The Development of the Informant Five-Factor Borderline Inventory

Abstract

Borderline personality disorder (BPD) is one of the most studied personality disorders and is associated with significant outcomes such as suicide. Although BPD is represented in DSM-5 as a categorical diagnosis, it may be better characterized dimensionally, such as from the perspective of the five-factor model of general personality (FFM). The Five-Factor Borderline Inventory (FFBI) assesses BPD from the perspective of maladaptive variants of FFM traits. Previous research suggests that informant-reports may increase the validity of personality disorder assessment, providing additional information that may supplement self-report. Therefore, the current study developed an informant measure of the FFBI, Informant Five-Factor Borderline Inventory (IFFBI) and examined its convergent and discriminant validity compared with the self-report FFBI, FFM, and traditional measure of BPD. Overall, the IFFBI demonstrated good convergent validity and moderate discriminant validity with the FFBI, FFM, and other traditional measures of BPD.

Keywords

borderline personality disorder informant report five-factor model dimensional model

Borderline personality disorder (BPD) is described in the American Psychiatric Association’s (APA, 2013) Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) as “a pervasive pattern of instability of interpersonal relationships, self-image, and affects, and marked impulsivity that begins by early adulthood and is present in a variety of contexts” (p. 663). DSM-5 BPD is diagnosed when individuals meet five of the nine diagnostic criteria. However, as noted extensively in the literature, there are many issues with the current diagnostic system, including arbitrary cutoffs, comorbidity within PDs, comorbidity with other psychological disorders, and heterogeneity of diagnoses (e.g., Clark, 2007; Lenzenweger et al., 2007; Tomko et al., 2014; Widiger & Trull, 2007).

Utilizing dimensional models to describe PDs may resolve some of these issues. PD researchers have recently proposed to conceptualize and assess all of the PDs dimensionally in both DSM-5 and the International Classification of Diseases, 11th Revision (ICD-11) (APA, 2013; Tyrer et al., 2011). There is a strong taxometric evidence supporting a dimensional conceptualization of BPD (Arntz et al., 2009; Rothschild et al., 2003; Trull et al., 1990). Among the various dimensional models of PDs, the five-factor model (FFM; McCrae & Costa, 2003) is the most prominent. The FFM consists of five dimensional domains of personality (neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness), with each domain containing six facets each as assessed by the NEO Personality Inventory–Revised (Costa & McCrae, 1992). Meta-analyses of the FFM-PD research studies have documented strong support for understanding the PDs from the perspective of the FFM (O’Connor, 2005; Samuel & Widiger, 2008; Saulsman & Page, 2004). Indeed, the dimensional trait models of both the DSM-5 Section III (Krueger & Markon, 2014) and the ICD-11 (Mulder et al., 2016) are both aligned with the FFM.

The initial meta-analytic review of PDs revealed that BPD can be characterized by high neuroticism, low agreeableness, and low conscientiousness (Saulsman & Page, 2004). Samuel and Widiger (2008) confirmed these findings and also specified which facets were significantly correlated with BPD. They found that all six facets of neuroticism (anxiousness, angry hostility, depressiveness, self-consciousness, impulsiveness, and vulnerability) were positively correlated with BPD while two facets (warmth and positive emotions) from extraversion, three facets (trust, straightforwardness, and compliance) from agreeableness, and four facets (competence, dutifulness, self-discipline, and deliberation) from conscientiousness were negatively correlated with BPD. Multiple studies have found that these relevant FFM traits capture the categorical BPD symptom counts very well (e.g., Miller et al., 2012; Trull et al., 2003).

Following the evidence that it is beneficial to conceptualize BPD as maladaptive variants of FFM traits, Mullins-Sweatt et al. (2012) developed a self-report measure, the Five-Factor Borderline Inventory (FFBI), assessing BPD traits using 11 facets from the FFM that are highly related to BPD. The FFBI consists of 12 subscales (FFM vulnerability is assessed by two subscales; Affective Dysregulation and Fragility). The 12 facets of the FFBI are anxious uncertainty, dysregulated anger, despondence, self-disturbance, behavioral dysregulation, affective dysregulation, fragility, dissociative tendencies, distrust, manipulativeness, oppositionality, and rashness. The scale contains a total of 120 items, with 10 items per subscale, and was validated with a large undergraduate student sample and a clinical sample in a residential treatment facility.

The FFBI subscales showed strong convergent validity with their corresponding FFM facets as well as discriminant validity with the other facets (Mullins-Sweatt et al., 2012). The results from the validation study also indicated that the FFBI showed significant incremental validity predicting the scores of other BPD measures over the corresponding FFM facets from the NEO-PI-R (Costa & McCrae, 1992). The total score of the FFBI also accounted for significant additional variance in the Personality Assessment Inventory BPD scale above and beyond other BPD measures, such as the OMNI Personality Inventory–IV (Loranger, 2001).

DeShong et al. (2015) further validated the FFBI by again confirming its relationships with both measures of general personality and traditional measures of BPD using two samples of students who previously had engaged in nonsuicidal self-injury. DeShong and colleagues also reported strong relationships with constructs associated with BPD, such as emotion dysregulation, impulsivity, and early childhood emotional vulnerability. DeShong et al. (2016) subsequently developed and validated the short form of the FFBI (FFBI-SF) through item response theory analyses. The subscales of the short form also illustrated significant convergent and discriminant validity when compared with existing measures of BPD, FFM, and the FFBI. Additional validation and/or research application of the FFBI has been provided by Grove et al. (2017), Crego et al. (2018), and Tucker et al. (2016).

Although self-report measures are most often used in the assessment of BPD, this method is not without limitations. Self-report provides only one source of information, which may include biases. This may be pertinent in PD diagnoses especially, since individuals with PD may have distortions of self-perception (Oltmanns & Turkheimer, 2009). Therefore, informant reports can provide complementary information that can aid in the assessment of PDs. In fact, self-report and informant-reports of personality pathology are moderately correlated, at best. In a recent meta-analysis, median correlation between self–other PD ratings was .37 and the median correlation for BPD, specifically, was .44 (Oltmanns & Oltmanns, 2019).

Research suggests that informant reports can also have incremental validity above and beyond self-report of personality for certain outcomes. Observer ratings of the FFM contributed significant additional variance beyond the self-reports of personality in predicting overall job performance, whereas self-report was not incrementally valid above and beyond the informant reports (Oh et al., 2011). Informant-reported FFM PD scores contributed to a significant increase in variance for borderline, paranoid, antisocial, histrionic, and avoidant PDs (Miller et al., 2004). Also, Balsis et al. (2015) found that informant reports of FFM and PDs were more internally consistent than the self-reports and informant reports predicted global measures of health better than self-report measures.

One of the features of BPD is identity disturbance. Those diagnosed with BPD show poor awareness of their own values and goals (Linehan, 1993), have difficulty predicting future behaviors (Damman et al., 2011), and have difficulty predicting how they are perceived by others (Carlson & Oltmanns, 2015). If one is unaware of who one is or if one’s sense of self changes regularly, the self-report assessment of personality traits can become rather challenging; hence, informant-report may be useful in providing more nuanced and stable trait descriptions.

Despite their apparent usefulness, informant-reports are underutilized in PD research, reflecting in part perhaps the additional costs of identifying and recruiting informants. However, these issues can be easily addressed in recruitment methodology outlined by Vazire (2006). Another limitation to informant research is the lack of validated informant measures of PDs. While other informant measures for BPD exist, none assess BPD within a dimensional personality trait framework, which may be a better way to conceptualize and assess PDs. The PID-5 informant measure has been validated but the validation of PID-5 scale only includes the domain and facets of the PID-5 and not the validation of trait scores for PDs (Markon et al., 2013). This need for a new dimensional informant assessment of PDs utilizing personality trait framework is highlighted by the recent development of a measure for narcissistic PD, the Informant Five-Factor Narcissism Inventory (Oltmanns et al., 2018), Therefore, the current study seeks to aid the research of BPD by developing an informant measure of BPD using the maladaptive traits of FFM (Informant Five-Factor Borderline Inventory [IFFBI]). The current study assesses convergent and discriminant validity of the IFFBI. Specifically, the IFFBI subscale and total scores were correlated with their corresponding FFBI self-report subscales and total scores, International Personality Item Pool–NEO–120 (IPIP-NEO-120) facet scores, and Multisource Assessment of Personality Pathology (MAPP) BPD scores to examine convergent validity. The IFFBI subscale and total scores were also correlated with noncorresponding FFBI subscales, IPIP facets, and MAPP PD subscale scores to examine discriminant validity.

Method

Participants

Six hundred and eighty-five students from Oklahoma State University participated in the study and received course credit. Participants were 71.2% female and 78% Caucasian. The average age of the participants was 19.47 years (standard deviation [SD] = 2.16), ranging from 18 to 41 years.

Informants

Up to three informants were recruited for each participant. All informant participation was voluntary. Informants were not compensated for their participation. After their participation, the informants were debriefed in accordance with the requirements of institutional review board at Oklahoma State University. Most informants (85.3%) reported that they knew targets “extremely well” (M = 4.82, SD = 0.49) on a 5-point scale from 1 (not at all) to 5 (extremely well). Informants indicated that the average length of their relationship with targets was 13.76 years (SD = 7.56), ranging from 2.5 months to 28 years. Informants were 71% female and 77.8% Caucasian. The average age of the informants was 37.32 years (SD = 15.03). The majority of the informants were parents (55%), 28.4% of the informants were friends, 7.3% were partners, and 9.3% were other relationships.

Five hundred and fifty informants consented to participate. The appendix outlines the manner in which participants and informants were included in the study. Two informants were removed based on their reported response validity. Missing data rates for IFFBI, MAPP, and IPIP were calculated and informants who did not complete 80% on any one of the three measures were not included in the analyses. One informant response was removed due to duplicate identification numbers. Three hundred and thirty-three informant responses remained for analyses. Informants’ responses were averaged for those who responded regarding the same target participant, resulting in 247 informant response sets. These merged informant response data were matched with participant data, resulting in 214 participant–informant matched data used for analyses in the study.

Procedures

The participants were recruited through the online SONA psychology participant pool. The nine items of the PDQ-4 BPD scale (Bagby & Farvolden, 2003) were used as a prescreener from January 2018 to May 2018. From August 2018 to January 2019, 10 MSI-BPD (Zanarini et al., 2003) items were used as a prescreener. Those who endorsed five or more items on either scale were invited via e-mail as outlined above (approximately 20% of the sample who completed the PDQ-4+ endorsed five or more items). The study though was also open to everyone within the SONA pool. Participants were provided with a link to complete the study online using Qualtrics online survey tool. Once the participants consented to participate, they were asked to provide contact information of up to three informants who knows them very well. For each informant, the participant provided the nature of the relationship, ranked how well the informants knew the participant, and described how long they have known each other. Following this, the participants completed demographic questionnaires and other measures. On completion of measures, the participants received a debriefing document including the purpose and the intent of the study, and SONA credits as compensation.

Informants were contacted for recruitment via e-mail and phone. Informants were provided with a personalized link to their email to participate in the study. The link provided a brief introduction to the study, the voluntary consent form, and the measures. The informants received the link up to 3 times with each link expiring within 14 days. From September to December of 2018, informants were also contacted via phone before sending the recruitment e-mail to increase response rates. On completion of the study, the informants were debriefed.

Measures

Demographics Questionnaire

Several relevant demographic variables were collected via self-report questionnaire. The demographics questionnaire was collected from both the participants and the informants. These questions included the target participant age, gender, ethnicity, religious affiliation, and income level. The target participants and informants also indicated how long they have been acquainted, how often they talk to each other (5-point Likert-type scale), how well they know each other (5-point Likert-type scale), and if they have been in contact in the past 30 days.

Five-Factor Borderline Inventory

The FFBI (Mullins-Sweatt et al., 2012) is a 120-item self-report measure that assesses BPD from the perspective of the FFM. The FFBI contains a total score and 12 subscale scores that correspond to respective facets. For example, FFBI Anxious Uncertainty corresponds to the FFM anxiousness facet from the neuroticism domain. Each item is rated on a 5-point Likert-type scale from 1 (Strongly Disagree) to 5 (Strongly Agree). In the current study, coefficient alphas for each facet ranged from .74 (oppositional) to .92 (Self-Disturbance), with coefficient above .80 for 11 of the 12 scales. Coefficient alpha for the total score was .95.

Informant Five-Factor Borderline Inventory

The IFFBI is a 120-item informant-report measure. The items were revised from first to third person without deleting any items. The items have 5-point Likert-type scale ranging from 1 (strongly disagree) to 5 (Strongly agree), as the original FFBI form. The FFBI consists of 12 subscales (anxious uncertainty, dysregulated anger, despondence, self-disturbance, behavioral dysregulation, affective dysregulation, fragility, dissociative tendencies distrust, manipulativeness, oppositionality, and rashness). Internal consistency of the IFFBI subscales ranged from α = .83 to α = .92, and overall internal consistency of the measure was α = .98. All IFFBI subscales were moderately to highly correlated with other IFFBI subscales and the IFFBI total score.

International Personality Item Pool–NEO–120

The IPIP-NEO-120 (Maples et al, 2014) is a 120-item self-report measure that assesses the five domains and 30 facets of the FFM. The IPIP-NEO-120 was developed using item response theory and is rated on a 5-point Likert-type scale from 1 (disagree strongly) to 5 (agree strongly). Internal consistency of the IPIP domains ranged from .79 (Openness to Experience) to .90 (Neuroticism). Cronbach’s alpha for facets ranged from .51 (Self-Consciousness) to .90 (Depression).

International Personality Item Pool–NEO–120 (Informant Version)

The items from the IPIP-NEO-120 were converted from first person to third person for the informant version as instructed by the IPIP website. Cronbach’s alpha for domains in the current study ranged from .82 (Openness to Experience) to .93 (Conscientiousness). Internal consistency for facets ranged from .65 (Modesty) to .91 (Deliberation).

Multisource Assessment of Personality Pathology

The MAPP (Oltmanns & Turkheimer, 2006) is a self-report measure of 80 items that assesses the 10 PDs in the DSM-IV-TR. It is rated on a 5-point Likert-type scale from 0 (I am never like this/0% of the time) to 4 (I am always like this/100% of the time). Balsis et al. (2015) reported the Cronbach alpha for the self-report, which ranged from .57 (Schizoid) to .81 (Avoidant). Cronbach’s alpha from the current study ranged from 0.61 (Schizoid) to 0.85 (Borderline).

Multisource Assessment of Personality Pathology–Informant

The MAPP informant report (MAPP-I; Oltmanns & Turkheimer, 2006) version of 80 items assess 10 PDs in the DSM-IV-TR on a 5-point Likert-type scale from 0 (He/she is never like this/0% of the time) to 4 (He/she is always like this/100% of the time). Cronbach’s alpha ranged from .58 (Schizoid) to .84 (Narcissistic and Borderline) in the current study.

Personality Inventory for DSM-5 Short Form (PID-5-SF)

The PID-5-SF (Maples et al., 2015) is a 100-item self-report measure that assesses pathological personality trait model of the alternative model of PDs in Section III of the DSM-5. The PID-5-SF assesses five domains and 25 facets of the pathological personality trait model (negative affectivity, detachment, psychoticism, antagonism, and disinhibition). The items are rated on a 5-point Likert-type scale from 0 (very false or often false) to 3 (very true or often true). The Cronbach alpha of the five domains ranged from .85 (Antagonism) to .90 (Negative Affectivity). Cronbach’s alpha of the facets ranged from .51 (Manipulativeness) to .90 (Depressivity and Distractability).

Personality Inventory for DSM-5 Short Form–Informant (PID-5-SF-I)

The 100 items of PID-5-SF were converted from first person to third person for the informant version, with permission from the author of the PID-5, Dr. Robert Krueger. The PID-5-SF informant version assesses five domains and 25 facets of the pathological personality trait model. The items are rated on 5-point Likert-type scale from 0 (Very False or Often False) to 3 (Very True or Often True). Internal consistency of PID-5-SF domains in the current study ranged from .82 (Antagonism) to .93 (Negative Affectivity).

Personality Diagnostic Questionnaire 4+ (PDQ-4+)

The PDQ-4+ (Hyler, 1994) consists of 99 true/false items that assess DSM-IV-TR PDs. Cronbach’s alpha from the current study ranged from .47 (Obsessive–Compulsive) to .73 (Avoidant).

Missing Data Analysis

Within merged data, subscale scores for all measures were calculated. Then, multiple imputation was conducted on the subscale scores using mice package (Van Buuren & Groothuis-Oudshoorn, 2011) in R (R Core Team, 2018). Total scores of scales were calculated using the imputed scores.

Results

IFFBI and FFBI

A series of correlational analyses between IFFBI facet scores and FFBI subscale scores revealed good convergent validity (see Table 1). The total score of IFFBI was significantly correlated, r(213) = .40, p < .001, with FFBI total score, as expected. All IFFBI subscales were significantly correlated with their corresponding FFBI subscales in the expected direction: range, r(213) = .26, p < .001 for Behavior Dysregulation to r(213) = .44, p < .001 for Despondence. Most IFFBI subscales had the highest correlation with their corresponding FFBI subscales and lower correlations with other subscales of the FFBI (i.e., Anxious Uncertainty, Despondence, Dissociative Tendencies, Distrust, Manipulation, Oppositionality, and Rashness), demonstrating good discriminant validity. Five of the subscales though (Dysregulated Anger, Self-Disturbance, Behavioral Dysregulation, Affect Dysregulation, and Fragility) correlated as strongly or more strongly with other neuroticism-related FFBI subscales. IFFBI Self-Disturbance also had a higher correlation with FFBI Distrust, r(213) = .32, p < .001, than its corresponding subscale, r(213) = .29, p < .001. IFFBI Behavioral Dysregulation subscale had higher correlation with FFBI Rashness, r(213) = .29, p < .001, than its corresponding FFBI subscale, r(213) = .26, p < .001.

Table 1.

Correlation Between IFFBI and FFBI facets.

FFBI	IFFBI
FFBI	Anx Uncertain	Dysreg Anger	Desp.	Self-Disturb	Behav Dysreg	Affective Dysreg	Fragility	Dissoc Tend	Distrust	Manip	Opp	Rash	Total
Anx. Uncertain.	0.41	0.21	0.33	0.25	0.21	0.31	0.37	0.21	0.25	0.13	0.19	0.13	0.30
Dysreg. Anger	0.17	0.27	0.24	0.17	0.14	0.22	0.20	0.18	0.21	0.11	0.23	0.13	0.24
Despond.	0.40	0.26	0.44	0.34	0.28	0.36	0.44	0.33	0.30	0.20	0.20	0.16	0.38
Self-Disturb	0.32	0.24	0.36	0.29	0.23	0.31	0.34	0.31	0.28	0.16	0.17	0.22	0.33
Behav. Dysreg	0.20	0.27	0.29	0.24	0.26	0.26	0.30	0.28	0.22	0.21	0.20	0.16	0.31
Affective Dysreg	0.34	0.31	0.41	0.31	0.29	0.36	0.39	0.29	0.26	0.21	0.23	0.26	0.36
Fragility	0.33	0.25	0.41	0.31	0.27	0.33	0.43	0.33	0.26	0.19	0.20	0.21	0.36
Dissoc. Tend.	0.22	0.26	0.30	0.24	0.22	0.27	0.28	0.34	0.20	0.16	0.17	0.20	0.29
Distrust.	0.28	0.20	0.32	0.32	0.20	0.26	0.27	0.22	0.34	0.18	0.18	0.14	0.29
Manip.	0.14	0.21	0.22	0.22	0.20	0.20	0.23	0.25	0.21	0.26	0.20	0.23	0.26
Opp.	0.15	0.25	0.27	0.27	0.18	0.21	0.17	0.22	0.22	0.15	0.28	0.21	0.26
Rash.	0.12	0.27	0.24	0.24	0.29	0.22	0.23	0.23	0.17	0.27	0.23	0.37	0.29
Total	0.34	0.32	0.42	0.33	0.28	0.36	0.41	0.34	0.32	0.24	0.28	0.26	0.40

Note. All correlation analyses were significant with p < 0.001. Anx. Uncertain. = Anxious Uncertainty; Dysreg. Anger = Dysregulated Anger; Desp. = Despondence; Self-Disturb. = Self-Disturbance; Behav. Dysreg. = Behavioral Dysregulation; Affective Dysreg. = Affective Dysregulation; Dissoc. Tend. = Dissociative Tendencies; Distrust. = Distrustfulness; Manip. = Manipulativeness; Opp. = Oppositional; Rash. = Rashness. FFBI = Five-Factor Borderline Inventory; IFFBI = Informant Five-Factor Borderline Inventory.

IFFBI and IPIP

A series of correlational analyses between the IFFBI subscale scores and IPIP informant domain and facet scores revealed good convergent validity (Table 2). All IFFBI subscales were significantly correlated with their corresponding IPIP facets: range, r(213) = .50, p < .001 for IFFBI Dissociative Tendencies with IPIP Imagination to r(213) =.78, p < .001 for IFFBI Despondence with IPIP Depression. Five of the IFFBI subscales (Anxious Uncertainty, Dysregulated Anger, Despondence, Oppositionality, and Rashness) presented good discriminant validity, where the subscale’s correlation with the corresponding IPIP facet was the highest compared with its correlation with noncorresponding IPIP facets. However, seven of the IFFBI facet scores had equal or higher correlations with a noncorresponding facet than their corresponding facets. Specifically, five subscales of the IFFBI had higher correlations with IPIP Depression (Self-Disturbance, Behavioral Dysregulation, Affect Dysregulation, Fragility, and Dissociative Tendencies) than their corresponding facets.

Table 2.

Correlation of IFFBI With IPIP Informant Domains and Facets.

IPIP	IFFBI
IPIP	Anx. Uncertain	Dysreg Anger	Desp	Self-Disturb	Behav Dysreg	Affect Dysreg	Fragility	Dissoc Tend	Distrust	Manip	Opp	Rash
Neuroticism	0.75	0.70	0.70	0.71	0.63	0.71	0.68	0.55	0.58	0.50	0.57	0.53
Anxiety	0.76	0.52	0.6	0.58	0.43	0.55	0.55	0.42	0.5	0.3	0.39	0.35
Anger	0.51	0.77	0.47	0.44	0.50	0.62	0.43	0.30	0.44	0.44	0.61	0.45
Depression	0.73	0.63	0.78	0.74	0.58	0.68	0.72	0.56	0.62	0.49	0.48	0.46
Self-Consc	0.34	0.24	0.31	0.47	0.29	0.29	0.29	0.26	0.29	0.16	0.10	0.22
Immoderation	0.38	0.41	0.38	0.42	0.48	0.4	0.43	0.46	0.32	0.39	0.45	0.41
Vulnerability	0.62	0.60	0.56	0.57	0.59	0.66	0.62	0.53	0.42	0.47	0.5	0.54
Extraversion	−0.29	− 0.21	− 0.24	−0.37	− 0.18	−0.24	− 0.24	− 0.21	−0.26	−0.10	−0.11	−0.17
Friendliness	−0.31	−0.26	− 0.27	−0.37	− 0.19	− 0.24	− 0.25	− 0.19	−0.36	−0.11	− 0.23	−0.16
Gregarious	−0.16	−0.01	−0.08	−0.15	0.04	0.00	−0.07	−0.08	−0.13	0.10	0.08	0.03
Assertiveness	−0.17	−0.13	−0.17	−0.32	− 0.20	− 0.23	−0.18	− 0.21	−0.14	−0.10	−0.04	− 0.22
Activity	−0.28	−0.29	−0.29	−0.38	−0.36	−0.34	−0.30	−0.34	−0.18	−0.3	− 0.22	−0.34
Excitement Seek	−0.01	0.08	0.04	0.00	0.20	0.10	0.04	0.12	0.02	0.19	0.13	0.20
Cheerfulness	−0.34	−0.37	−0.39	−0.45	−0.35	−0.37	−0.38	− 0.25	−0.4	− 0.27	− 0.27	− 0.26
Openness to Experience	0.20	0.08	0.21	0.09	0.14	0.18	0.17	0.29	0.09	0.10	0.11	0.09
Imagination	0.25	0.19	0.27	0.27	0.28	0.26	0.24	0.50	0.16	0.22	0.2	0.28
Artistic Interests	0.02	−0.09	0.01	−0.11	−0.06	−0.02	0.03	0.03	−0.06	−0.09	−0.1	−0.15
Emotionality	0.45	0.31	0.37	0.30	0.31	0.39	0.39	0.29	0.32	0.17	0.23	0.23
Adventurousness	−0.28	−0.18	−0.12	−0.21	−0.07	−0.11	−0.10	−0.07	−0.20	−0.03	−0.08	−0.05
Intellect	0.02	−0.08	0.03	−0.09	−0.16	−0.11	−0.03	0.05	−0.01	−0.11	−0.06	−0.17
Liberalism	0.22	0.15	0.25	0.23	0.21	0.23	0.21	0.28	0.16	0.18	0.18	0.14
Agreeableness	−0.36	−0.63	−0.39	−0.47	−0.57	−0.56	−0.44	−0.37	−0.49	−0.66	−0.72	−0.53
Trust	−0.41	−0.37	−0.35	−0.34	−0.29	−0.37	−0.36	−0.24	−0.62	− 0.21	−0.40	−0.17
Morality	−0.34	−0.49	−0.37	−0.45	−0.63	−0.51	−0.44	−0.40	−0.35	−0.73	−0.55	−0.38
Altruism	−0.27	−0.47	−0.29	−0.39	−0.40	−0.43	− 0.28	− 0.26	−0.30	−0.46	−0.51	−0.38
Cooperation	−0.39	−0.70	−0.45	−0.49	−0.59	−0.59	−0.45	−0.35	−0.42	−0.64	−0.74	−0.56
Modesty	0.03	− 0.23	0.05	0.00	−0.19	−0.14	−0.07	−0.03	−0.08	−0.34	−0.32	−0.20
Sympathy	−0.01	− 0.19	−0.08	−0.18	−0.15	−0.13	−0.08	−0.14	−0.13	− 0.22	− 0.25	−0.17
Conscientiousness	−0.40	−0.51	−0.47	−0.57	−0.64	−0.58	−0.53	−0.51	−0.38	−0.56	−0.53	−0.64
Self-Efficacy	−0.41	−0.49	−0.44	−0.55	−0.60	−0.57	−0.52	−0.50	−0.36	−0.51	−0.46	−0.60
Orderliness	− 0.22	−0.30	− 0.26	− 0.28	−0.38	−0.34	−0.30	−0.32	− 0.22	−0.31	−0.33	−0.39
Dutifulness	−0.39	−0.54	−0.47	−0.56	−0.70	−0.60	−0.51	−0.48	−0.39	−0.76	−0.56	−0.68
Achievement Striving	−0.29	−0.41	−0.36	−0.47	−0.52	−0.47	−0.4	−0.41	− 0.27	−0.45	−0.44	−0.54
Self-Discipline	−0.44	−0.47	−0.45	−0.53	−0.53	−0.53	−0.43	−0.46	−0.35	−0.44	−0.44	−0.54
Cautiousness	−0.38	−0.53	−0.43	−0.51	−0.67	−0.56	−0.50	−0.50	−0.40	−0.60	−0.55	−0.73

Note. Boldfaced values p < .001; underlined values p < .01. N = Neuroticism; A = Agreeableness; O = Openness, C = Conscientiousness; E = Extraversion; Anx. Uncertain. = Anxious Uncertainty; Dysreg. Anger = Dysregulated Anger; Desp. = Despondence; Self-Disturb. = Self-Disturbance; Behav. Dysreg. = Behavioral Dysregulation; Affective Dysreg. = Affective Dysregulation; Dissoc. Tend. = Dissociative Tendencies; Distrust. = Distrustfulness; Manip. = Manipulativeness; Opp = Oppositional; Rash. = Rashness; IFFBI = Informant Five-Factor Borderline Inventory; IPIP = International Personality Item Pool.

IFFBI and Other Measures of PDs

A series of correlation analyses between IFFBI and MAPP PD scales revealed good convergent and discriminant validity (see Table 3). The IFFBI total score was significantly correlated with participant-reported MAPP BPD, r(213) = .39, p < .001, and informant-reported MAPP BPD, r(213) = .77, p < .001. IFFBI illustrated moderate discriminant validity, as it showed the highest correlation with the participant-reported MAPP Borderline subscale compared with other MAPP subscales. However, IFFBI showed moderate and significant association with self-reported MAPP histrionic, r(213) = .37, p < .001, and schizotypal subscales, r(213) =.35, p < .001. IFFBI also exhibited lower correlations with other informant-reported PDs, ranging from r(213) = .00, p = .99 for obsessive–compulsive PD to r(213) = .61, p < .001 in the informant-reported MAPP, highlighting good discriminant validity with informant-reported MAPP subscales.

Table 3.

Correlations Between IFFBI Total Score and MAPP PD Scores.

MAPP scales	Self-reported MAPP	Informant-reported MAPP
Borderline	0.39***	0.77***
Paranoid	0.26***	0.45***
Schizoid	0.11	0.09
Schizotypal	0.35***	0.48***
Histrionic	0.37***	0.58***
Narcissistic	0.16^*	0.61***
Antisocial	0.29***	0.60***
Avoidant	0.18**	0.51***
Dependent	0.20**	0.51***
Obsessive–Compulsive	.07	0.00

Note. IFFBI = Informant Five-Factor Borderline Inventory; MAPP PD = Multisource Assessment of Personality Pathology personality disorder.

p < .01. ^***p < .001.

Correlational analyses between the IFFBI and PID-5 PD composite scores were also conducted (Table 4). The Alternative Model for Personality Disorders (AMPD; APA, 2013) proposed a novel, trait-based PD diagnostic system. Within the AMPD, six PDs are described by associated pathological personality traits and impairment in personality functioning. The PID-5 assesses the 25 pathological personality traits in AMPD. The current study created PID-5 PD composite scores by adding up the pathological personality traits score from the PID-5 that described each PD in the AMPD. Therefore, six PD composite scores were created for both self-report PID-5 and informant-report PID-5 for analyses, as outlined in Samuel et al. (2013).

Table 4.

Correlations Between IFFBI Total Score and Self-Reported PID-5 PD Composite Scores.

Self-PID-5 composite	Self-reported PID-5	Informant-reported PID-5
Borderline	0.42***	0.86***
Antisocial	0.30***	0.79***
Avoidant	0.33***	0.61***
Narcissistic	0.32***	0.75***
Obsessive–Compulsive	0.20**	0.48***
Schizotypal	0.36***	0.72***

Note. IFFBI = Informant Five-Factor Borderline Inventory; PID-5 PD = Personality Inventory for DSM-5 personality disorder.

p < .01. ^***p < .001.

The correlational analyses between the IFFBI and PID-5 PD composite scores revealed good convergent validity. As expected, the IFFBI scale score was moderately correlated, r(213) = .42, p < .001, with the self-reported PID-5 Borderline composite score, and highly correlated with the informant-reported PID-5 Borderline composite score, r(213) = .86, p < .001. The analyses revealed moderate discriminant validity with self-reported PID-5 PD composite scores, and mixed discriminant validity with the informant-reported PID-5 PD composite scores. Correlations between the IFFBI scale score and self-reported PID-5 PD composite scores ranged from r(213) = .21, p = .002 (Obsessive–Compulsive) to r(213) = .36, p < .001 (Schizotypal). Correlations between IFFBI scale score and informant-reported PID-5 PD composite scores ranged from r(213) = .48, p < .001 (Obsessive–Compulsive) to r(213) = .79, p< .001 (Antisocial). Correlations between IFFBI scale score and informant-reported Antisocial, r(213) = .79, p < .001; Narcissistic, r(213) = .75, p < .001; and Schizotypal, r(213) = .72, p < .001, were especially high.

Discussion

Issues of the current categorical diagnostic system of PDs issues have long been highlighted (e.g., Tomko et al., 2014; Lenzenweger et al., 2007). Researchers have suggested conceptualizing PDs with dimensional traits, highlighted by the AMPD in the DSM-5 and the ICD-11 proposals. Despite this effort, validated dimensional measures of PDs are limited. The FFBI (Mullins-Sweatt et al., 2012) is the only FFM dimensional measure of BPD.

Research also suggests that informant reports of personality and personality pathology are only moderately related to the self-reports but may also add incremental validity in predicting behavioral outcomes (e.g., Balsis et al., 2015; Miller et al., 2004; Oh et al., 2011). Despite the highlighted importance of researching and utilizing informant-reports of PDs, there is no validated dimensional informant personality trait measure of BPD. The current study addressed this gap in the PD informant literature by developing and validating the IFFBI, an informant measure of BPD using the maladaptive traits of FFM that complements the FFBI (Mullins-Sweatt et al., 2012).

The current study aimed to validate the IFFBI as a measure using convergent and discriminant validity with the FFBI, a general personality trait measure, and existing PD measures. As expected, convergent relationships between the informant-reported IFFBI and other self-reported constructs (i.e., FFBI, MAPP BPD, PDQ BPD, PID-5 BPD) were moderate, while the convergent correlation between IFFBI scale score and informant-reported constructs (i.e., MAPP Informant BPD, PID-5 Informant BPD) were high. This is consistent with previous self-informant agreement research, as Oltmanns and Oltmanns’s (2019) meta-analysis found moderate correlation between self-informant agreement on PD ratings. Overall, the IFFBI illustrated good convergent validity. However, discriminant validity was modest, especially for IFFBI subscales.

Consistent with our hypotheses, the IFFBI scale score was significantly correlated with the FFBI scale score while exhibiting smaller but significant correlations with FFBI subscales. The correlation between IFFBI and FFBI was moderate (r = .40), in line with self–other agreement of r = .44 for BPD found in a recent meta-analysis (Oltmanns & Oltmanns, 2019).

The IFFBI subscales illustrated good convergent validity but modest discriminant validity with the facets of the FFBI. This was more apparent with discriminant validity between an FFBI facet and other noncorresponding facets in the same domain. This same pattern emerged when examining discriminant validity between IFFBI subscales and IPIP-NEO facets. However, most instances of modest discriminant validity were due to higher correlation with other facets that are from the same domain and facets within a respective domain are expected to correlate. For example, IFFBI Fragility subscale had moderate correlation not only with FFBI Fragility subscale but also with a few other FFBI subscales that correspond to facets of FFM neuroticism (i.e., r = .44 with Despondence, r = .39 with Affective Dysregulation). This modest discriminant validity with general personality facet-level traits may provide additional insight into the distinct information provided by self- and informant-reports. It is also possible that informants tend to aggregate domain-level information but have difficulty in reporting facet-level information with sufficient distinction. This hypothesis requires further investigation.

The IFFBI total score also demonstrated excellent convergent and discriminant validity with self-report of MAPP, a symptom-based measure of PDs. As expected, correlations between IFFBI and self-reported MAPP BPD were modest and the only significant correlational relationship between IFFBI and self-report MAPP PD subscales. On the other hand, the IFFBI demonstrated good convergent validity with informant-reported MAPP BPD and modest discriminant validity with other informant-reported MAPP PDs. The IFFBI exhibited the highest correlation with informant-reported MAPP Borderline PD scale (r = .62). However, IFFBI was also highly correlated to informant-reported MAPP Histrionic, Narcissistic, and Antisocial PD subscales. This is consistent with previous research of categorical PDs that found high comorbidity between BPD, histrionic PD, and antisocial PD (Widiger & Rogers, 1989). Samuel and Widiger’s (2008) meta-analytic review of FFM facets and PDs reveal shared low agreeableness traits between narcissistic, borderline, and antisocial PD. Low agreeableness traits may account for the significant relationship between IFFBI, MAPP Narcissistic PD, and MAPP Antisocial PD. IFFBI Distrust, Manipulation, and Oppositionality subscales correspond to FFM trust, straightforwardness, and compliance facets which were all traits significantly correlated with borderline, narcissistic, and antisocial PD (Samuel & Widiger, 2008). This finding also may shed a light into personality traits that are accentuated through informants’ perception. Externalizing traits, more observable traits to the informants, may be highlighted in those with borderline, antisocial, narcissistic, and histrionic PD traits. Previous research also has found higher self-informant agreement on low agreeableness traits. For example, Sleep et al. (2019) found that antagonism (low agreeableness) had the highest self-informant agreement among the personality pathology domains based on the DSM-5 AMPD.

It is also important to note that reliability for self-reported and informant-reported MAPP subscales were lower than ideal. This may be due to dichotomizing the scale from Likert-type scale responses. Reliability was especially lower for MAPP Antisocial PD, which may be due to lack of antisocial PD symptom endorsements among the sample, with symptom scores ranging only from 0 to 1, out of 9.

The IFFBI illustrated good convergent validity with participant- and informant-reported PID-5 PD composite scores. The IFFBI demonstrated questionable discriminant validity with PID-5 PD composite scores, though this is in line with previous research on PID-5 traits that indicated poor discriminant validity of the PID-5 traits (Crego et al., 2015; Hopwood et al., 2012). Thus, modest discriminant validity between the IFFBI and PID-5 PD composite scores may be attributable to concerns with the PID-5.

In conclusion, the IFFBI demonstrated good convergent validity with the FFBI, traditional measure of PDs, and a measure of general personality. The IFFBI revealed moderate discriminant validity, especially at the subscale level. This moderate discriminant validity is not only consistent with previous literature on comorbidity of PDs but also allows insight into differing perception of traits between self and informant. The current study validates the IFFBI as an informant measure of BPD in the perspective of FFM.

Previous research examining informant measures of BPD only reported self-informant agreement for the categorical symptoms of BPD according to the DSM-IV. However, the IFFBI allows the administrator to understand maladaptive personality traits that are associated with BPD, providing more detailed and useful information to the administrator that can inform future research and clinicians. For research purposes, the IFFBI can be utilized to study informant research in BPD. Clinicians can utilize the measure to understand the maladaptive personality traits associated with BPD, and thereby to better inform treatment.

There are some limitations to the current study. First, the current results are based on one cross-sectional student sample. While the informants were from a mix of student and community samples, it would be important to replicate these findings in a community and/or clinical sample, including with clinicians and patients. Second, most of the participants (>50%) had only one informant response. For the participants that had more than one informant responses, the responses were averaged. This may have introduced some informant-specific bias in assessing the participants’ traits. Additionally, due to the limited number of informants per person, we were not able to examine the effect of certain types of informants (e.g., friend vs. family). If future studies collected data from both friends and family of the participants, how relationship type affects the self-informant agreement could be examined. However, it is also important to note that a number of the participants who completed the self-report measure did not have any corresponding informant reports so these data were not examined in the current study. Due to limited sample size, the current study did not conduct metric variance tests to compare the IFFBI and FFBI. Future studies should conduct metric variance tests and compare the means of IFFBI and FFBI. Finally, the incremental validity of the IFFBI relative to FFBI was not explored in this study. Exploring incremental validity of the IFFBI by utilizing self- and informant-reported functional impairment and other behavioral outcome scales would be important in future studies.

Footnotes

Appendix

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Stephanie N. Mullins-Sweatt

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