Annals of Indian Psychiatry

REVIEW ARTICLE
Year
: 2022  |  Volume : 6  |  Issue : 3  |  Page : 209--217

Differential profile of bipolar mood disorder, borderline personality disorder, and healthy controls using big five of personality: A meta-analysis of studies over a period of thirty years


Saeid Komasi 
 Department of Neuroscience and Psychopathology Research, Mind GPS Institute, Kermanshah, Iran

Correspondence Address:
Dr. Saeid Komasi
Department of Neuroscience and Psychopathology Research, Mind GPS Institute, Nasr Boulevard, 404 Mokhaberat, Kermanshah
Iran

Abstract

The present meta-analysis was performed to compare Five-Factor Model (FFM) personality factors between (i) patients with a bipolar mood disorder (BMD) and healthy controls (HC), (ii) patients with borderline personality disorder (BPD) and HC, and (iii) two diagnostic categories of BMD and BPD. The literature systematic search was performed on PubMed (Medline) for all articles published in English from January 1990 to June 2021 (PROSPERO-CRD42021267855). The pooled effect sizes were obtained by the standard mean differences (Cohen's d) between cases with BMD and BPD and HC using the random-effects method. Egger's test and I2 >50 were used to detect possible publication bias and heterogeneity, respectively. Due to the limited number of studies to compare FFM factors between these two diagnostic categories, we compared the standard z-scores extracted from two separate analyzes for each disorder. Eleven case-control studies were entered into the meta-analysis. The results show that there are significant differences between the two diagnostic categories and HC in all FFM factors, except openness for BMD. Based on z-scores, we found that the two diagnostic categories are different in neuroticism (BMD<BPD), extraversion (BMD>BPD), openness (BMD>BPD), and agreeableness (BMD>BPD). There was no difference between the two disorders in conscientiousness (P= 0.279). Our results suggest that profiles of personality factors distinguish BMD and BPD from HC and each other. Except for the conscientiousness factor, in other factors, BPD shows a greater tendency toward general personality psychopathology.



How to cite this article:
Komasi S. Differential profile of bipolar mood disorder, borderline personality disorder, and healthy controls using big five of personality: A meta-analysis of studies over a period of thirty years.Ann Indian Psychiatry 2022;6:209-217


How to cite this URL:
Komasi S. Differential profile of bipolar mood disorder, borderline personality disorder, and healthy controls using big five of personality: A meta-analysis of studies over a period of thirty years. Ann Indian Psychiatry [serial online] 2022 [cited 2022 Dec 1 ];6:209-217
Available from: https://www.anip.co.in/text.asp?2022/6/3/209/360070


Full Text



 Introduction



Bipolar mood disorder (BMD) is a common chronic disorder characterized by a combination of mania or hypomania with periods of depression.[1] This disorder is distinguished into two types I, including at least one period of mania, and II with at least one period of hypomania without any history of mania with periods of depression.[2] The prevalence of BMD in the world is 1%–5% reported.[3] Impulsive behaviors, violence and aggression, substance and alcohol abuse, suicidal thoughts and attempts, and an unhealthy lifestyle[4],[5] are among the most important consequences of this diagnostic category. Recent research literature has pointed to the role of several factors in the development and persistence of BMD. Biological factors include abnormalities in the prefrontal cortex, limbic system, hippocampus, and amygdale, environmental factors such as stressful events, physical and sexual abuse, emotional neglect or abuse, family history of mood disorders, especially in parents, underlying psychiatric factors such as conduct disorder, posttraumatic stress disorder, and psychotic symptoms, and personality factors such as high neuroticism and low extraversion have been reported as the most important underlying correlates.[3],[6],[7],[8],[9]

Although pervasive classification systems such as the diagnostic and statistical manual of mental disorders (DSM-5) and the International Classification Of Diseases-11 present BMD as a distinct diagnostic category from other mental disorders, the symptoms of this disorder show high overlap with other diagnostic categories of psychiatry, including borderline personality disorder (BPD).[10] BPD is characterized by instability in emotions and affect states, self-image, and interpersonal relationships that begin in early adulthood.[11] People with BPD, in addition to impulsive behaviors, violence and aggression, substance and alcohol abuse, and suicidal thoughts and attempts,[12],[13] suffer from emotional dysregulation and alexithymia[14],[15] and they cannot distinguish between what is going on in their minds and what is in reality.[16] The prevalence of BPD is estimated between 3% and 61% in the general and clinical population.[17],[18] Numerous theories and models related to the etiology of this diagnostic category emphasize the combination and interaction of biological factors and environmental experiences such as physical, sexual, and emotional abuse.[19],[20] Also, personality components are another important factor in the development of BPD. In the last decade, personality disorders have been conceptualized as maladaptive forms of normal personality traits[21] and several studies have suggested the role of high neuroticism and openness and low extraversion, agreeableness, and conscientiousness in the etiology and differential diagnosis of BPD.[22],[23]

As mentioned, BMD and BPD have many similarities, the most important of which is mood instability. Also, mood irritability and the occurrence of impulsive and high-risk behaviors in both disorders can make it difficult for clinicians to differentiate. Evidence shows that there is a strong relationship between these two diagnostic categories of psychiatry so that 10%–20% of patients with BMD have a comorbid BPD.[10] In confirmation of the strong association between the two disorders, the results of a study showed that the symptoms of BPD are more related to the symptoms of BMD than to unipolar depression.[24] Also, Perugi et al.[25] showed that interpersonal sensitivity and mood instability are common between BMD and BPD but not with depression. This relationship may overlap in etiological principles or some similar diagnostic criteria; Because Koenigsberg[26] shows that emotional instability in BPD is due to responsiveness to psychosocial trauma, while mood instability in BMD has an internal origin. Lack of family history of bipolar spectrum disorders, lack of symptoms of depression or hypomania, early onset in childhood and adolescence, higher prevalence in men, impaired emotion regulation rather than experiencing mood cycles, low response threshold to stressors and stress-related dissociative symptoms, twice the risk of suicide attempt, better response to treatment in women, and distinct personality patterns such as sensitivity to criticism in patients with BPD are the distinguishing features of this diagnostic category from BMD.[25],[26],[27],[28] Unlike patients with BMD who are more inclined to have stable relationships, patients with BPD showed more avoidance in relationships for fear of rejection.[25] However, bipolar spectrum symptoms worsen with age.[25] Of course, worse behavioral and therapeutic consequences are expected in case of comorbidity of these two disorders. These consequences include longer periods of depressed mood and more mood cycles,[26] increased likelihood of hospitalization and length of treatment, decreased quality of life, increased risk of substance abuse, withdrawal, and social and occupational dysfunction, cognitive disorders, and aggression and suicide.[10],[24],[26],[29],[30]

The common and differentiating antecedents and consequences of BMD and BPD have always made it difficult for clinicians to diagnose and treatment.[31] As mentioned above, several factors including biological, environmental, familial, and personality factors are involved in the etiology, prognosis, and treatment process of BMD and BPD. Among these, personality factors as the most basic and stable indicators have been the focus of some studies.[31],[32] In particular, the five-factor model (FFM) as the most influential and dominant personality model in contemporary psychology has been able to provide a practical and appropriate framework for the range of normal to abnormal personality traits proposed in the alternative personality disorders in the third part of DSM-5.[11],[33] FFM, consisting of five broad domains of neuroticism, extraversion, openness, agreeableness, and conscientiousness, is the dominant dimensional model in the overall structure of personality that has been able to partially solve the problem of boundary and differential diagnosis between the diagnostic categories of psychiatry.[34],[35] Previous studies in patients with BMD and BPD have reported relatively stable results based on high levels of neuroticism and low extraversion, agreeableness, and conscientiousness.[23],[36],[37] However, combining the samples and data of all studies into a meta-analysis can provide more accurate effect sizes for each of the FFM factors related to the diagnostic categories. Therefore, the present study aimed to compare the FFM factors among (i) patients with BMD versus healthy controls (HC); (ii) BPD versus HC; and (iii) BMD versus BPD.

 Methods



The present meta-analysis was registered in PROSPERO-CRD42021267855 and follows the instructions of the 27-item checklist of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).[38] The process included determining sources and databases, strategies for systematic search, selection criteria, quality assessment of articles, and data extraction.

Sources and databases

The population of the meta-analysis included all articles published in English for 30 years from January 1990 to June 2021. A systematic search was performed in PubMed (Medline; n = 376). Using a manual search of references, ten articles were found (total number: 386).

Search strategies and inclusion criteria for studies

Based on previous studies and reviews related to the present study's aims, the more suitable keywords for searches were determined. The systematic searches in the title/abstract were conducted using the selected keywords list. The keywords related to bipolar mood and borderline personality diagnoses and personality factors of the FFM were selected. The list of keywords was as follows: (”big-five model” OR ”five-factor model” OR ”FFM” OR ”NEO” OR ”NEO-FFI” OR ”agreeableness” OR ”conscientiousness” OR ”openness” OR ”extraversion” OR ”neuroticism”) (AND) (”bipolar disorder” OR ”bipolar mood disorder” OR “bipolar affective disorder” OR ”manic” OR ”mania” OR ”hypomanic” OR ”hypomania” OR ”BD-I” OR ”BD-II” OR ”borderline personality disorder” OR ”BPD” OR ”borderline personality”).

We wanted to include all studies presenting correlations between the big five factors of personality and BMD and BPD from 1990 to 2021. Thus, inclusion and exclusion criteria were determined. All English original articles (excluded n = 17) published in an academic journal containing participants 18 years and older (excluded n = 67) were entered into the review (n = 302). The exclusion criteria were the following: (a) papers not dealing with personality factors or bipolar and borderline disorders (n = 59); (b) book and conference abstracts, dissertations and unpublished papers, studies with nonoriginal data, included previous reviews and meta-analyses, experimental/interventional, longitudinal, correlation studies, and other studies with an unrelated or unsuitable design without reported differences at the baseline (n = 70); (c) papers not examining the link between personality factors and BMD and BPD (n = 38); (d) studies containing nonstandard self-report instruments without reported validity or tools theatrically unrelated to FFM (n = 38); (e) papers without a human sample (n = 49); (f) studies without HC or include normative controls (n = 28); (g) not applicable case–control without studies reported means difference (n = 9); and (h) low-quality reports (n = 0) based on STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) [Supplementary 1]–a; pages [Supplementary 1]–[Supplementary 2]. Thus, the present meta-analysis included 11 studies. The study selection procedure is observable in [Figure 1].[INLINE:1]{Figure 1}

Quality assessment of the studies and data extraction

The quality of studies was independently conducted by two authors (SK and DB) using the STROBE checklist.[39] This 22-item checklist evaluates the quality of the types of cross-sectional studies such as case–control and correlation studies. According to the current objectives, studies with a cut-off point of ten or fewer were excluded (Supplementary 1-b; page 3). However, the quality of all studies was higher than this cut-off point and none of them were excluded from the meta-analysis. The disagreement between the two researchers on the final quality score of each study was resolved by discussion with another author (MS).

To extract data, a table was designed to classify and record the collected data and information. After assessment of the quality of the selected studies (none of the articles were left out), the data from each study were entered into the systematic table designed for recording the research information. The process of data synthesis included tabulation and detailed descriptions of the findings of each study. The included studies were organized based on the first author's name and year of study, participants and country of data collection, sample size, mean age (standard deviation) or age range of the subjects, study design, statistical methods, data gathering tools, findings, limitations, and level of evidence.

Data synthesis and analysis

Several meta-analyses were performed to calculate the pooled effect size of the standardized mean difference (Cohen's d) of the FFM factors between cases with BMD or BPD and HC. Two studies did not report data related to openness or agreeableness for BPD. Therefore, instead of six studies, a meta-analysis was performed on five studies. The studies were combined based on sample size, mean, and standard deviation of the FFM factors in the cases and controls. Pooled effect sizes for group differences (cases vs. controls) are presented with 95% confidence intervals (95% CI).

Egger's test was used to detect possible publication bias. Heterogeneity (significant I2 or higher than 50%) was found in 80% of the FFM factors. Thus, pooled estimates of the standardized mean difference were calculated for both diagnostic categories using the random-effects method.[40] We studied the heterogeneity of the study samples using the I2 statistics for a 95% CI. A P < 0.05 for I2 higher than 50% was considered a significant heterogeneity. Given the importance of comparing personality traits between BMD and BPD diagnostic classes and the limited number of studies to perform analysis, the pooled standardized mean differences obtained from case–control studies were transformed into the standard z scores. All hypotheses were tested at the P < 0.05 and performed using the comprehensive meta-analysis 2 software.

 Results



Studies included in the meta-analysis

Systematic literature and manual search provided 386 papers. Eventually, 11 papers including 1636 (1103 female vs. 533 male; 375 BMD vs. 739 HC; 255 BPD vs. 275 HC) participants were entered into the meta-analysis. The study selection process based on PRISMA is shown in [Figure 1]. The results of the quality evaluation of articles using the STROBE checklist can be seen in Supplementary 1-b. The quality of 100% of the articles was medium and higher. The quality of studies ranged from 11 to 17 and the median and mean were 14 and 13.9, respectively. Each of the FFM factors associated with BMD and BPD was examined in five studies, except for neuroticism, extraversion, and conscientiousness related to BPD, which was examined in six studies. These studies were conducted in the Germany (n = 5), USA (n = 2), UK (n = 1), Switzerland (n = 1), Japan (n = 1), and Brazil (n = 1). The summary of the methods/results of the studies and the extracted information can be seen in [Table 1]. The Publication bias was not observed for any of the FFM factors (P > 0.05 for Egger's statistic). The publication bias and heterogeneity can be seen in [Table 2].{Table 1}{Table 2}

Five-factor model factors in the bipolar mood disorder compared to healthy controls

[Figure 2]a presents the standardized mean difference between cases and controls in FFM factors. The effect sizes in a pooled forest plot with 95% CI and significance levels are presented for each factor. As can be seen, there is a significant difference between BMD and HC in neuroticism (d = 1.175, P < 0.001), extraversion (d = −0.307, P = 0.049), agreeableness (d = −0.392, P < 0.007), and conscientiousness (d = −0.478, P = 0.008). Although, there was no difference between the two groups in openness (d = 0.057, P = 0.622).{Figure 2}

Five-factor model factors in the borderline personality disorder compared to healthy controls

[Figure 2]b presents the standardized mean difference between cases and controls in FFM factors. The effect sizes in a pooled forest plot with 95% CI and significance levels are presented for each factor. As can be seen, there is a significant difference between cases with BPD and controls in the neuroticism (d = 2.266, P < 0.001), extraversion (d = −1.310, P < 0.001), openness (d = −0.578, P < 0.001), agreeableness (d = −0.831, P < 0.001), and conscientiousness (d = −0.912, P = 0.026).

Five-factor model factors in the bipolar mood disorder compared to borderline personality disorder

[Figure 2]c presents the significant differences between BMD and BPD in FFM factors using comparing the standard z scores. The figure show that the two diagnostic categories are different in the neuroticism (BMD < BPD, P < 0.001), extraversion (BMD > BPD, P < 0.001), openness (BMD > BPD, P < 0.001), and agreeableness (BMD > BPD, P < 0.001). There was no difference between the two disorders in the conscientiousness (BMD = BPD, P = 0.279). [Figure 2]c also shows the differential diagnosis of BMD from BPD by the standard z scores in FFM factors.

 Discussion



The present meta-analysis was performed to compare the big five personality traits in three groups of patients with BMD or BPD and HC. In general, the results showed a vulnerable personality profile in both clinical groups, especially BPD, compared to HC. Although in the period of this meta-analysis, few studies have compared the personality traits of patients with BMD and BPD,[31] our indirect analyzes indicated a more vulnerable personality profile (excluding the conscientiousness factor) in BPD. Also, higher scores on the conscientiousness factor for BPD challenge the likelihood of these two diagnostic categories being on the same continuum of psychopathology. However, the failure to directly compare personality traits between patients with BMD and BPD and the failure to report comorbidities in the few available studies makes it difficult to rule out or confirm this.

In more detail, the results of the present study indicated that patients with BMD have higher neuroticism and lower extroversion, agreeableness, and conscientiousness compared to HC. This indicates a disturbed personality profile related to the BMD, which poses a significant risk of diagnosing a personality disorder.[45] According to the present results, the largest effect size was related to the neuroticism factor, which in patients with BMD indicates a readiness to experience maladaptive negative emotions such as anger and hostility, anxiety and fear, shame, and sadness.[37] The low conscientiousness factor was the second important component associated with BMD that could explain noncommitment to personal tasks such as failure therapy.[51] Recent studies support the relationship between the disinhibition domain as the opposite pole of conscientiousness and the symptoms of bipolar spectrum disorders.[52] Also, the relationship between detachment and antagonism (as the opposite pole of extraversion and agreeableness) and bipolar spectrum disorders has recently been mentioned.[52]

Our results showed that patients with BPD reported higher neuroticism and lower extroversion, openness, agreeableness, and conscientiousness compared to HC. This finding indicates a more abnormal personality profile in patients with BPD that can explain their poor intrapersonal and interpersonal functions.[53] Similar to patients with BMD, neuroticism or emotional liability showed the strongest tendency toward abnormality among all five personality factors. This finding indicates the pivotal role of neuroticism in the onset and persistence of BPD and its associated pathological behaviors.[44],[54],[55] According to our findings, low levels of extraversion component is the second factor most strongly associated with BPD. The study of Hemmati et al.[56] confirmed the positive relationship between the detachment domain (especially anhedonia and withdrawal) as the opposite pole of extraversion and the symptoms of BPD. The negative relationship between other factors of the big five model including openness (vs. psychoticism), agreeableness (vs. antagonism), and conscientiousness (vs. disinhibition) and BPD may also be explained using their opposite poles; because recent studies have identified hostility, impulsivity, risk-taking, and perceptual dysregulation as elements of the BPD algorithm.[54],[55],[57]

Consistent with previous reports,[23],[58],[59],[60] the present results confirmed a more vulnerable personality profile in BPD compared with BMD. In more detail, our results show that patients with BPD report higher neuroticism and lower extroversion, openness, and agreeableness. Previous reports have indicated a more severe tendency for BPD on the spectrum of neuroticism.[58],[59] Other studies have suggested the combined role of high neuroticism and low extraversion and agreeableness in the more severe abnormality of BPD on the continuum of psychopathology.[23],[60] People with higher neuroticism are more vulnerable to stress and, in addition to more intense emotional reactions and emotional dysregulation, are shy and impulsive and have poor interpersonal skills.[61],[62] Therefore, these people are at high risk of developing psychopathology or more severe types of mental disorders.[63] On the other hand, impulsivity as a lower-order factor of neuroticism in BPD is more severe and stable than BMD, which can justify higher scores of neuroticism in this diagnostic category.[28] Conversely, the lack of significant differences between BPD and BMD in the conscientiousness factor may be explained by similar genetic mechanisms and the etiology of these two diagnostic categories.[31],[64]

Methodological considerations and limitations

In the present meta-analysis, the use of case–control studies containing samples with a definite diagnosis of BMD and BPD could provide valuable findings. Almost all of the studies included in the present meta-analysis had a sectional design, not longitudinal. Therefore, it is not possible to infer a causal relationship between FFM factors and the psychopathology of these two diagnostic categories. The main limitation of the current meta-analysis was the small number of articles related to BMD and BPD. Part of this was due to our lack of access to databases such as Web of Science and Scopus. Future reviews can provide more information by searching these databases and reduce the risk of bias in results. A larger limitation was the limited number of studies comparing FFM factors between BMD and BPD. We found only one study comparing personality traits between the two disorders.[31] Therefore, we were not able to directly compare personality traits between the two diagnostic categories and used standard z-scores. However, this method may increase the likelihood of bias in the results. Another limitation is a comorbidity in mental disorders. Psychiatric disorders are not usually pure and are comorbid with other disorders at the same time.[65],[66] The reason for this may be a complex relationship between personality traits and psychiatric disorders. In the present meta-analysis, some studies included in the analysis did not screen for co-occurrence of BMD and BPD with other diagnostic categories. The co-occurrence of these disorders with other psychiatric conditions may cause bias in research findings and conclusions. Therefore, future studies should focus on the analysis of BMD and BPD without comorbidity with other disorders. Another problem was that the mood of bipolar patients was not reported when completing the questionnaires related to the FFM in most studies entered into the analysis. Although personality as a separate factor may be less influenced by mood, controlling this may provide more accurate results. In the current meta-analysis, due to the small sample size, the FFM factors of men and women were not analyzed separately. Given that the results of case–control studies are influenced by gender differences, separate analyses can prevent potential biases. Based on these considerations, future studies can provide valuable results by overcoming the challenges in the current study.

 Conclusions



The FFM personality profiles distinguish BMD and BPD from HC and each other. The clinical groups show an unhealthy personality profile compared to HC (except for openness for BMD), which could explain part of the dimensional psychopathology of the diseases. The present results indirectly confirmed a more vulnerable personality profile (except conscientiousness) in the BPD compared with BMD. If further studies are available, future meta-analyses can directly compare FFM personality factors between these two diagnostic categories.

Financial support and sponsorship

This study was conducted with the financial support of the Mind GPS Institute of Kermanshah (ID: MGPSI-1400-A-1).

Conflicts of interest

There are no conflicts of interest.

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