Research reportAmerican tertiary clinic-referred bipolar II disorder compared to bipolar I disorder: More severe in multiple ways, but less severe in a few other ways
Introduction
Bipolar disorder (BD) has been conceptualized as a spectrum of related conditions with recurring mood fluctuations (Akiskal and Mallya, 1987, Cassano et al., 1999) and variable prevalence, onset age, course, severity, episode frequency, comorbidity, suicide risk, and treatment response (Ketter, 2010).
Lifetime population prevalence comparison studies between bipolar II disorder (BDII) and bipolar I disorder (BDI) have shown variable results. For example, lifetime prevalence of BDII compared to BDI was slightly higher in the United States National Comorbidity Survey replication (1.1% and 1.0%, respectively) (Merikangas et al., 2007), but marginally lower in a more recent international community survey (0.40% vs. 0.46% respectively) (Merikangas et al., 2011). Nevertheless, some authors contend that BDII may be more common than BDI (Angst, 1998, Parker and Fletcher, 2012).
The older belief that BDII represented a milder form of illness than BDI, which may have been based, at least in part, upon the definition of hypomania implying, per se, less severe mood elevation compared to mania, has been increasingly questioned. Thus, studies have found that BDII compared to BDI can in multiple ways be more severe, as evidenced by more common associations with unfavorable illness characteristics, including more depressive (Endicott et al., 1985, Judd et al., 2003a, Judd et al., 2003b) and overall (Vieta et al., 1997, Goodwin and Jamison, 2007) episodes, more anxiety disorder comorbidity (Rihmer et al., 2001, Henry et al., 2003), more frequent rapid cycling course (Maj et al., 1999, Baldessarini et al., 2000, Kupka et al., 2003), and more family history of mood disorders (Endicott et al., 1985; Benazzi, 2004). Moreover, BDII compared to BDI has been associated with a greater risk of suicide attempt in some (Dunner et al., 1976, Rihmer and Pestality, 1999, Baek et al., 2011) but not all studies (Novick et al., 2010, Valtonen et al., 2005, Merikangas et al., 2011). In contrast, studies have continued to find that BDII compared to BDI in a few ways can be less severe, as evidenced by less common associations with prior psychosis (Vieta et al., 1997) and psychiatric hospitalization (Vieta et al., 1997, Bega et al., 2012).
Other clinical features that have been reported to differ between BDII and BDI patients, but require additional confirmation include: a lower rate of prescription psychotropic ingestion (Coryell et al., 1985, Endicott et al., 1985), and more alcohol abuse in women (Goodwin and Jamison, 2007). Additional parameters that are even less clearly characterized with respect to BDII vs. BDI differences include age at onset, duration of illness, lifetime number of mood elevation episodes, rate of comorbid personality disorders, and recent/current clinical status.
Some studies reported a significantly higher population prevalence of BDII in women (Merikangas et al., 2011) and clinical prevalence of female gender in BDII (Mantere et al., 2004), although most studies did not find any significant gender difference in population prevalence (Diflorio and Jones, 2010). Of note, a higher clinical prevalence of alcohol abuse has been reported in female BDII compared to BDI patients (Goodwin and Jamison, 2007).
Associations with multiple unfavorable illness characteristics, high rates of delayed diagnosis, increased latency to appropriate treatment, and related poor responses can make BDII particularly challenging (Altamura et al., 2010a, Altamura et al., 2010b). Ultimately, such factors may significantly contribute to the very substantial disability and human and economic costs associated with BDII, which are comparable to those reported for BDI and MDD (Benazzi, 2001, Judd et al., 2003b, Joffe et al., 2004, Judd et al., 2005).
In view of the variability in findings, better characterization of differences between BDII and BDI is needed. Specifically, better understanding is needed regarding which patient characteristics contribute importantly to more severe forms of BDII. Such characterization could help inform the treatment of BDII, which is commonly extrapolated from that of BDI and/or MDD, not infrequently yielding suboptimal outcomes. Thus, we assessed clinical prevalence, demographics and illness characteristics in patients with BDII compared to BDI who were referred to an American tertiary BD clinic.
Section snippets
Methods
The current analysis included outpatients with BDII and BDI, referred by community practitioners (primarily psychiatrists) to the Stanford University Bipolar Disorder Clinic between 2000 and 2011. In order for the analysis to reflect phenomenology and treatment as encountered in the community (as opposed to as encountered in a BD research clinic), patients referred from the Stanford University Bipolar Disorder Research Program or previously treated in the Stanford University Bipolar Disorder
Results
Socio-demographic and clinical features for the BDII and BDI subgroups and the entire study sample are reported in Table 1.
Among 503 BD outpatients (mean±SD age 35.6±13.1 years; 58.3% female; with illness duration 17.7±13.1 years; CGI-BP-OS score 3.9±1.5, and taking 2.6±1.7 prescription psychotropics, including benzodiazepines), patients with BDII compared to BDI had statistically similar prevalence (51.7% vs. 48.3%, binomial test, 260 BDII, 243 BDI, df=1, p=0.48) and more severe illness in
Discussion
Results from the present study suggest that in our sample, BDII compared to BDI, had statistically similar prevalence, and was more severe in multiple ways, including more frequently having lifetime anxiety and personality disorder comorbidity, current syndromal/subsyndromal depression, at least 10 prior mood episodes, prior year rapid cycling, childhood onset, a first degree relative with mood disorder, and current antidepressant administration, as well as earlier onset age, longer illness
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.
Acknowledgment
These data were presented at the 166th Annual Meeting of the American Psychiatric Association in San Francisco, California, May 18–22, 2013.
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2019, Psychiatry ResearchCitation Excerpt :The authors added that affective temperaments were associated with specific symptom and psychopathology clusters. More unfavorable illness characteristics (Dell'Osso et al., 2015) including a higher number of episodes (Goodwin and Jamison, 2007), more depressive recurrences (Endicott et al., 1985; Judd et al., 2003a, 2003b), higher rates of anxiety comorbid disorders (Henry et al., 2003; Rihmer et al., 2001), positive history of affective disorders in family (Benazzi, 2004) together with more frequent suicide attempts (Baek et al., 2011; Rihmer and Pestality, 1999) and rapid cycling course (Baldessarini et al., 2000; Kupka et al., 2003) have been described in BD-II when compared to BD-I. In addition, treatment-emergent mania and duration of untreated depression represent a common phenomenon that may allow a more consistent stratification of both the psychopathological and neurobiological BD phenotypes but it is inconsistently reported across primary studies (Fornaro et al., 2018; Ghio et al., 2015).