Psychiatric disorder co-morbidity and correlates in an ethnically diverse sample of obese patients with binge eating disorder in primary care settings

Abstract

Objective

To examine DSM-IV lifetime/current psychiatric disorder co-morbidity and correlates in ethnically-diverse obese patients with binge eating disorder (BED) seeking treatment for obesity and binge eating in primary care.

Method

A consecutive series of 142 participants (43% Caucasian, 37% African–American, 13% Hispanic–American, and 7% “other” ethnicity) were evaluated with semi-structured interviews.

Results

67% of BED patients had at least one additional lifetime psychiatric disorder, with mood (49%), anxiety (41%), and substance-use (22%) disorders most common. In terms of current co-morbidity, 37% had at least one other psychiatric disorder, with anxiety (27%) and mood (17%) most common. Few gender differences were observed but psychiatric co-morbidity rates differed across ethnic/racial groups with larger differences for current diagnoses. African–American and Hispanic groups were more than twice as likely as the Caucasian group to have additional current psychiatric disorders, mood disorders, and anxiety disorders. Psychiatric co-morbidity was associated with greater eating-disorder psychopathology and poorer functioning, but not with binge-eating or BMI.

Conclusion

Our study presents new findings suggesting that among obese BED patients in primary care, ethnic/racial minority groups are more likely than Caucasian groups to present with psychiatric co-morbidity. Within BED, psychiatric co-morbidity shows few gender differences but is associated with greater eating-disorder psychopathology and poorer functioning.

Introduction

Binge eating disorder (BED), a research category in the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) [1], is characterized by recurrent binge eating without inappropriate compensatory weight-control behaviors. BED is a prevalent problem strongly associated with obesity and psychosocial impairment [2]. BED has distinctive psychopathology from other disordered eating groups [3], [4] that is significantly elevated relative to obese controls [5], [6]. BED has been added as a formal diagnosis in the current proposal for DSM-5 (www.dsm5.org) as critical reviews have concluded that sufficient evidence exists for BED to warrant its inclusion [7].

The study of diagnostic co-occurrence can contribute to developing models of etiology and has relevance for treatment formulation. Several studies have examined psychiatric co-morbidity in patients with varying definitions of BED using various approaches to recruitment (e.g., community, convenience, treatment-seeking at research clinics), assessment (e.g., self-report and interview methods), and comparison groups. We briefly note here the major findings from selected rigorous studies using diagnostic interviews. In the first controlled study of psychiatric co-morbidity in patients diagnosed with BED, Yanovski and colleagues [8] reported that 43 obese subjects with BED were significantly more likely to have co-occurring DSM-III-R-defined psychiatric disorders than 85 obese subjects without BED (60% versus 34%, respectively). Wilfley and colleagues [9], in a study of 162 patients with BED participating in a clinical trial, found that 77% of the patients met criteria for at least one additional DSM-III-R lifetime psychiatric disorder; mood, substance-use, and anxiety disorders were most common (61%, 33%, and 29%, respectively). Hudson and colleagues [2] reported that 79% of persons with BED met criteria for at least one additional DSM-IV lifetime psychiatric disorder in the National Comorbidity Replication Study; anxiety, mood, and substance use were most common (65%, 46%, and 23%, respectively). Javaras and colleagues [10], in a community-based study, reported elevated rates of most psychiatric disorders in persons with BED relative to those without BED. Grilo and colleagues [11] in a study of 404 consecutive patients with BED assessed at a research clinic reported that 74% met criteria for at least one additional DSM-IV lifetime psychiatric disorder and that 43% had at least one additional current disorder. Lifetime-wise, mood, anxiety, and substance use disorders were most common (54%, 37%, and 25%, respectively) at rates that echo those of the previous reports.

Although research has consistently reported elevated rates of psychiatric co-morbidity in obese BED groups relative to obese groups [10], less is known about the significance of psychiatric co-morbidity within BED (within group correlates). The Wilfley et al [9] DSM-III-R-based study, but not the Grilo et al [11] DSM-IV-based study, found that overall lifetime psychiatric co-morbidity was significantly more likely in men than women, although both studies reported that men were significantly more likely to have lifetime histories of substance use disorders. Grilo et al. [11] and Wilfley et al [9] both found that psychiatric co-morbidity was unrelated to body mass index or to binge-eating frequency; however, Wilfley et al [9] reported no association with eating-disorder psychopathology whereas Grilo et al [11] found significant associations between current psychiatric co-morbidity and higher eating-disorder psychopathology, as did a smaller study by Peterson et al [12] based on self-report measures. Thus, relatively little is known regarding the nature and significance of DSM-IV psychiatric co-morbidity within patient groups with BED. The literature consistently highlights the high rates of co-occurring psychiatric disorders in BED but is mixed regarding the relationship of co-morbid conditions to eating-disorder psychopathology. The mixed findings are perhaps due in part to limited power of some studies and varied recruitment and assessment methods.

The present study examined psychiatric co-morbidity in an ethnically diverse sample of obese patients with BED seeking treatment for obesity and binge eating in primary care, which is important for several reasons. First, the existing clinical literature is based on samples of treatment-seekers from specialist research clinics [9], [11], [12] and those findings may not generalize adequately to other clinical settings due to various “clinic biases” [13], [14], [15]. Second, the existing literature is based on samples comprised predominately of Caucasian participants and findings may not generalize to more diverse groups comprising different ethnic composition [16]. Epidemiological studies have found that African American and Hispanic groups have comparable rates of binge-eating as Caucasians [17], [18] but in sharp contrast to such prevalence data, African–American and Hispanic persons have been vastly under-represented in clinical studies of BED at research clinics [16]. Epidemiological studies have also found that minority groups with binge-eating problems have lower mental health utilization rates than Caucasians and receive most of their health care from generalist or primary care settings rather than from specialist settings [18]. Third, although BED appears to be common in primary care settings and associated with increased medical problems and service utilization [19], research has documented that general healthcare providers are unfamiliar with and often miss problems with BED [20] resulting in little available knowledge about this patient group.