Body Dysmorphic Disorder and Major Depressive Episode Have Comorbidity-Independent Associations With Suicidality in an Acute Psychiatric Setting

Internalizing disorders, such as mood and anxiety disorders, are major risk factors for suicidal ideation and behavior (Bentley et al., 2016; Nock et al., 2009, 2010; Sareen et al., 2005). Internalizing disorders frequently co-occur, and it is, therefore, important to determine to what extent individual disorders are uniquely related to suicidality, after adjusting for the effects of co-occurring disorders. Evidence from community samples suggests that mood disorders, trauma-related disorders, obsessive-compulsive disorder (OCD) and to a lesser extent most anxiety disorders, remain independent predictors of suicidal ideation and behaviors even after controlling for the effects of comorbid disorders (Fernández de la Cruz et al., 2017; Nock et al., 2009, 2010; Sareen et al., 2005).

Studies have shown that predictors of suicidality can differ between community and clinical samples (e.g., Brown et al., 2000; Grøholt et al., 2000). However, surprisingly, little is known about the unique relationship between individual diagnoses and suicidality in psychiatric populations. Understanding this relationship is important because in psychiatric settings the risk for suicidality is high and psychiatric diagnoses are often known. Existing evidence from clinical populations suggests that major depressive disorder, bipolar disorder and posttraumatic stress disorder (PTSD) may have unique associations with suicidal ideation and behaviors (Beautrais et al., 1996; Brown et al., 2000; Chioqueta and Stiles, 2003; Marshall et al., 2001; Naragon-Gainey and Watson, 2011). However, the studies to date have been limited by an exclusive focus on a specific disorder (e.g., depressed patients), or by not adequately adjusting for coexisting disorders. In addition, studies on suicidality in internalizing disorders typically do not assess OCD and body dysmorphic disorder (BDD), two severe obsessive-compulsive spectrum disorders (Weingarden et al., 2016) that often co-occur with anxiety and mood disorders (Bjornsson et al., 2010). The absence of BDD from this literature is noteworthy because this disorder is quite prevalent in community, medical and psychiatric settings (Greenberg et al., 2019; Veale et al., 2016), and existing data suggest high rates of suicidality among these patients (Angelakis et al., 2016; Phillips et al., 2005), even when compared to patients with other psychiatric disorders (Phillips and Menard, 2006; Phillips, 2017).

In the current study, we examined whether mood, anxiety, and obsessive-compulsive spectrum disorders (OCD and BDD) were associated with suicidal ideation and behaviors in an acute psychiatric sample. Patients were evaluated during admission to psychiatric treatment in a partial hospital program. Semi-structured interviews were used to assess current psychiatric diagnoses and past-month history of suicidal ideation and suicidal behaviors (i.e., actual, aborted, or interrupted suicide attempts, or preparatory behavior imminently preceding a suicide attempt). We conducted both bivariate (each disorder examined separately) and multivariate (all disorders examined simultaneously) analyses to investigate the associations between the psychiatric disorders and suicidality. Based on prior work in community and clinical samples, we hypothesized that unipolar depression, bipolar depression, PTSD, and BDD would all have unique associations with suicidal ideation and behaviors even after controlling for comorbid disorders in the multivariate analyses.

Table 1 shows the prevalence of psychiatric disorders and suicidality for males and females in the sample. Female patients had higher rates of all the psychiatric disorders assessed, except for bipolar depression, obsessive-compulsive disorder, generalized anxiety disorder and social anxiety disorder. Rates of suicidality did not differ between genders.

The results from the regression analyses are summarized in Table 2. In both bivariate and multivariate analyses, having a diagnosis of BDD significantly increased odds of reporting suicidal ideation and suicidal behaviors. Similarly, MDE was associated with significantly increased odds of reporting suicidal ideation and suicidal behaviors, with little difference between bivariate and multivariate analyses. Table 2 also shows results from analyses where unipolar or bipolar depression were included in the models instead of the global MDE variable. Unipolar depression was associated with increased odds of suicidal ideation but not suicidal behaviors, whereas, bipolar depression was associated with increased odds of suicidal ideation and suicidal behaviors (although only marginally significant in the multivariate analyses). Including these variables in the models instead of MDE did not change the relationship between other disorders (e.g., BDD) and suicidality.

The aim of the study was to examine whether mood, anxiety, and obsessive-compulsive spectrum disorders had unique (comorbidity-independent) associations with suicidality among patients in a partial hospital. The results showed that BDD and mood disorders had significant associations with suicidality, but anxiety disorders, OCD and PTSD were not uniquely related to suicidality in the sample.

Patients with BDD were significantly more likely than other patients to report suicidal behaviors and suicidal ideation. The strength of the relationship between BDD and suicidal behaviors was comparable to the relationship between MDE and suicidal behaviors. The relationship between BDD and suicidality remained virtually unchanged after adjusting for other disorders. These results are consistent with previous studies showing high rates of suicidal thoughts and behavior in patients with BDD (Phillips and Menard, 2006; Phillips, 2017), and extend the literature by showing that BDD in acute psychiatric settings has a unique association with suicidality that is not accounted for by symptoms of other internalizing disorders. Future research is warranted to better understand why BDD patients are vulnerable to suicidality (Witte et al., 2012).

The link between mood disorders and suicidality is well documented, but the strength of the relationship varies substantially depending on the population (e.g., greater in inpatient than outpatient settings; Bostwick and Pankratz, 2000). Here, we found that MDE in a partial hospital setting was associated with increased risk of both suicidal ideation and behaviors, even after controlling for other internalizing disorders. When examining unipolar and bipolar depression separately we found that unipolar depression predicted suicidal ideation, but not suicidal behaviors, and bipolar depression predicted suicidal ideation and marginally predicted suicidal behaviors.

In bivariate analyses, social anxiety disorder was associated with suicidal ideation (but not behavior); however, this association was not significant after adjusting for comorbid disorders. Other disorders assessed – OCD, PTSD and other anxiety disorders – did not have any association with suicidality in the sample. Overall, these findings could suggest that in acute psychiatric populations these diagnoses have limited incremental value in predicting suicidality above and beyond the elevated risk already associated with the population.

However, two caveats should be noted. First, a substantial minority of patients were excluded from the interviews and we do not know if they disproportionally had certain diagnoses. For example, patients with recent severe trauma may have been more likely than other patients to be excluded from the interviews. Second, even though our sample was recruited from a clinically severe population it remains possible that the average symptom severity of specific diagnoses was less than the severity in samples recruited from specific disorder populations (e.g., OCD; Angelakis et al., 2015). Future studies using comprehensive assessment of symptoms and severity is needed to fully understand the relationship between specific psychiatric disorders and suicidality in psychiatric settings.

Studies in general populations have often found that females are more likely than males to contemplate and attempt suicide, while males are more likely than females to die by suicide (Schrijvers et al., 2012). In our sample there were no gender differences in the rates of suicidal ideation or behaviors. This is generally in line with previous studies in clinical samples. For example, Beautrais et al. (1996) reported equal number of male and females in their sample of individuals hospitalized after a serious suicide attempt, and Brown et al. (2000) found no gender difference in the rates of completed suicides among psychiatric outpatients.

The current study had several limitations that need to be considered. First, because of the low base-rates of many of the disorders (e.g., BDD, bipolar depression), the sample size for some analyses was relatively small. Thus, replication in larger samples is warranted. Second, we examined cross-sectional relationships between diagnoses and suicidality. Even though we focused on suicidality in the past month, and it is likely that the psychiatric disorders preceded the suicidality in almost all cases, the temporal relationship between these variables needs to be established in a prospective study. Third, as mentioned above, a minority of patients who admitted to the program did not undergo the structured interviews due to logistic or clinical reasons. It is therefore possible that excluded patients differed from the study sample in important ways. For example, in some cases, patients were excluded because of behavioral problems or acute distress at the day of the interview, and these variables may disproportionally reflect certain diagnoses over others. Fourth, we did not examine symptom severity, functional impairment, or primary diagnoses, which may be important when considering associations between psychiatric disorders and suicidality. Fifth, the sample was relatively homogeneous with respect to ethnicity and race (primarily non-Hispanic and White/Caucasian) and it is not clear how well the findings generalize to other ethnicities, races or socioeconomic classes. Finally, we did not examine several disorders that are known to have strong associations with suicidality, and may have influenced the findings, including personality disorders and psychotic disorders. It is quite possible that other diagnoses not assessed in the study will show unique associations with suicidality in this population.

In conclusion, the findings suggest that MDE and BDD have unique relationships with suicidality in a partial hospital setting that is independent of other internalizing disorders. BDD is a common and often underrecognized disorder (Zimmerman and Mattia, 1998), and clinicians should be aware of elevated risk of suicidality in this population. Further research is needed to better understand the nature of the relationship between BDD and suicidality, and whether the results generalize to other clinical settings.