Different characteristics associated with suicide attempts among bipolar I versus bipolar II disorder patients
Introduction
Suicide attempts and death by suicide are common in patients with bipolar disorder (BD) (Schaffer et al., 2015). Individuals with BD nearly always experience both depressive and mood elevation episodes (American Psychiatric Association, 2013). Both persons with BD and unipolar major depressive disorder (MDD) experience depressive episodes (American Psychiatric Association, 2013), which are associated with suicidality (Harris and Barraclough, 1997). However, people with BD have a significantly higher risk of attempting suicide (Chen and Dilsaver, 1996, Gonda et al., 2012), consistent with the pervasiveness of depressive symptoms in BD (Judd and Akiskal, 2003). Lifetime suicide attempt rates in BD vary across reports, from less than 30 percent (Chen and Dilsaver, 1996) to more than 50 percent (Valtonen et al., 2005), possibly related to differences in clinical sample composition. Lifetime history of suicide attempt in BD patients has been consistently associated with several demographic and illness characteristics. These include female gender (Simon et al., 2007, Bellivier et al., 2011), earlier BD onset age (Bellivier et al., 2011), depressive index, current or most recent episodes (Valtonen et al., 2007), comorbid anxiety (Simon et al., 2007), alcohol/substance use (Simon et al., 2007, Bellivier et al., 2011), longer duration of untreated illness (Altamura et al., 2010), cluster B/borderline personality (Sanchez-Gistau et al., 2009) disorders, and having a first-degree relative who died by suicide (Sanchez-Gistau et al., 2009).
Variability in suicide rates in BD could be related to clinical heterogeneity related to varying sample characteristics. These include rates of the main specified BD subtypes (bipolar I disorder, BDI, and bipolar II disorder, BDII) and related clinical characteristics (Dell’Osso et al., 2015). The defining differences between BDI and BDII is that individuals with BDI must have had at least one manic episode, while patients with BDII must have had have at least one hypomanic (but no manic) as well as at least one depressive episode (American Psychiatric Association, 2013). An older belief that BDII merely represented a milder form of illness than BDI, based at least in part, upon the definition of hypomania implying, per se, less severe mood elevation compared to mania, has been increasingly questioned (Judd et al., 2005), with research suggesting that BDII compared to BDI can in multiple ways be more severe, as evidenced by more common associations with multiple unfavorable illness characteristics (Dell’Osso et al., 2015).
Moreover, BDII compared to BDI has been associated with significantly greater risk of prior suicide attempt in a few (Dunner et al., 1976, Rihmer and Pestality, 1999, Serretti et al., 2002, Angst et al., 2005, Baek et al., 2011) but not most (Coryell et al., 1985, Endicott et al., 1985, Coryell et al., 1987, Cassano et al., 1989, Vieta et al., 1997, Dittmann et al., 2002, Dalton et al., 2003, Leverich et al., 2003, Sakamoto and Fukunaga, 2003, Joyce et al., 2004, Moreno and Andrade, 2005, Galfalvy et al., 2006, Pompili et al., 2006, Valtonen et al., 2006, Bader and Dunner, 2007, Tondo et al., 2007, Merikangas et al., 2011) studies. Thus, considered across studies, greater risk of prior suicide attempt has not been consistently associated with either BD subtype (Novick et al., 2010). Hence, studies reported prior suicide attempt rates that were significantly higher in BDII (Dunner et al., 1976, Rihmer and Pestality, 1999, Angst et al., 2005, Baek et al., 2011), significantly higher in BDI (Coryell et al., 1985, Cassano et al., 1989, Tondo et al., 2007), or not significantly different across BD subtypes (Endicott et al., 1985, Coryell et al., 1987, Vieta et al., 1997, Dittmann et al., 2002, Dalton et al., 2003, Leverich et al., 2003, Sakamoto and Fukunaga, 2003, Joyce et al., 2004, Moreno and Andrade, 2005, Galfalvy et al., 2006, Pompili et al., 2006, Valtonen et al., 2006, Bader and Dunner, 2007, Merikangas et al., 2011). We are aware of only very limited research to date regarding how unfavorable clinical characteristics in patients with BDII compared to BDI may contribute to the variable reports of suicide attempt rates by BD subtype (Sublette et al., 2009). Thus, we assessed relationships between BD clinical characteristics and prior suicide attempt rates, stratified by BD subtype.
Section snippets
Method
Participants included adult outpatients with BDI or BDII referred to the Stanford University Bipolar Disorder Clinic by community practitioners (primarily psychiatrists) between 2000 and 2011. At their initial visit, patients were assessed with the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) Affective Disorders Evaluation (Sachs et al., 2002, Sachs et al., 2003, Sachs, 2004), which includes the mood disorders module of the Structured Clinical Interview for the text
Demographics and illness characteristics in bipolar disorder patients (pooled bipolar I disorder and bipolar II disorder)
Table 1 describes demographic and illness characteristics in patients with and without at least 1 prior suicide attempt, stratified by BD subtype and in aggregate.
Clinical and demographic correlates of prior suicide attempt in bipolar disorder patients (pooled bipolar I disorder and bipolar II disorder)
Among the 494 outpatients, individuals with, compared to without at least one prior suicide attempt, were significantly more likely to be female (67.8% versus 54.1%, p < 0.05, Table 1), but did not differ significantly with respect to age, race, or current marital, current employment, or educational status.
Also, considered in
Discussion
In 494 outpatients with BD, different clinical characteristics appeared to increase risks of prior suicide attempts in patients with BDI and BDII. Thus, while the prior suicide attempt rate for all BD patients was second highest among individuals with a lifetime history of eating disorder (47.4%), this appeared to be driven by patients with BDI. In contrast the prior suicide attempt rate for all BD patients was fourth highest among individuals with childhood BD onset (44.3%), and this appeared
Role of funding source
This research was supported by the Pearlstein Family Foundation the Mitchell Foundation, and the Holland Foundation; the funding sources had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.
Disclosure of financial relationships (past 36 months)
Drs. Hooshmand and Wang, as well as Kathryn Goffin and Jessica Holtzman report no financial relationships with commercial interests. Dr. Dell’Osso has received Lecture Honoraria from AstraZeneca and Lundbeck. Dr. Miller has received an honorarium from Pamlab, Inc. Dr. Ketter has received Grant/Research Support from the Agency for Healthcare Research and Quality, AstraZeneca Pharmaceuticals LP, Cephalon Inc., Eli Lilly and Company, National Institute of Mental Health, Pfizer Inc., and Sunovion
Roles of contributors
Kathryn Goffin and Dr. Ketter devised the study.
Drs. Miller, Wang, and Ketter assessed the patients.
Kathryn Goffin assisted with literature review and IRB logistics.
Kathryn Goffin, Jessica Holtzman, and Dr. Hooshmand constructed the electronic database.
Kathryn Goffin, Jessica Holtzman, and Drs. Dell’Osso, Miller, Hooshmand, and Wang performed the data analyses.
Kathryn Goffin wrote the first draft of the manuscript.
All authors revised the draft manuscript.
Acknowledgment
This research was supported by the Pearlstein Family Foundation, the Mitchell Foundation, and the Holland Foundation. These data were presented at the 168th Annual Meeting of the American Psychiatric Association in Toronto, Canada, May 18–22, 2015.
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