Journal of Affective Disorders 104 (2007) 53–60www.elsevier.com/locate/jad

Research report

Psychosocial impairment associated with bipolar II disorder

Camilo J. Ruggero⁎, Iwona Chelminski, Diane Young, Mark Zimmerman

Department of Psychiatry and Human Behavior, Brown Medical School, Rhode Island Hospital, Providence, RI, United States

Received 18 December 2006; received in revised form 31 January 2007; accepted 31 January 2007Available online 6 March 2007

Abstract

Background: Significant research has looked at the psychosocial impairment associated with bipolar I disorder and majordepressive disorder. Far less is known about the impact of bipolar II disorder. The present study assessed the social and workimpairment associated with bipolar II disorder and whether these are more or less severe than those associated with bipolar Idisorder or major depressive disorder.Methods: Psychiatric outpatients with bipolar II disorder (n=89), bipolar I disorder (n=45) and major depressive disorder(n=1251) were assessed cross-sectionally by highly trained raters using semi-structured interviews. Participants were in a majordepressive episode. Groups were compared on a series of indicators of psychosocial functioning.Results: Bipolar I and II disorder were associated with greater absenteeism from work due to psychopathology compared to majordepressive disorder. The bipolar disorders also had higher rates of hospitalization and suicide attempts. Bipolar II disorder hadfewer hospitalization than bipolar I disorder which may have led to slightly less severe work impairment. Both conditions hadsimilar rates of serious suicide attempts.Limitations: The study was cross-sectional and retrospective. Furthermore, the sample consisted of outpatients seeking treatment,limiting generalizability to other settings.Conclusion: Bipolar II disorder is associated with serious work impairment and a high number of serious suicide attempts. Thelevel of impairment is more similar than it is different from that associated with bipolar I disorder. Clinicians would be mistaken topresume that the “softer” bipolar spectrum, specifically bipolar II disorder, is less impairing than bipolar I disorder.© 2007 Elsevier B.V. All rights reserved.

Keywords: Bipolar II disorder; Psychosocial functioning; Bipolar disorder; Depression; Impairment

1. Introduction

The World Health Organization (WHO) has consis-tently ranked bipolar disorder as one of the top tenleading causes of disability world-wide among adults(Ayuso-Mateos, 2006; Murray and Lopez, 1996). Fewstudies, however, have considered the psychosocial

⁎ Corresponding author. Bayside Medical Center, 235 Plain Street,Suite 501, Providence, RI 02905, United States.

E-mail address: Camilo_Ruggero@brown.edu (C.J. Ruggero).

0165-0327/$ - see front matter © 2007 Elsevier B.V. All rights reserved.doi:10.1016/j.jad.2007.01.035

consequences associated with bipolar II disorder orwhether these are more or less severe than those seen inbipolar I disorder. Almost all work reporting the impactof “bipolar disorder” is based on participants withbipolar I disorder, or might incorporate a small group ofpeople with bipolar II disorder without explicitlycomparing the two groups (e.g., Kessler et al., 2006;Altshuler et al., 2006). These studies note the seriouspsychosocial consequences of bipolar I disorder,including impairment in nearly all areas of psychosocialfunctioning as well as increased risk of death from

54 C.J. Ruggero et al. / Journal of Affective Disorders 104 (2007) 53–60

suicide (see Simon, 2003; Kleinman et al., 2003, forreviews).

Unfortunately, with just a few exceptions, the lite-rature does not address the question of whether thebroader spectrum, specifically bipolar II disorder, is alsoassociated with serious impairment. A priori, cliniciansmight assume more serious impairment with bipolar Idisorder. As originally conceptualized (Dunner et al.,1975) and codified in the Diagnostic and StatisticalManual of Mental Disorder, fourth edition, text revision(DSM-IV-TR; American Psychiatric Association, 2000),the primary distinction between the two disorders isbased not on the duration of manic symptoms but rathertheir severity: manic episodes in bipolar I disorder aresevere enough to cause major disruptions in a person'slife, such as hospitalization, whereas hypomanicepisodes do not. While true, the bipolar II diagnosisrequires episodes of depression, which carry their ownsocial and economic burden (Wells et al., 1989). Indeed,some studies have found that, at least among peoplewith bipolar I disorder, past number of depressiveepisodes more strongly predicted functioning thanmania (MacQueen et al., 2000). As a result, it remainsunclear whether one disorder is associated with worsepsychosocial functioning than the other.

In recent years, there has been increasing interest inthe “soft” bipolar spectrum. This is no doubt related inpart to research (e.g., Akiskal et al., 2000) suggestingthat these disorders are under-recognized. Traditionalestimates indicate lifetime prevalence rates of bipolar IIdisorder of about 1–2%, but others (e.g., Angst, 1998)have argued that prevalence rates are closer to 5.5%.Including disorders that do not currently meet DSM-IVcriteria for bipolar I or II disorder (e.g., “briefhypomania”) raises this estimate up to 20% (Angst,1998).

Regardless of the prevalence, there is a need toclarify the impact of bipolar II disorder on functioning.The handful of studies that have considered the impactof bipolar II disorder offer mixed results. The NationalInstitute of Mental Health Collaborative DepressionStudy (CDS; Judd et al., 2003, 2005), perhaps the mostrigorous of these studies, prospectively assessed func-tioning in a group of participants with bipolar I and IIdisorder. They found that depressive symptoms weremore disabling than hypomanic ones; surprisingly, theyalso found depressive symptoms to be as disabling if notmore disabling than manic symptoms. Consequently,after controlling for difference in depression severity, theyfound no overall difference in psychosocial disabilitybetween bipolar I and II disorder. To the extent thatdepression is more chronic in bipolar II disorder (Judd

et al., 2003), psychosocial impairment may be worse inbipolar II disorder, not bipolar I disorder.

Other studies offer inconsistent results about theimpact of bipolar II disorder and whether impairment ismore or less severe than in bipolar I disorder. In a smallsample, Robb and colleagues (1997; also see Cookeet al., 1996) found greater self-reported intrusivenessfrom their disorder in bipolar II disorder compared tobipolar I disorder, although these differences may havebeen due entirely to greater current levels of depressionin the bipolar II group. Judd and Akiskal (2003) foundsimilar rates of social disruption among varioussubtypes of bipolar disorder in a reanalysis of datafrom the Epidemiological Catchment Area study,although there was a trend for increased risk of suicidalbehavior in the bipolar II group. Hajek and colleagues(2005) found no difference between bipolar I and IIdisorder on a global measure of functioning. In contrastto these studies, Suppes et al. (2001) found that a groupof outpatients with bipolar I disorder had an earlier ageof onset, more hospitalizations, and lower incomecompared to a group with bipolar II or bipolar NOSdisorder, despite that the bipolar II group had signifi-cantly more past episodes of depression.

In sum, considerable work has documented thepsychosocial impact of bipolar I disorder, but far lessresearch has looked at the consequences associated withbipolar II disorder. The research that does exist isinconclusive about whether bipolar II disorder is moreor less impairing than other affective disorders, althoughfindings from more rigorous studies suggest thatdepressive symptoms, not manic ones, exert a greaterimpact on a person's psychosocial functioning.

The present work from the Rhode Island Methods toImprove Diagnostic Assessment and Services (MIDAS)project sought to clarify the psychosocial consequencesassociated with bipolar II disorder and test whether theseare more or less severe than those observed in bipolar I ormajor depressive disorder. A group of participants withbipolar II disorder, bipolar I disorder andmajor depressivedisorder (MDD) were compared on a series of indicatorsof functioning, including work functioning (i.e., absen-teeism), social functioning, divorce rates, global assess-ment of functioning, and suicide risk. Participants in allthree groups were in a current depressive episode. Unlikeprevious work, the present study was careful to determinethe need to control for differences in baseline character-istics (e.g., depression severity, demographics) that mightproduce differences in functioning between groups.Given trends from previous studies (Judd et al., 2005),we tentatively hypothesized that the bipolar II groupwould have worse functioning across measures but that

Table 1Demographic and clinical variables by group (N=1385)

Variable Bipolar I disorder(BPI), n=45

Bipolar II disorder(BPII), n=89

Major depressive disorder(MDD), n=1251

F or χ2 p Significant posthocdifferences

GenderMale 33% 39% 34%Female 67% 61% 66% 1.23 .54 na

Marital statusMarried 44% 37% 49%Divorced/separated 18% 29% 22%Never married 38% 34% 29% 6.87 .14 na

Race/ethnicityCaucasian 89% 95% 85%Hispanic 2% 0% 5%African American 4% 0% 4%Other 4% 5% 6% 9.62 .14 na

EducationLess than HS 11% 8% 11%HS or some college 53% 57% 55%College or beyond 36% 35% 34% .83 .93 na

Age 34.78 (10.49) 35.90 (11.08) 38.82 (12.32) 4.57⁎ .01 BPI, BPIIbMDDCGI-S 2.93 (.99) 2.83 (.94) 2.88 (.87) .23 .80 naLength of current depressive

episode (weeks) a75.84 (97.20) 79.56 (95.62) 95.70 (101.03) 1.81 .17 na

Age of illness onset 16.80 (10.36) 16.43 (8.89) 26.14 (13.82) 30.74⁎⁎ b .001 BPI, BPIIbMDD# of depressive episodes a 10.36 (8.43) 9.57 (8.12) 3.43 (4.68) 94.85⁎⁎ b .001 BPI, BPIINMDD# of previous depressive

episodes0 11% 15% 46% 89.68⁎⁎ b .001 BPI, BPII≠MDD1 to 2 27% 25% 30%3 or more 62% 60% 24%

% ever hospitalized 71% 40% 26% 49.65⁎⁎ b .001 BPINBPIINMDD# of hospitalizations 2.18 (2.00) 1.01 (1.66) .48 (1.03) 57.41⁎⁎ b .001 BPINBPIINMDD

Note. Values for continuous variables represent means (with standard deviations).⁎pb .05.⁎⁎pb .01.a Maximum duration recorded was 260 weeks; maximum depressive episodes recorded was 20.

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this difference would be accounted for by differences incurrent or past symptoms of depression.

2. Methods

2.1. Subjects

Participants for this study were 1385 psychiatricpatients who had sought treatment in the outpatientpractice of Rhode Island Hospital's Department ofPsychiatry in Providence, Rhode Island. One group ofparticipants (n=89) was diagnosed with bipolar IIdisorder. Another group (n=45) had a diagnosis ofbipolar I disorder and a third group (n=1251) had adiagnosis of a major depressive disorder. All participantswere seeking treatment during a major depressiveepisode. No participant was in a manic or hypomanicepisode. Table 1 reports the sample's demographic andclinical characteristics.

All participants had enrolled in the MIDAS project;this unique study integrates assessment methods typicalof researchers into a routine clinical practice (Zimmer-man, 2003). The practice predominantly serves indivi-duals with medical insurance on a fee-for-service basis,and is distinct from the hospital's outpatient residencytraining clinic that mostly serves lower income,uninsured patients. The primary referral source isprimary care physicians and psychotherapists.

Patients who enter this practice and who consent toparticipate in research are administered a battery ofinterview assessments (see Measures section). TheRhode Island Hospital's institutional review committeeapproved the research protocol, and all patientsprovided written informed consent.

2.1.1. Diagnostic rater training and reliabilityAll measures, including those establishing diagnosis,

were administered by highly trained raters who were

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monitored throughout the project to minimize rater drift.Raters are Ph.D.-level psychologists and researchassistants with college degrees in the biological orsocial sciences. Research assistants received 3 to4 months of training during which they observed atleast 20 interviews and were observed and supervised intheir administration of 20 more evaluations. Psycholo-gists only observed 5 interviews; however, they wereobserved and supervised in their administration of 15 to20 interviews. At the end of training, raters wererequired to demonstrate exact or near exact agreementwith a senior diagnostician on five consecutive evalua-tions. Throughout the project, ongoing supervision iscarried out through weekly case conferences involvingall raters. Furthermore, the director of the MIDASproject (MZ) reviews every interview on an item-by-item basis and individually discusses each interviewwith raters. Joint-interview diagnostic reliability forSCID diagnoses was assessed in a subset of patients(n=48) in the MIDAS project. Reliability estimates(kappa) for major depressive disorder and bipolardisorders were .91 and .85, respectively.

2.2. Measures

2.2.1. Clinical measuresTo assess for DSM-IV Axis I disorders, all partici-

pants were administered the Structured Clinical Inter-view for DSM-IV (SCID; First et al., 1995). The SCIDwas modified so that ratings for the Schedule ofAffective Disorder (SADS; Endicott and Spitzer,1978) were also gathered. Current depressive illnessseverity was measured using the Clinical GlobalImpression — Severity scale (CGI-S; Guy, 1976).

2.2.2. Outcome measuresThe Global Assessment of Functioning scale (derived

from the Global Assessment Scale; Endicott et al., 1976)is an interviewer-rated globalmeasure of overall symptomseverity and functioning. Scores range from 0 to 100 withlower scores indicating poorer functioning. As part of theclinical interview, information was also gathered on thenumber of serious and non-serious suicide attempts, usingSADS criteria and anchors. Serious suicide attempts wereany in which there was an actual medical threat (e.g.,. cutthroat, briefly unconscious) to the person's life or therewas serious intent to kill him or herself. These attemptswere distinguished from non-serious attempts, in whichtherewas onlymildmedical threat (e.g., 10 aspirins) or theperson's intention contained some ambivalence.

Raters also gathered information regarding partici-pants social and work functioning history over the last

five years. Ratings for social functioning were fromSADS items, with ratings ranging from “superior socialfunctioning” to “grossly inadequate functioning.” Eachrating was accompanied by anchors to guide the rater'schoice. Moreover, raters used multiple queries to assesslevel of social functioning in the past 5 years. Queriesincluded questions about the number of confidants aswell as the frequency with which participants had socialcontact. Work functioning was assessed by determiningthe number of days in the last 5 years for which thepatient had been unable to work due to their psychiatricillness. People not expected to work were considered tohave not lost any days of work due to their illness. Theratings also did not include days out of work due to otherreasons (e.g., medical illness).

2.3. Statistical analyses

For all analyses, a family wise error rate of .05 wasset. Bonferroni adjustments to this level were made ifmultiple tests were carried out. Prior to conductingprimary analyses, preliminary data screening steps weretaken. Great care was made to avoid missing data duringthe study, such that almost no missing data (i.e. less than1%) existed on primary, interviewer gathered outcomedata or on predictors; as such, standard deletion methodswere deemed appropriate (Allison, 2002). Analyseswere then performed to detect outliers (e.g., inspectionof cases with large standardized scores) and testassumptions (e.g., normality, homogeneity of var-iances). Several outliers were detected. However, allremained in acceptable ranges and were not removed.All variables except for hospitalizations had acceptableskew and kurtosis. Furthermore, the work functioningvariables violated the homogeneity of variances as-sumption. These two variables were logarithmicallytransformed. After transformation, they had acceptableskew and kurtosis and did not violate assumptions.

Following preliminary data screening, the need tocontrol for confounds in the primary analyses was nextconsidered. A confound was regarded as any baselinevariable (e.g., age) that was significantly different in thethree groups and was associated with outcomes; if onlythe former was true, the variable represents a covariaterather than a true confound and was not necessarilycontrolled for.

Primary analyses were next carried out. These fo-cused on group differences in psychosocial functioningoutcomes. A one-way ANOVA was performed on eachoutcome (i.e., GAF, work functioning, social function-ing, divorces, suicide attempts, and current self-reportedfunctioning and quality of life) with group (i.e., bipolar

Table 2Primary outcomes by group (N=1385)

Variable Bipolar I disorder(BPI), n=45

Bipolar II disorder(BPII), n=89

Major depressive disorder(MDD), n=1251

F or χ2 p Significant post hocdifferences

GAF 48.16 (8.85) 48.61 (8.79) 50.86 (8.85) 4.51⁎ .01 BPI, BPIIbMDDa

SADS work functioningrating

4.44 (2.71) 3.19 (2.44) 2.34 (1.88) 31.96⁎⁎ b .001 BPINBPIINMDDb

Absenteeism due topsychopathologyLess than 1 year 42% 67% 84% 60.04⁎⁎ b .001 BPINBPIINMDDb

More than 1 year 58% 33% 16%SADS social functioning

rating3.38 (1.37) 3.18 (1.19) 3.19 (1.24) .52 .59 na

Social functioningGood to superior 62% 62% 66% 5.56 .23 naFair 16% 27% 21%Poor to gross 22% 11% 13%

# of divorces .49 (.84) .37 (.57) .37 (.63) .78 .46 na% ever having been divorced 33% 33% 30% .38 .83 na# of serious suicide attempts .91 (2.09) .63 (1.48) .25 (1.03) 11.98⁎⁎ b .001 BPI, BPIINMDDa

% ever having made a serioussuicide attempt

33% 27% 13% 25.18⁎⁎ b .001 BPI, BPIINMDDa

Note. Means and significance test are based on raw, untransformed scores. They are not adjusted for group differences in confounds.⁎pb .05, ⁎⁎pb .01.a After adjusting for confounds, groups no longer differed.b After adjusting for confounds, the bipolar I and MDD groups differed, but the bipolar II group did not differ from either of these.

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I, bipolar II, and MDD) as the independent variable.When it was necessary to control for confounds, anANCOVA was used instead as long as assumptionsregarding the covariate were not violated (e.g., homo-geneity of regression coefficients). Significant omnibustests were followed by post hoc tests.

3. Results

Groups did not differ in the severity of currentdepressive episodes (i.e., CGI-S; see Table 1). There-fore, this variable was not controlled for in subsequentanalyses. Several baseline variables, however, wereidentified as potential confounds, in that they differedbetween groups (Table 1). These included age, age ofillness onset, past number of depressive episodes andhospitalizations. Only the last three were significantafter adjusting the familywise error rate for multipletests.

The bipolar I and II groups had younger ages of onsetand significantly more past episodes of depression thattheMDDgroup. In both cases, however, the bipolar I andII groups did not differ from each other. There was,however, a significant difference among all three groupswith respect to the number of times they had beenhospitalized. The bipolar I group had significantly morehospitalizations than the bipolar II group. In turn, thelatter group had significantly more hospitalizations

than the MDD group. Exploratory analyses consideredwhether differences in hospitalization were due to moredepressive episodes or to differences in age of onset:after controlling for both variables, there continued to besignificant group differences, F(2, 1377) = 35.93,pb .001 in the number of hospitalizations, with posthoc tests showing significant differences among all threeconditions.

Regarding which variables represented confounds,the three variables were correlated. Number of hospi-talizations was most strongly associated with outcomes.After controlling for it, only age of illness onset wassignificantly associated with outcomes. Therefore, itwas decided to control for both number of pasthospitalizations as well as age of illness onset insubsequent analyses. Controlling for these variables didnot violate the homogeneity of regression slopesassumption for any of the primary outcome variables.

Table 2 presents the primary outcome means andfrequencies (in raw scores) for each group. The bipolar Iand II groups had significantly lower GAF scores,higher work impairment ratings, and significantly moresuicide attempts than the MDD group. GAF scores inthe bipolar I and II groups were in the upper end of the“serious symptoms” or “serious impairment” range,whereas the average range for the MDD group was atthe lower end of the “moderate symptoms” or “moderatedifficulty” range. Almost 3 in 5 patients with bipolar I

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disorder had missed over a year of work due to theirpsychiatric illness. The rate was 1 in 3 for patients withbipolar II disorder. In contrast, only about 1 out of every6 patients with MDD disorder had missed more than ayear of work due to psychiatric illnesses. With respect tosuicide attempts, almost 1 in 3 patients with bipolar I orII disorder had made at least ones serious (i.e., high riskof death) suicide attempt. The rate was significantlylower in the MDD group, (i.e., slightly more than 1 in10). The three groups did not differ in terms of theirsocial functioning, with over 60% of all 3 groupsreporting social functioning that corresponded with“good” or better. More patients with bipolar I disorderhad social functioning considered to be “grosslyinadequate,” although the difference was not significant.

Analyses described in Table 2 were repeated, thistime controlling for differences in number of hospita-lizations and age of illness onset. As before, there wereno group differences on social functioning. The maingroup effect on GAF scores was no longer significantafter controlling for confounds, F(2, 1376)= .63,p=.53. Similarly, the rates of serious suicide attemptswere no longer different between groups after control-ling for age of illness onset and hospitalizations, χ2(2)=.65, p=.73. The same was not true for work functioning.Even after controlling for differences in hospitalizationand age of illness onset, there was a significant maineffect for group on work functioning, F(2, 1376)=7.23,p=.001. Post hoc tests revealed that this was due to asignificant difference between the bipolar I and MDDgroup. There was no significant post hoc differencebetween the bipolar II and the other groups aftercontrolling for confounds.

4. Discussion

Considerable work has explored the psychosocialimpact of major depressive disorder and bipolar Idisorder, yet few studies have looked at psychosocialimpairment in bipolar II disorder. Given the growinginterest in the “soft” spectrum, more attention to theburden associated with these disorders is needed.Indeed, there is some evidence to suggest that majordepressive episodes, more common in bipolar IIdisorder, lead to greater impairment than hypomanicor manic episodes (MacQueen et al., 2000).

The present study compared psychosocial functioningassociated with bipolar II disorder to the functioning seenin the more widely studied conditions of bipolar I andmajor depressive disorder. We were careful to take intoaccount the possibility that impairment measures mayhave been confoundedwith current or lifetime depression.

Several findings emerged. First, the three conditionshad different effects on work functioning. Second, wefound that both bipolar disorders were associated withgreater hospitalizations than depression alone. Third,both bipolar I and II disorder were associated with agreater number of serious suicide attempts than majordepressive disorder. Finally, we found similar levels ofsocial functioning across the conditions. Overall, thepsychosocial impact associated with bipolar II disorderwas much more similar than it was different from theimpact associated with bipolar I disorder. There was noindication from the current results that bipolar I and IIdiffered with respect to the impact of depression. Rather,when differences existed between the two conditions,they could be accounted for by the higher rate ofhospitalization in the bipolar I group.

Before discussing implications from these findings,several limitations deserve mention. Our sampling wasnot random. Rather, all participants were outpatientsseeking treatment; therefore, these results may notgeneralize to other types of psychiatric practices (e.g.,inpatient settings). We also can not rule out the possi-bility that the impairment associated with bipolar IIdisorder may be due to a selection bias, given that moreseriously ill bipolar II patients are more likely to go intotreatment.

Our design was cross sectional, making our modelsof causation tentative. Indeed, our findings remainassociations between bipolar disorders and psychosocialconsequences rather than predictive models. It is notdefinite that bipolar disorders lead to more workimpairment; the opposite, though unlikely, may be thecase. The causal relationship between hospitalizations,age of illness onset and work impairment is similarlyuncertain. When we controlled for number of hospita-lizations, the bipolar I and II groups did not differ fromeach other. However, hospitalizations may simplyreflect the disorder's severity, so a model that controlsfor it before comparing work impairment across the twogroups may be inappropriate. Similarly, we cannot ruleout the possibility that a third variable, not measured inour study and not inherent to the bipolar diagnosis, wasthe cause of more serious impairment in the bipolargroups. We did not have a healthy, non-psychiatriccontrol group. This limitation is mitigated in part bystudies that have already shown that bipolar I and majordepressive disorder lead to impairment.

One final potential limitation of the current workinvolves our method of diagnosing groups. We madediagnoses based on DSM-IV criteria and using theSCID. While a widely used assessment instrument,serious concerns exist regarding the validity of DSM-IV

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criteria for hypomania as well as the validity of theSCID to diagnose these conditions (Akiskal andBenazzi, 2005). Specifically, the 4-day criteria forhypomania may not be empirically supported; more-over, the SCID's reliance on a mood skip-out may leadto misdiagnosis. The relevance for the current studyfrom these potential problems is that many participantsin the MDD group may in fact have belonged to thebipolar spectrum. Depending on the level of impairmentamong these possibly misdiagnosed participants, itcould have made the bipolar II group appear more orless impaired. Future work needs to carefully considerthat subgroups of MDD patients may in fact belong tothe bipolar spectrum by assessing hypomanic episodeslasting less than 4 days, that are antidepressants-induced, and by considering alternative assessmentmethods (cf. Akiskal and Benazzi, 2005).

One of the primary findings from the present studywas the high toll on work functioning associated withbipolar II disorder. One third of people with thecondition had missed over a year of work in the lastfive years due to the illness. The average amount of timepatients with bipolar II disorder were not working due totheir illness in the last 5 years was between 6 months anda year. These rates fall between the amount of time outof work associated with bipolar I disorder and thatassociated with major depressive disorder. Althoughthere was more absenteeism in patients with bipolar Idisorder, the difference appeared to be related entirely tothem having been hospitalized more frequently. Thework losses faced by patients with bipolar II disorder aresubstantial, particularly since our measure of absentee-ism was conservative and may represent an underesti-mate: it only counted days missed if it was specificallydue to psychopathology (rather than medical illness) andonly in those patients who were expected to work (i.e.,excluded students, retired people, etc.). A centralmessage from the present study, therefore, is that even“soft” bipolar disorders, specifically bipolar II disorder,lead to major impairment in people's ability to work.

In contrast to work functioning, we found noevidence that the disorders were associated withdifferences in social functioning. The small non-significant differences that exist suggest that even alarger sample size with more power would still fail tofind a major difference. Why the disorders lead todifferences in work but not social functioning is unclear.It may be that our measure of social functioning was notsensitive enough to detect smaller gradations infunctioning. Alternatively, it may simply be that workfunctioning is far less resilient to the effects of a mooddisorder than social skills and social bonds. Indeed, over

60% of all three groups reported “good” functioning orbetter in the last 5 years. An example anchor for thislevel of social functioning was “1 or 2 special friendsthat he saw from time to time and was fairly close to.”The lack of a healthy control group makes it hard toascertain whether all groups had moderate socialfunctioning or whether all groups equally suffered intheir social functioning from the effects of each disorder.

Bipolar II disorder was also associated with highrates of hospitalization and high rates of suicide attempt.Over 40% of the bipolar II group had been hospitalizedat least once compared to only 26% of the majordepressive disorder group. This was still less than thebipolar I group (over 70% had been hospitalized at leastonce). Perhaps most troubling, bipolar II disorder,similar to bipolar I disorder, was associated with ahigh rate of past serious suicide attempts. The rate ofattempts in bipolar II disorder (27%) was almost as highas in bipolar I disorder (33%). Moreover, these ratesreflect serious suicide attempts (i.e. attempts with a highrisk for death) rather than merely suicidal gestures thatmight not be lethal (e.g., self-harm gestures). This resultunderscores a major conclusion from the present work,namely, that it would be a mistake for clinicians topresume that bipolar II disorder involves less seriousconsequences compared to bipolar I disorder. It alsoconfirms that bipolar I and II disorder are moreimpairing than major depressive disorder alone.

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