ORIGINAL ARTICLE

Personality disorder comorbidity amongpatients with bipolar I disorder in remission

Tamam L, Ozpoyraz N, Karatas G. Personality disordercomorbidity among patients with bipolar I disorder in remission.Acta Neuropsychiatrica 2004: 16:175–180. # Blackwell Munksgaard2004

Background: Comorbid personality disorders have been shown to be aprominent factor affecting symptom severity and course in bipolardisorder (BD) patients. Bipolar patients with personality disorder hadmore relapses, poorer prognosis and worse treatment response thanthose without an axis II diagnosis.Objective: We evaluated the prevalence rate of comorbid personalitydisorder in 74 bipolar I disorder cases who were in remission and triedto elucidate the possible relationship between comorbid axis IIdisorders and prognosis, severity and treatment features of BD cases.Methods: Diagnosis of all personality disorder comorbidities wasevaluated using the Structured Clinical Interview for DSM-III-R Axis-II Disorders (SCID-II), while the general psychopathology level wasassessed using the Symptom Check List (SCL-90-R). A questionnairefor acquiring sociodemographic and clinical variables was also used.Results: Sixty-two per cent of bipolar I patients in this sample had atleast one comorbid axis II disorder. The most common comorbidcluster of personality disorder was cluster C (48.6%), followed bycluster A (25.7%) and cluster B (20.3%) personality disorders.Assessment of demographic and clinical variables revealed that bipolarpatients with comorbid personality disorder were mainly female, hadmultiple affective episodes, and had attempted suicide more often thanpatients without personality disorder.Conclusions: The results of this study suggest that comorbidpersonality disorder might alter the course of BD and result in a poorerprognosis and more severe psychopathology. Further prospectivecontrolled studies minimizing the bias of interviewers and otherconfounding factors would help us to understand the pure impact ofpersonality disorder on the course of BD, its prognosis and response totreatment.

Lut Tamam, Nurgul Ozpoyraz, GoncaKaratas

Cukurova University Faculty of Medicine, Department of Psychiatry,

Adana, Turkey

Keywords: bipolar disorder; comorbidity; personality disorder;

SCID

Correspondence: Lut Tamam MD, Cukurova Universitesi Tip

Fakultesi, Psikiyatri Anabilim Dali, 01330 Balcali, Adana,

Turkey. Tel: 90-533-6306006; Fax: 90-322-3386505;

E-mail: Ltamam@mail.cu.edu.tr

Introduction

The identification of comorbid personality traitsor disorders in patients with mood disorders hasreceived considerable attention in recent years(1–5). Although the major focus of studies regard-ing comorbid personality disorders were initiallyon depression, studies searching for the relationshipbetween bipolar disorder (BD) and personality dis-order (PD) have been on the increase during thelast decade (5–18). The presence of comorbid

PD has been shown to be a prominent factoraffecting symptom severity and course in BDpatients. Along with its phenomenological contri-bution, the association between PD and BD hasimportant practical therapeutic implications, asprevious research has reported relatively morerelapses, poorer prognosis and worse treatmentresponse in BD cases with comorbid PD (11–13,19). A greater prevalence of PD in bipolar patientswith multiple affective episodes has also been

Blackwell Munksgaard 2004: 16: 175–180 Copyright # Blackwell Munksgaard 2004

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# Blackwell Munksgaard, Acta Neuropsychiatrica, 16, 175–180 175

observed as compared with patients experiencingtheir first episode (10, 11).

The previous studies about comorbidity of PDin BD patients reported different rates of PD,ranging from 3 to 70% (1–3,5–10,20). In apioneering study, Charney et al. (2) found a rateof 23% of PD among bipolar patients during thedepressed phase based on case note reviews.Others, conducted in early 1990s, reported comor-bidity rates as low as 3% (5–7). In two recentstudies conducted with the Structured ClinicalInterview for DSM-III-R personality disorders(SCID-II), Barbato and Hafner (1) reported that45% of bipolar I patients met criteria for an axis IIdiagnosis, while Flick et al. (21) found the preva-lence rate of PD in BD to be as high as 70%. Thesedifferences in prevalence rates of PD comorbiditymay be due to the varying methodologies used forthe assessment of PD, i.e. using self-reportedscales, case notes or standardized instruments.Another reason for controversial results in theprevalence rate of PD may be the differences inthe clinical status or episode of the patient at thetime of assessment for PD (13). Leverich et al. (22)reported a higher incidence of axis II comorbiditiesin bipolar patients who were in manic or depres-sive episode compared with euthymic bipolarpatients. Apart from the discrepancy in prevalencerates of comorbid PD in several studies, there arealso conflicting results concerning the most com-mon cluster of PDs. Some studies suggested clusterC PD (i.e. avoidant, obsessive-compulsive, depend-ent, passive-aggressive) to be the most commoncomorbid PD group in BD cases (12,20) whileothers (15,16) noted cluster B PD group (i.e.borderline, histrionic, antisocial and narcissistic)to be more prevalent.

The purpose of this study was to determine theprevalence rate of comorbid PD in BD cases whoare in remission and to find out the possible rela-tionship between comorbid axis II disorders andprognosis, severity and treatment features of BDcases.

Methods

All patients presenting at bipolar disorder out-patient clinics of Cukurova University MedicalFaculty Department of Psychiatry in Adana, Turkey,between 1999 and 2001 were considered forinclusion in the present study. Patients treated andfollowed up in this unit were recruited from thosewho applied for treatment and received the diag-nosis of BD at the outpatient psychiatry clinics ofBalcali Hospital Cukurova University (a tertiary

level health institute which receives referrals fromthe southern part of Turkey) and also fromself-referrals.

Among patients enrolled in this unit, the oneswho met the following inclusion criteria wereincluded in the study: (i) age at least 18 years;(ii) DSM-III-R diagnosis of BD-I; (iii) beingclinically in remission for at least 1 month beforeinclusion in the study as corroborated by routinelyadministered scales during follow-up visits[Hamilton Depression Scale (HAM-D) and BechRafaelson Mania Scale scores of less than 7 for atleast 1 month in two consecutive visits were used asconfirmative scores for remission]; and (iv) writteninformed consent obtained before participation inthe study. The diagnosis of BD-I was madeclinically according to DSM-III-R criteria onadmission of the patient to the follow-up routineof outpatient clinics, and later confirmed byinterviews conducted by LT at the time of thestudy. Patients with another BD subtype diagnosis(i.e. BD-II, BD not otherwise specified andschizoaffective disorder, bipolar type), with a life-time history of organic mental disorder or uncon-trolled or serious medical disease and patientswith BD-I diagnosis but unwilling to cooperatewith the investigators were excluded from thestudy. Among 172 cases who were enrolled inour BD outpatient clinic at the time of the study,74 patients (31 male, 43 female) aged between 18and 64 years, fulfilled the inclusion criteria for thestudy. At the time of assessment, all subjects weretaking mood stabilizers (mainly lithium, followedby sodium valproate and carbamazepine) atadequate doses to maintain a euthymic state. Inaddition, six patients were on additional anti-psychotic treatment at minimal doses (threepatients on olanzapine 2.5 mg/day, one on halo-peridol 2.5 mg/day, and two on risperidone 1 mg/day). None were using antidepressants and inall cases serum blood levels of mood stabilizerswere within normal limits at the time of assessmentduring maintenance treatment.

Sociodemographic and clinical variables of thesubjects, including previous hospitalizations, num-ber and type of previous episodes, presence ofpsychotic features, suicide attempts, seasonalityand age at onset of the disorder, were obtainedfrom in-patient and outpatient medical records ofthe cases, patient interviews, and from first-degreerelatives when available. All scales and structuredinterviews were administered when patientswere in remission from any kind of affective epi-sodes to avoid any confounding factors that mightbe associated with episodes and to increasereliability.

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Diagnosis of all personality disorder comor-bidities was evaluated with the Structured ClinicalInterview for DSM-III-R Axis-II Disorders(SCID-II) by LT (23). General psychopathologylevel was assessed using the Symptom Check List(SCL-90-R) (24).

The chi-square test and Fisher’s exact test wereused to analyse categorical variables; t-tests wereperformed for continuous variables. All P-valueswere two-tailed and statistical significance was setat P< 0.05. All analyses were conducted withSPSS version 10.0 for Windows.

Results

Seventy-four patients (31 males, 43 females) with aDSM-III-R diagnosis of BD-I were included inthis study. Current mean age for the study groupwas 33.3� 10.7 years. Sociodemographic and clin-ical characteristics of the patients are presented inTable 1. Table 2 details frequencies of comorbidDSM-III-R PDs present in the sample. Forty-sixpatients (62.2%) had at least one comorbid PD.

The most common comorbid PD cluster was clus-ter C (48.6%), followed by cluster A (25.7%) andcluster B (20.3%) PDs. Eleven patients (14.9%)had both clusters A and C, five patients (6.8%)had clusters B and C, and four (5.4%) had clustersA, B and C PDs. The most prevalent PD in thewhole group was obsessive-compulsive PD(41.9%, n¼ 31). Schizoid, dependent and passive-aggressive PDs followed in decreasing order(Table 2).

The differences between BD-I patients with andwithout PD in terms of sociodemographic andclinical variables are presented in Table 3. FemaleBD-I patients had a significantly higher percentageof comorbid PD than male patients (72% [n¼ 31]vs. 48% [n¼ 15]; w2¼ 4.30 d.f.¼ 1, P¼ 0.038). Theprevalence of comorbid PD in multiple episodeBD-I cases was significantly higher than first-episode cases. BD-I cases with comorbid PD hada significantly higher rate of suicide attempts, com-pared with BD-I cases without comorbid PD (26vs. 7%, P¼ 0.044). The age at onset of the disor-der was lower in BD cases with a comorbid PD,but did not reach statistical significance with aclose margin (P¼ 0.057). The presence of a comor-bid PD in BD-I patients was not associated withother demographic and clinical variables studied,including the number of manic or depressiveepisodes, number of psychiatric hospitalizations,history of alcohol/substance abuse and seasonality.

Discussion

The results of the present study revealed that 62%of BD-I patients in this sample had at least onecomorbid axis II disorder. This rate is congruentwith the prevalence rates reported in existingstudies conducted with SCID-II. Prior studiesreported PD comorbidity in bipolar patients upto 70% (1,3,7,12,20). Peselow et al. (13) notedan interaction between personality traits and affec-tive episodes, especially hypomanic states, citingthe evidence that patients may describe themselvesas having greater maladaptive traits during periodsof acute psychopathology than during asymptom-atic episodes. To avoid such interaction andminimize the effect of confounding factors, wealso assessed the patients when they were euthymicand free of any affective disorders. In two of therecent studies with similar methodology andsample structure, Ucok et al. (20) found that48% of euthymic BD-I cases have at least oneDSM-III-R PD, whereas Leverich et al. (22),reported a PD comorbidity rate of 58% amongeuthymic BD-I patients.

Table 1. Sociodemographic and clinical characteristics of bipolar i patients

n %

SexMale 31 41.9Female 43 58.1

First-episode cases 12 16.3Multiple-episode cases 62 83.8Education level

Elementary 10 13.5Secondary 29 39.2Higher education 35 47.3

Marital statusMarried 33 44.6Single/divorced 41 55.4

Psychiatric history in first degree-relativesBipolar disorder 13 15.7Schizophrenia 2 2.9Other disorders 15 21.4Alcohol abuse or dependence 25 33.8

History of alcohol/substance abuse 13 17.6Presence of psychotic features 28 37.8Presence of suicide attempts 14 18.9Seasonality 25 33.8

Mean � SD Range

Current mean age (years) 33.3� 10.7 18–64Mean age at onset of the disorder (years) 23.2� 8.1 13–50Mean time period since onset of the disease (years) 10.3� 8.7 1–37Number of previous hospitalizations 2.3� 2.0 0–13Number of previous episodes 3.4� 1.9 1–8Number of previous manic episodes 2.3� 1.4 1–6Number of previous depressive episodes 0.9� 0.8 0–4

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The majority of cases comprising our studygroup had cluster C PD diagnosis as an axis IIdisorder (48%). While this finding was in line withresults of several recent studies (12,20), it was notconsistent with some of the other studies reportingcluster B PDs (particularly borderline and histrionicPD) as the most common comorbid PDs in BDcases (10, 11, 16). In this study, obsessive-compulsivePD (42%) was the most frequent PD at a rate atleast two times that of any other PD. Schizoid(19%), dependent and passive-aggressive PD (18%each) were other common comorbid PDs in oursample. Ucok et al. (20), similarly in a sample of90 Turkish bipolar patients, reported obsessive-compulsive PD as the most frequent comorbid PDin bipolar I cases, which may be a reflection ofcommon cultural aspects of the samples. The most

common comorbid PD in another study among 71bipolar patients (3) was also obsessive-compulsivePD, followed by borderline PD (32.4 and 29.6%,respectively). On the other hand, several other stud-ies conducted among bipolar II patients and amixed group of bipolar samples reported borderlinePD as the most prevalent PD (13–15). Possiblybecause of the different sample structure comprisingonly bipolar I cases, the rate of comorbid borderlinePD in this study (8.1%) was lower than thosereported rates (12.5–32%).

Rossi et al. (3) emphasized that, since by defini-tion a PD requires an onset no later than earlyadulthood and likely before an overt onset of amood disorder, the presence of obsessoid and/orborderline personality traits could be suggestive ofunnoticed bipolarity in some cases. Although wewere not able to define the exact onset of comorbidsituations, higher obsessive-compulsive PD comor-bidity in the present study might be confirmativeof the possibility of such an association. In astudy searching for PD among relatives of BDpatients (8), only obsessive-compulsive PD wassignificantly more common among relatives ofbipolar probands compared with relatives of acontrol group (6.3 vs. 2.2%). Maier et al. (8) con-cluded that the findings, along with augmentedscores of rigidity, provided evidence for a familiallink between bipolar affective disorder and obses-sional personality traits. Although we did not searchfor such an association, the relatively higher obses-sive-compulsive PD rate in our sample might alsorepresent a possible genetic predisposition withinBD-I cases.

Table 2. Prevalence of DSM-III-R personality disorders in bipolar I patients in remission

n %

Any personality disorder (PD) 46 62.2Any cluster A PD 19 25.7

Paranoid 12 16.2Schizoid 14 18.9Schizotypal 2 2.7

Any cluster B PD 15 20.3Histrionic 5 6.8Borderline 6 8.1Narcissistic 11 14.9Antisocial 4 5.4

Any cluster C PD 37 50Obsessive-compulsive 31 41.9Avoidant 11 14.9Dependent 13 17.6Passive-aggressive 13 17.6

Table 3. Sociodemographic and clinical illness variables for bipolar I patients with and without comorbid personality disorder

Comorbid PD (þ)(n¼ 46)

Comorbid PD (–)(n¼ 28) Analysis

Current age (years) 34.5� 10.0 31.3� 11.5 t¼ 1.26, d.f.¼ 72, P¼ 0.213Age at onset of the disease (years) 22.7� 7.6 24.0� 8.9 t¼ 1.93, d.f.¼ 72, P¼ 0.057Time period since onset of the disorder (years) 11.8� 8.9 7.9� 7.8 t¼�0.69, d.f.¼ 72, P¼ 0.492Number of previous hospitalizations 2.6� 2.2 1.9� 1.7 t¼ 1.51, d.f.¼ 72, P¼ 0.134Number of previous episodes 3.7� 1.8 2.9� 1.8 t¼ 1.85, d.f.¼ 72, P¼ 0.067Number of previous depressive episodes 0.98� 0.95 0.75� 0.75 t¼ 1.08, d.f.¼ 72, P¼ 0.285Number of previous manic episodes 2.4� 1.5 2.1� 1.2 t¼ 1.06, d.f.¼ 72, P¼ 0.293Sex (female) (n, %) 31 (67.4%) 12 (42.9%) w2¼ 4.30, d.f.¼ 1, P¼ 0.038Marital status (single) (n, %) 24 (52.2%) 17 (60.7%) w2¼ 0.51, d.f.¼ 1, P¼ 0.473First-episode cases (n, %) 3 (25%) 9 (32.1%) Fisher’s exact test, P¼ 0.007Multiple episodes (n, %) 19 (75%) 43 (66.9%)History of alcohol/substance abuse (n, %) 8 (17.4%) 5 (17.9%) Fisher’s exact test, P¼ 1.00Presence of psychotic features (n, %) 15 (32.6%) 13 (46.4%) w2¼ 1.41, d.f.¼ 1, P¼ 0.235Previous suicide attempts (n, %) 12 (26.2%) 2 (7.1%) w2¼ 4.07, d.f.¼ 1, P¼ 0.044Seasonality (n, %) 14 (41.3%) 11 (39.3%) w2¼ 0.61, d.f.¼ 1, P¼ 0.435Presence of psychiatric history inFirst-degree relatives (n, %)

19 (41.3%) 11 (39.3%) w2¼ 0.029, d.f.¼ 1, P¼ 0.864

Symptom Check ListGlobal Severity Index 0.97� 0.58 0.42� 0.32 t¼ 4.65, d.f.¼ 72, P< 0.0001

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Several significant differences in demographicand clinical variables were found between BD-Icases with and without comorbid PD. In the pre-sent study, bipolar patients with comorbid PDwere mainly female, had multiple affective epi-sodes, and had attempted suicide more oftenthan patients without PD. Earlier age at onset ofbipolar disorder is also observed in the presentpopulation, but the difference did not reach statis-tical significance with a close margin (P¼ 0.057).Some studies link early onset to worse outcome inBD and unipolar samples (15, 25). Another studydid not find any link between these variables (12).The association between lower age of onset andPD has been explained with two different possibil-ities: PD could lead patients to be more vulnerableto affective disorders or, alternatively, the earlieronset of affective disorder might disrupt thepersonality structure and cause long-lasting PD(10, 15).

Another approach to assessing the relationshipbetween BD and PD could be to compare the ratesof PDs in patients experiencing a first manic epi-sode (which is a prerequisite for a diagnosis of BD)with rates in patients with multiple affective epi-sodes (10). Despite our low number of first-episode cases, which should be borne in mind asa limitation (n¼ 12), there was a significant differ-ence between first and multiple episode cases withregard to PD prevalence. We observed PDs to besignificantly more common in multiple episodecases (70%) than in first-episode cases (25%)(P¼ 0.007), which is consistent with Dunayevichet al.’s findings (10, 11). This finding may partiallysupport the hypothesis that the personality traitsor disorders may have developed over time as aconsequence of affective disorders. Coryell et al.(26) suggested that repeated affective episodes andthe resulting dysregulation would predispose thepatient to the development of maladaptive person-ality traits that would in turn become part ofenduring psychological sequelae.

Patients with PD in this study had attemptedsuicide more often than those without PD, a find-ing consistent with other studies reporting moresuicidial behaviour or attempts in BD cases withPD (15, 20). Although other factors that are infor-mative about the outcome and course of the ill-ness, such as previous number of hospitalizations,previous number of affective episodes, psychoticfeatures, duration of illness and history of alcoholor substance abuse, did not show any significantdifferences between cases with and without PD, ahigher suicide attempt rate could still be anindicator of poorer outcome. In addition, in oursample, patients with PDs had a twofold higher

score on the Global Severity Index of SCL-90-Rthan patients without PDs, which indicated agreater severity of psychopathology and psychol-ogical impairment in this subgroup.

There are several methodological limitations ofthis study that should be mentioned and kept inmind during the interpretation of our results.First, this is a relatively small patient group froma BD outpatient unit of a university hospital,which prevents the generalization of the results toa whole community. Second, the study did notinclude a control group comprising non-BDcases, which precludes the comparison of thestudy group with a normal population, anothergroup with a different psychiatric illness, or othersubtypes of BD patients. Third, it was not possiblefor the authors to be entirely blinded to thepatients’ psychiatric history, which may havebiased the interviewers to diagnose more PD incases with multiple prior affective episodes and alonger known psychiatric disease course.

In conclusion, our findings suggest that bipolar Ipatients with a comorbid personality disorder tendto have multiple affective episodes, more suicideattempts, higher scores of psychopathology andrelatively earlier onset of illness compared withbipolar patients without axis II comorbidity.Future controlled studies focusing on gender dif-ferences, cultural variations and first-episode bipolarI cases will further improve our understanding ofpersonality comorbidity. Such controlled studieswill minimize the bias of interviewers and otherconfounding factors limiting our understandingof the pure impact of PD on BD course, prognosisand response to treatment.

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