Disability and comorbidity among major depressive disorder and double depression in African–American adults

Abstract

Background

Few studies have examined differences in disability and comorbity among major depressive disorder (MDD), dysthymia, and double depression in African–Americans (AA).

Methods

A secondary analysis was performed on AA in the National Survey of American Life. Interviews occurred 2001–2003. A four stage national area probability sampling was performed. DSM-IV-TR diagnoses were obtained with a modified version of the World Health Organization's expanded version of the Composite International Diagnostic Interview. Disability was measured by interview with the World Health Organization's Disability Assessment Schedule II.

Results

Compared to non-depressed AA, AA endorsing MDD (t=19.0, p=0.0001) and double depression (t=18.7, p=0.0001) reported more global disability; AA endorsing MDD (t=8.5, p=0.0063) reported more disability in the getting around domain; AA endorsing MDD (t=19.1, p=0.0001) and double depression (t=12.1, p=0.0014) reported more disability in the life activities domain. AA who endorsed double depression reported similar disability and comorbidities with AA who endorsed MDD. Few AA endorsed dysthymia.

Limitations

This was a cross-sectional study subject to recall bias. The NSAL did not measure minor depression.

Conclusions

The current study supports the idea of deleting distinct chronic subtypes of depression and consolidating them into a single category termed chronic depression.

Introduction

Depression is the leading cause of disability worldwide and a major contributor to the global burden of disease (World Health Organization (WHO), 2013). Dysthymia is characterized by less severe depressive symptoms than major depressive disorder (MDD) (American Psychiatric Association, 2000). However, recent studies show dysthymia associated with comparable (Subodh et al., 2008) or more disability than MDD (Hellerstein et al., 2010, Rhebergen et al., 2010). Compared to MDD, dysthymia is more likely to have a comorbid anxiety disorder (Rhebergen et al., 2009), which may explain the higher rates of disability associated with dysthymia.

Many individuals with dysthymia develop concurrent MDD, a phenomenon called “double depression” (Keller and Shapiro, 1982). Compared to MDD, double depression is associated with more disability (Hellerstein et al., 2010). Double depression is also associated with more comorbid anxiety (Rhebergen et al., 2012, Sang et al., 2011), panic (Sang et al., 2011) and obsessive–compulsive disorders (Holm-Denoma et al., 2006), and agoraphobias (Sang et al., 2011, Holm-Denoma et al., 2006) which may explain the higher rates of disability in double depression compared to MDD. Double depression and dysthymia have similar disability and comorbidities (Hellerstein et al., 2010, Rhebergen et al., 2009). Few studies have examined differences in disability and comorbity among MDD, dysthymia and double depression and no depression in African–Americans (AA), which is the purpose of this study.