Introduction

The understanding of eating disorders (EDs) has evolved significantly in the past decade. In conjunction with the clearly defined bulimia nervosa (BN) and anorexia nervosa (AN), the latest revisions, such as the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) [1] released in May 2013 and the 11th revision of the World Health Organization’s International Statistical Classification of Diseases and Related Health Problems (ICD-11) published in 2019 [2], introduce a distinct category known as binge eating disorder (BED). A comparison of the DSM-5 and ICD-11 diagnostic criteria for BED is shown in Table 1. The introduction of the BED diagnosis was prompted by a significant factor: in earlier iterations of diagnostic systems, the classification of Eating Disorder Not Otherwise Specified (EDNOS) occurred most frequently. Consequently, numerous patients exhibit symptoms of an ED but do not meet the criteria for BN or AN [3]. Empirical studies have demonstrated the utility of incorporating BED into the classification of EDs [3]. Despite being recognized relatively recently as a distinct clinical syndrome, BED stands out as the most prevalent ED in the United States, with a lifetime incidence of 2.8%, surpassing the rates of BN (1%) and AN (0.6%) [4]. Moreover, BED potentially has the highest prevalence among EDs globally, boasting a lifetime prevalence of 1.9%, in contrast to the prevalence of 1% for BN [4]. Like in BN and AN, BED occurs more frequently in women than in men, with a lifetime incidence of 3.5% for women compared to 2% for men [5]. Importantly, in both the DSM-5 and ICD-11, the diagnoses of BED and BN are considered mutually exclusive, meaning that during single episodes, only one of the disorders can be assigned; ICD-11 extends this exclusion to AN. Notably, healthcare professionals face significant deficits in knowledge and awareness regarding BED [6]. This lack of awareness, coupled with feelings of shame, constitutes a primary obstacle preventing most affected individuals from receiving the necessary treatment, despite the existence of effective interventions for BED [6].

Table 1 DSM-5 and ICD-11 criteria for binge eating disorder
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BED is a condition characterized by intricate interactions between genetic factors and environmental influences. On the one hand, there are indications pointing to a genetic predisposition [7, 8]. Conversely, the prevalence is significantly influenced by the sociocultural environment and the values practiced within it [9]. For instance, migrants in Australia exhibit a lower incidence of EDs than individuals born in the country [10]. Additionally, specific sociocultural groups, such as Latinos and Blacks, have higher prevalence rates than does the general population [9]. BED may occur not only as a separate phenomenon but also in combination with other mental disorders, adding complexity to the overall burden of the disease. Given the relatively brief history of conceptualizing BED as a distinct disorder, this review aimed to systematize the current knowledge regarding the co-occurrence of BED with other psychiatric disorders. The significance of this article is emphasized by the pivotal role that assessing comorbidities plays in treating BED. Tailored therapies designed to enhance the effectiveness of BED treatment can be developed only by thoroughly considering and addressing comorbidities.

Methods

This review was performed according to the updated version of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA 2020 Statement) [11].

Search strategy and selection process

We identified relevant studies using multiple databases, including MEDLINE, MEDLINE Complete, and Academic Search Ultimate. The search strings used were ‘binge eating disorder’ AND ‘mental health OR mental illness OR mental disorder OR psychiatric illness’.

Due to the inclusion of BED in the DSM-5, our analysis initially centered on studies from 2013 onwards. However, recognizing significant studies incorporating proposed criteria before official inclusion, we extended the scope to 2010. Eventually, ongoing analysis led to further extension to 2023, with the final literature search encompassing studies published between January 1, 2010, and April 30, 2023. The details concerning the selection process are outlined in Fig. 1.

Fig. 1
figure 1

Prisma flow chart

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Inclusion and exclusion criteria

The searching strategy and criteria for inclusion and exclusion were established in accordance with the PICO framework, as recommended by the Cochrane Library for systematic reviews [12]. This framework encompasses the population, intervention, comparator, and outcome of interest (see Table 2). We included articles published in English and within the past 13 years. Articles were excluded if they (1) were not related to BED, (2) did not present empirical data, (3) were not scientifically peer reviewed, (4) were duplicated, (5) did not have full-text available, (6) were not related directly to the subject of the review, or (7) put emphasis on bariatric patients. Out of the 3766 articles found during the initial search, only 63 remained after the application of inclusion/exclusion criteria and were included in the final review.

Table 2 The final inclusion and exclusion criteria using the PICO method
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Results

We analyzed the articles in terms of the co-occurrence of BED with other psychiatric disorders. The selected articles addressed issues related to psychiatric comorbidities, such as other feeding or EDs, mood disorders, anxiety, or fear-related disorders (ADs), disorders specifically associated with stress, impulse control disorders, attention deficit hyperactivity disorder (ADHD), substance use disorders, personality disorders, behavioral disorders, disorders of bodily distress or bodily experience, and schizophrenia. Moreover, associations between BED and suicidal thoughts and behaviors, and sleep disorders were observed.

BED as a main diagnosis

Thirty-two articles describing the comorbidity of BED and other psychiatric disorders involved participants with BED as a main diagnosis [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44] (Table 3).

Table 3 Co-occurrence of BED with other psychiatric disorders
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The most common comorbid psychiatric condition among individuals with BED reported in twenty-nine articles was mood disorders [14,15,16,17,18,19,20,21,22,23,24,25, 27,28,29,30,31,32,33,34,35,36,37,38,39,40,41, 43, 44]. Sixteen articles examined the relationship between BED and anxiety disorders [14, 16, 18, 19, 24, 25, 27, 28, 30,31,32,33,34, 37, 40, 44], and thirteen examined substance use disorders [14,15,16,17, 24, 28, 30, 31, 33, 34, 37, 40, 44]. Twelve articles described the occurrence of symptoms of personality disorders among individuals with BED [13,14,15, 17, 18, 28, 29, 32, 33, 36, 40, 42]. Five articles indicated the relationship between BED and posttraumatic stress disorder, acute stress disorder or/and adjustment disorders [17, 26, 28, 37, 40]; two articles reported the incidence of attention deficit hyperactivity disorder among individuals with BED as well as relationships between BED and schizophrenia [28, 37]. One article highlighted the prevalence of impulse control disorders among BED individuals [30], and another two articles showed the association between BED and behavioral disorders [37, 40]. In addition to the abovementioned psychiatric conditions, two studies assessed sleep disorders among BED individuals [18, 32], and one article assessed suicidality [37]. The data are summarized in Table 3.

Other clinical and community samples with comorbid BED

Thirty-one articles were found in the case of individuals without BED as a main diagnosis [88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118]. Ten studies examined the prevalence and correlates of BED in clinical samples of patients suffering from other psychiatric conditions [88,89,90,91,92,93,94,95,96,97] (Table 4). Six of them included samples of patients with mood disorders [88,89,90,91,92, 97], two studies included patients with OCD [93, 94], and one study assessed BED among patients with heroin use disorder [95]. In summary, the abovementioned studies, which included clinical samples, showed the comorbidity of BED with anxiety disorders, substance use disorders, ADHD, post-traumatic stress disorder (PTSD), behavioral disorders, impulse control disorders, disorders of bodily distress or bodily experience, psychotic disorders, and suicidality.

Table 4 Binge eating in clinical and community samples
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Twelve articles reported data on the prevalence and correlates of BED in population-based samples [98,99,100,101,102,103,104,105,106,107,108,109]. These studies showed the associations of BED with mood disorders, anxiety disorders, substance use disorders, behavioral disorders, PTSD, and ADHD.

Seven articles presented in Table 4 included samples of children and/or adolescents [96, 98, 99, 101, 103, 104, 108] and reported data indicating that among these groups, BED co-occurs with mood disorders, anxiety disorders, ADHD, substance use disorders, behavioral disorders, and suicidality.

Finally, nine articles described the results of studies conducted on community samples [110,111,112,113,114,115,116,117]. Mood disorders, anxiety disorders, behavioral disorders, PTSD, substance use disorders, ADHD, suicidality, psychotic disorders, and sleep problems were found among the correlates of BED in these groups.

Discussion

To the best of our knowledge, this is the first review aimed at consolidating current insights into the comorbidity of BED with other psychiatric disorders. An examination of 63 articles published in the last 13 years revealed associations between BED and various mental disorders, with mood disorders (55 articles), anxiety disorders (36 articles), and substance use disorders (31 articles) emerging as the most prevalent coexisting diagnoses with BED. Other psychiatric conditions that have been found to co-occur with BED include reaction to severe stress and adjustment disorders, impulse control disorder, ADHD, personality disorders, behavioral disorders, disorders of bodily distress, and schizophrenia. Furthermore, this study highlights that BED is associated with suicidality and sleep–wake disorders. Considering the abundance of articles demonstrating elevated co-occurrence rates of mood disorders, anxiety disorders, and substance use disorders among individuals with BED, the findings presented in this manuscript mark a crucial stride toward developing personalized treatment approaches. This objective can be achieved through the implementation of naturalistic study designs that incorporate the treatment of comorbidities, particularly given the evidence indicating that the co-occurrence of mood, anxiety, and/or substance use disorders is associated with a more severe course of BED.

Despite available data pointing to the co-occurrence of BED with psychotic disorders e.g., [28, 39, 91] and impulse control disorders e.g., [30, 93], these connections have received limited attention. A significant avenue for future research lies in exploring the comorbidity of BED with symptoms associated with compulsive sexual behavior disorder, a novel diagnostic entity recently included in the ICD-11 under impulse control disorders. Furthermore, although there is a scarcity of published research on the comorbidity of BED with behavioral disorders and disorders of bodily distress, existing data suggest associations with these psychiatric conditions.

Existing data suggest that BED is linked to an elevated psychiatric and general illness burden. The presence of binge eating behavior may contribute to increased illness complexity, impacting the course of illness and comorbidity, as evidenced in various studies e.g., [92]. Moreover, some studies indicate that individuals with BED are more prone to higher levels of suicidality, as well as substance abuse or dependence [89,90,91, 101].

Regarding treatment efficacy, a study conducted by Robinson and colleagues [36] demonstrated that dialectical behavior therapy (DBT) outperformed active comparison group therapy (ACGT) for individuals with BED who had comorbid avoidant personality disorders or an earlier onset of overweight and dieting (< 15 years old). In a study by Touchette and colleagues [99] involving patients undergoing cognitive behavioral therapy (CBT), it was found that the degree of social embedding and psychopathological comorbidity (both state and trait) served as predictors of treatment outcomes. Higher scores on depressive symptoms, agoraphobia, and extraversion were correlated with less improvement.

Overall, our findings endorse the general assumption of the relationship between BED and general psychopathology. It is crucial for mental health providers to recognize this association to effectively address the diagnostic and therapeutic challenges associated with BED. As conceptualized in our study, impulsive overeating serves as one of the regulatory behaviors aimed at coping with negative emotions e.g., [15, 17, 91]. These traits are commonly associated with mood, anxiety, impulse control, attention deficit and hyperactivity, and personality disorders [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44]. Hence, accurately diagnosing and addressing the underlying psychopathology may also prove beneficial in mitigating this compensatory behavior and alleviating its associated psychological and physical (including metabolic) consequences. A clinical implication from our review is the need to screen for other psychiatric conditions in patients with BED and to identify BED symptoms in those with disorders like personality disorders, ADHD, mood, anxiety, and impulse control disorders. This approach ensures a more accurate diagnosis and more effective treatment plans, improving overall patient outcomes as co-occurring conditions can impact the severity and treatment response of BED.

Limitations

Several limitations of this systematic review warrant brief acknowledgment. Firstly, our literature search was limited to articles published in English, potentially limiting the breadth of available results on the topic. This is particularly noteworthy given that the development of BED appears to be influenced by cultural and socioeconomic factors. Secondly, a significant challenge in comparing selected studies arises from the diverse methodologies employed. While the majority of the relevant studies are cross-sectional, there is a scarcity of data from longitudinal studies or experimental trials, both uncontrolled and randomized controlled. Thirdly, we did not conduct a risk of bias assessment for the included studies. As a result, the potential impact of bias in the included studies on our overall findings should be interpreted with caution. The last limitation of our systematic review is the selection of the temporal scope of the analyzed articles. Due to the inclusion of BED in the DSM-5, initially our analysis focused on studies published from 2013 onwards. However, considering the emergence of significant studies incorporating proposed criteria before BED's official inclusion in the classification, we decided to extend the temporal scope back to 2010. Ultimately, due to ongoing analysis and research efforts, we opted to further extend the temporal scope to 2023.

Conclusions

In conclusion, our systematic review affirms BED as the most prevalent ED, with mood and anxiety disorders being the most common co-occurring conditions. A diagnosis of BED is frequently found in individuals experiencing major depressive disorder, bipolar disorder, or obsessive–compulsive disorder. The heightened presence of symptoms such as depression, anxiety, substance use, and suicide risk underscore the importance of considering these factors in the treatment of individuals diagnosed with BED. Conversely, patients, especially those presenting with mood, anxiety, or substance use disorders, should also be screened for BED. Further research is warranted to elucidate the connections between BED and psychotic disorders, as well as disorders of bodily distress.