psychiatric services. Soc Psychiatry Psychiatr Epidemiol. 2000;35:548–53. - PubMed
  47.  
    1. Lamers F, van Oppen P, Comijs HC, et al. Comorbidity patterns of anxiety and depressive disorders in a large cohort study: the Netherlands Study of Depression and Anxiety (NESDA) J Clin Psychiatry. 2011;72(3):341–48. - PubMed
  48.  
    1. Simms LJ, Gros DF, Watson D, O’Hara MW. Parsing the general and specific components of depression and anxiety with bifactor modeling. Depress Anxiety. 2008;25:E34–E46. - PubMed
  49.  
    1. Al Riyani AA, Al Adawi SH, Al Kharusi HA, et al. Health services utilization by school going Omani adolescents and youths with DSM-IV mental disorders and barriers to service use. Int J Ment Health Syst. 2009;3:22. - PMC - PubMed
  50.  
    1. Wang PS, Aguilar-Gaxiola S, Alonso J, et al. Use of mental health services for anxiety, mood, and substance disorders in 17 countries in the WHO world mental health surveys. Lancet. 2007;370:841–50. - PMC - PubMed
  51.  
    1. Skevington SM, Lofty M, O’Connell KA. The World Health Organization’s WHOQOL-Bref quality of life assessment: psychometric properties and results of the international field trial. A report from the WHOQOL group. Qual Life Res. 2004;13:299–310. - PubMed
  52.  
    1. Spitzer R, Kroenke K, Williams JB. Validation and utility of a self-report version of PRIME-MD. JAMA. 1999;282:1737–44. - PubMed
  53.  
    1. Diez-Quevedo C, Rangil T, Sanchez-Planell L, et al. Validation and utility of the patient health questionnaire in diagnosing mental disorders in 1003 general hospital Spanish inpatients. Psychosom Med. 2001;63:679–86. - PubMed
  54.  
    1. Seitz DP. Screening mnemonic for generalized anxiety disorder. Can Fam Physician. 2005;51:1340–42. - PMC - PubMed
  55.  
    1. Löwe B, Gräfe K, Zipfel S, et al. Diagnosing ICD-10 depressive episodes: superior criterion validity of the Patient Health Questionnaire. Psychother Psychosom. 2004;73:386–90. - PubMed
  56.  
    1. Lubetkin EI, Jia H, Gold MR. Depression, anxiety, and associated health status in low-income Chinese patients. Am J Prev Med. 2003;24:354–60. - PubMed
  57.  
    1. Bech P, Rasmussen NA, Olsen LR, Noerholm V, Abilgaard W. The sensitivity and specificity of the Major Depression Inventory, using the Present State Examination as the index of diagnostic validity. J Affective Disord. 2001;66:159–64. - PubMed
  58.  
    1. Wittchen HU, Boyer P. Screening for anxiety disorders: sensitivity and specificity of the Anxiety Screening Questionnaire (ASQ) Br J Psychiatry. 1998;(Suppl 34):10–17. - PubMed
  59.  
    1. Rief W, Nanke A, Klaiberg A, Braehler E. Base rates for panic and depression according to the Brief Patient Health Questionnaire: a population-based study. J Affect Disord. 2004;82:271–76. - PubMed
  60.  
    1. Martin A, Rief W, Klaiberg A, Braehler E. Validity of the Brief Patient Health Questionnaire Mood Scale (PHQ-9) in the general population. Gen Hosp Psychiatry. 2006;28:71–77. - PubMed
  61.  
    1. Sen S, et al. A prospective cohort study investigating factors associated with depression during internship. Arch Gen Psychiatry. 2010;67(6):557–65. - PMC - PubMed
  62.  
    1. Wittchen HU, Carter RM, Pfister H, et al. Disabilities and quality of life in pure and comorbid generalized anxiety disorder and major depression in a national survey. Int Clin Psychopharmacol. 2000;15:319–28. - PubMed
  63.  
    1. Spitzer RL, Kroenke K, Williams JBW, Lowe B. A brief measure for assessing generalized anxiety disorder: The GAD-7. Arch Internal Med. 2006;166:1092–97. - PubMed
  64.  
    1. Löwe B, Decker O, Müller S, et al. Validation and standardization of the Generalized Anxiety Disorder Screener (GAD-7) in the general population. Med Care. 2008;46:266–74. - PubMed
  65.  
    1. Rodebaugh TL, Holaway RM, Heimberg RG. The factor structure and dimensional scoring of the generalized anxiety disorder questionnaire for DSM-IV. Assessment. 2008;15:343–50. - PubMed
  66.  
    1. Newman MG, Zuelling AR, Kachin KE, et al. Preliminary reliability and validity of the generalized anxiety disorder questionnaire –IV; a revised self-report diagnostic measure of generalized anxiety disorder. Behav Ther. 2002;33:215–33.
  67.  
    1. Ruscio AM, Lane M, Roy-Byrne P, et al. Should excessive worry be required for a diagnosis of generalized anxiety disorder? Results from the US National Comorbidity Survey Replication Psychol Med. 2005;35:1761–72. - PMC - PubMed
  68.  
    1. Eack SM, Greeno CG, Lee BJ. Limitations of the patient health questionnaire in identifying anxiety and depression in community mental health: many cases are undetected. Res Soc Work Pract. 2006;16:625–31. - PMC - PubMed
  69.  
    1. Kessler RC, Brandenburg N, Lane M, et al. Rethinking the duration requirement for generalized anxiety disorder: evidence from the National Comorbidity Survey Replication. Psychol Med. 2005;35:1073–82. - PubMed
  70.  
    1. Ruscio AM, Chiu WT, Roy-Byrne P, et al. Broadening the definition of generalized anxiety disorder: effects on prevalence and associations with other disorders in the National Comorbidity Survey Replication. J Anxiety Disord. 2007;21:662–76. - PMC - PubMed
  71.  
    1. Zinbarg RE, Barlow DH, Liebowitz M, et al. The DSM-IV field trials for mixed anxiety-depression. Am J Psychiatry. 1994;151:1153–62. - PubMed
  72.  
    1. Ohaeri JU, Awadalla AW. The reliability and validity of the short version of the WHO Quality of Life Instrument (WHOQOL-Bref) in an Arab general population sample. Ann Saudi Med. 2009;29:98–104. - PMC - PubMed
  73.  
    1. Ohaeri JU, Awadalla AW, El-Abassi AM, Jacob A. Confirmatory factor analytical study of the WHOQOL-Bref: experience with Sudanese general population and psychiatric samples. BMC Med Res Methodol. 2007;7:37. - PMC - PubMed
  74.  
    1. WHO. WHOQOL User Manual. World Health Organization, Program on Mental Health; Geneva, Switzerland: 1998.
  75.  
    1. Diener E, Suh EM, Lucas RE, Smith HL. Subjective well-being: three decades of progress. Psychol Bull. 1999;125:276–302.
  76.  
    1. Cummins RA. Moving from the quality of life concept to a theory. J Intellect Disabl Res. 2005;49:699–706. - PubMed
  77.  
    1. Katschnig H. How useful is the concept of quality of life in psychiatry? In: Katschnig H, Freeman H, Sartorius N, editors. Quality of life in mental disorders. West Sussex, England: John Wiley & Sons Ltd; 2006. pp. 3–17.
  78.  
    1. Sprangers MA, Sloan JA, Veenhoven R, et al. The establishment of the GENEQOL consortium to investigate the genetic disposition of patient-reported quality of life outcomes. Twins Res Hum Genet. 2009;12:301–11. - PMC - PubMed
  79.  
    1. Sprangers MA, Sloan JA, Barsevick A, et al. Scientific imperatives, clinical implications, and theoretical underpinnings for the investigation of the relationship between genetic variables and patient-reported quality-of-life outcomes. Qual Life Res. 2010;19:1395–403. - PMC - PubMed
  80.  
    1. Barsevick A, Frost M, Zwinderman A, et al. GENEQOL Consortium: I’m so tired: biological and genetic mechanisms of cancer-related fatigue. Qual Life Res. 2010;19:1419–27. - PMC - PubMed
  81.  
    1. Al-Fayez GA, Ohaeri JU. Profile of subjective quality of life and its correlates in a nation-wide sample of high school students in an Arab setting using the WHOQOL-Bref. BMC Psychiatry. 2011;11:71. - PMC - PubMed
  82.  
    1. Marangell LB, Dennehy EB, Miyahara S, et al. The functional impact of subsyndromal depressive symptoms in bipolar disorder: data from STEP-BD. J Affect Disord. 2009;114:58–67. - PMC - PubMed
  83.  
    1. Ohaeri JU, Awadalla AW, Gado OM. Subjective quality of life in a nationwide sample of Kuwaiti subjects using the short version of the WHO Quality of Life Instrument. Soc Psychiatry Psychiatr Epidemiol. 2009;44:693–701. - PubMed
  84.  
    1. van Steen K, Curran D, Kramer J, et al. Multicollinearity in prognostic factor analyses using the EORTC QLQ-C30: identification and impact on model selection. Stats Med. 2002;21:3865–84. - PubMed
  85.  
    1. Varni JW, Burwinkle TM, Seid M, Skarr D. The PedsQLTM 4.0 as a pediatric population health measure: feasibility, reliability and validity. Amb Pediatr. 2003;3:329–41. - PubMed
  86.  
    1. Krueger RF, Markon KE. Understanding psychopathology: melding behavior genetics, personality, and quantitative psychology to develop and empirically based model. Curr Dir Psychol Sci. 2006;15:113–17. - PMC - PubMed
  87.  
    1. Ezpeleta L, Domenech JM, Angold A. A comparison of pure and comorbid CD/ODD and depression. J Child Psychol Psychiatry. 2006;47:704–12. - PubMed
  88.  
    1. Watson D, O’Hara MW, Stuart S. Hierarchical structures of affect and psychopathology and their implications for the classification of emotional disorders. Depress Anxiety. 2008;25:282–88. - PubMed
  89.  
    1. Watson D. Differentiating the mood and anxiety disorders: a quadripartite model. Annu Rev Psychol. 2009;5:221–47. - PubMed
  90.  
    1. Foulds GA, Bedford A. Hierarchy of classes of personal illness. Psychol Med. 1975;5:181–92. - PubMed
  91.  
    1. Lawrence AE, Liverant GI, Rosellini AJ, Brown TA. Generalized anxiety disorder within the course of major depressive disorder: examining the utility of the DSM-IV hierarchy rule. Depress Anxiety. 2009;26:909–16. - PMC - PubMed
  92.  
    1. Aigner M, Forster-Streffleur S, Prause W, et al. What does the WHOQOL-Bref measure? Measurement overlap between quality of life and depressive symptomatology in chronic somatoform disorder. Soc Psychiatry Psychiatr Epidemiol. 2006;41:81–86. - PubMed
  93.  
    1. Saarni SI, Suvisaari J, Sintonen H, et al. Impact of psychiatric disorders on health-related quality of life: general population survey. Br J Psychiatry. 2007;190:326–32. - PubMed
  94.  
    1. Noerholm V, Groenvold M, Watt T, et al. Quality of life in the Danish general population – normative data and validity of WHOQOL-Bref using Rasch and item response theory models. Qual Life Res. 2004;13:531–40. - PubMed
  95.  
    1. Lyness JM, Chapman BP, McGriff J, et al. One-year outcomes of minor and subsyndromal depression in older primary care patients. Int Psychogeratr. 2009;21:60–68. - PMC - PubMed
  96.  
    1. Pigott HE, Leventhal AM, Alter GS, Boren JJ. Efficacy and effectiveness of antidepressants: current status of research. Psychother Psychosom. 2010;79:267–79. - PubMed
  97.  
    1. Tamaniga CA, Davis JM. The neuropharmacology of pstchosis. Schizophr Bull. 2007;33:937–46. - PMC - PubMed

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