Brief report
Prevalence of dysthymic disorder in primary care1

https://doi.org/10.1016/S0165-0327(98)00189-XGet rights and content

Abstract

Background: Dysthymic disorder is characterised as a chronic state of depressed mood which is not otherwise attributable to physical, psychological or social events. While it can occur alone, there is increasing evidence that the majority of individuals who meet criteria for dysthymic disorder also experience more severe episodic mood disorders throughout their lifetime, and there is also an aggregation of mood disorders within their family members. Patients with dysthymic disorder are most often seen in primary care. Some researchers suggest that the majority of these individuals are never diagnosed or are not diagnosed until a more severe episodic mood disorder develops. The objective of this study was to determine the 12-month prevalence of Axis I psychiatric disorders, and in particular dysthymic disorder, in a primary care Health Service Organization in Ontario, Canada. Methods: Eligible and consenting adults registered with a primary care Health Service Organization were screened using the modified form of the University of Michigan Composite International Diagnostic Interview. Results: Of the 6280 eligible subjects, 4327 (69%) consented to screening. Two hundred and twenty-two (5.1%) subjects screened positive for dysthymic disorder. In addition, 90% of those who screened positive for dysthymic disorder also screened positive for other Axis I disorders including major depressive disorder, panic, simple phobia, and generalized anxiety disorder. Conclusions: There is much potential for the primary care physician to play a pivotal role in the recognition and treatment of dysthymic disorder and associated Axis I disorders. A focus on the family as a unit for care may be especially important given the reported aggregation of dysthymic disorder within families.

Introduction

Dysthymic disorder is defined by the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) as a chronically depressed mood for most of the day, for more days than not, for at least 2 years (American Psychiatric Association, 1994). In order to meet DSM-IV criteria, individuals must report at least two of the following symptoms: changes in appetite, sleep disturbance, fatigue, low self-esteem, poor concentration, difficulty making decisions or feelings of hopelessness. Dysthymic disorders are divided by age into early onset (before age 21) and late onset (after age 21) types (American Psychiatric Association, 1994); typically, dysthymic disorder has an insidious onset at an early age with a fluctuating course of symptoms over time (Akiskal, 1983, Akiskal et al., 1995). Dysthymic disorder, also known as dysthymia (Brieger and Marneros, 1997), seems to appear equally in both sexes in children (Garrison et al., 1992); however, in adults it is almost twice as likely to occur in women (Weissman et al., 1988, Kessler et al., 1994). The US National Comorbidity Study reported that the 12-month prevalence of dysthymic disorder in the general population was 2.5% (Kessler et al., 1994), and estimates of lifetime prevalence range from 3.1% (Weissman et al., 1988) to 6.4% (Kessler et al., 1994). It is possible for an individual to have concurrent diagnoses of dysthymic disorder and another mood disorder, in particular major depressive disorder (MDD); this latter condition, known as `double depression' (Keller and Shapiro, 1982), has been the focus of much research.

The etiology of dysthymic disorder is still unknown, although the prevalence of comorbid affective disorders and the results of treatment studies with various antidepressants (Kocsis et al., 1988, Hellerstein et al., 1993, Thase et al., 1996, Lecrubier et al., 1997, Vanelle et al., 1997) suggest that some of the mechanisms of dysthymic disorder and other mood disorders may be shared. Family studies have also shown a strong familial relationship between dysthymic disorder and major depression, with higher rates of mood and personality disorders in first-degree relatives of patients with early onset dysthymic disorder (Klein et al., 1995) as well as in patients with double depression (Donaldson et al., 1997).

Patients with dysthymic disorder are most often seen in primary care. Lifetime prevalence rates from a handful of primary care studies range from 3.7% (Von Korff et al., 1987) to 8.3% (Burnam et al., 1988). There is some evidence to suggest that the majority of these individuals are never diagnosed or are not diagnosed until a more severe episodic mood disorder develops (Keller, 1994). Even when diagnosed, the majority of people with dysthymic disorder are often not treated effectively (Shelton et al., 1997). This is of particular concern as there is considerable data to suggest that chronic subacute depression is a significant risk factor for major depression and should therefore be the focus of efforts both to treat presenting symptoms and to prevent deterioration of mood toward major depression (Judd et al., 1997, Kessler et al., 1997).

The objective of this study was to determine the 12-month prevalence of Axis I psychiatric disorders (DSM-IV), and in particular dysthymic disorder, in a primary care Health Service Organization (HSO) in Ontario, Canada.

Section snippets

Methods

A prospective survey of adults between the ages of 18 and 75 was conducted as the baseline of a multi-arm research study. All individuals registered with a Canadian HSO who were able to provide informed consent were approached. The HSO is a primary health care unit with a roster of 11 000 patients located in Burlington, Ontario. Burlington (population, 137 000) comprises an English-speaking, middle-class, suburban, family community with a small percentage of visible minority groups. This

Results

Of the 6280 individuals who were eligible and were approached to participate in the study, 4327 (69%) agreed to participate (1930 refused and 23 were missed during recruitment). The subjects comprised 1758 males and 2569 females aged 18–75; the mean age of the participants was 46.4 (±15.1) years.

Of the 4327 respondents, 1279 (30%) met criteria for a psychiatric disorder within the past 12 months; 772 screened positive for a single disorder (Table 1), and 507 demonstrated psychiatric comorbidity

Discussion

Consistent with other studies of dysthymic disorder in primary care, the 12-month prevalence of dysthymia was almost twice that of the 12-month prevalence estimate cited for the general population (Kessler et al., 1994). This finding is important as there is increasing evidence that dysthymic disorder may cause significant somatic, social and occupational impairment (Weissman et al., 1988Broadhead et al., 1990Friedman, 1993Howland, 1993Leader and Klein, 1996). Spitzer et al. (1994)have reported

Acknowledgements

We are indebted to Annette Wilkins, Leslie Born and Janice Rogers for their assistance in the preparation of this manuscript, and to Michele Webb, Project Coordinator; to Ellen Jamieson, Data Analyst; to Sherri Colvin, Research Assistant; to the staff at the Caroline Medical Group and the St. Joseph's Hospital Laboratory. Research support: Medical Research Council–Pharmaceutical Manufacturers Association of Canada and Pfizer Canada Inc.

References (33)

  • First, M.B., Spitzer, R.L., Gibbon, M., Williams, J.B.W., 1996. Structured Clinical Interview for DSM-IV, Biometrics...
  • R.A Friedman

    Social impairment in dysthymia

    Psychiatr. Ann.

    (1993)
  • C.Z Garrison et al.

    Major depressive disorder and dysthymia in young adolescents

    Am. J. Epidemiol.

    (1992)
  • H.E Gwirtsman

    Dysthymia and chronic depressive states: diagnostic and pharmaco-therapeutic considerations

    Psychopharmacol. Bull.

    (1994)
  • H.E Gwirtsman et al.

    Standardized assessment of dysthymia: Report of a National Institute of Mental Health Conference

    Psychopharmacol. Bull.

    (1997)
  • D.J Hellerstein et al.

    A randomized double-blind study of fluoxetine versus placebo in the treatment of dysthymia

    Am. J. Psychiatry

    (1993)
  • Cited by (23)

    • Improving work outcomes of dysthymia (persistent depressive disorder) in an employed population

      2015, General Hospital Psychiatry
      Citation Excerpt :

      These are common chronic condition associated with a range of depression symptoms and limitations in social and occupational functioning [1–7]. While its symptoms are less severe than those associated with major depressive disorder (MDD), most individuals (50–75%) with dysthymia also experience recurrent episodes of MDD as well as having functional impairments [2–6,8,9]. The Diagnostic and Statistical Manual of Mental Disorders revisions reflect both the difficulty involved in classifying individuals with chronic depression who do not meet criteria for MDD and establishing a definition that captures the specific burden this condition places on patients.

    View all citing articles on Scopus
    1

    Drs Steiner and Browne are co-principal investigators of this study.

    View full text