Personality and Mental Health 8: 143–150 (2014) Published online 9 October 2013 in Wiley Online Library (wileyonlinelibrary.com) DOI 10.1002/pmh.1247
Comparison of affective instability in borderline personality disorder and bipolar disorder using a self-report measure
D. BRADFORD REICH1, MARY C. ZANARINI1, CHRISTOPHER J. HOPWOOD2, KATHERINE M. THOMAS2 AND GARRETT M. FITZMAURICE3, 1Laboratory for the Study of Adult Development, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA; 2Department of Psychology, Michigan State University, East Lansing, MI, USA; 3Laboratory for Psychiatric Biostastistics, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA ABSTRACT Background – This study used a new self-report instrument to measure frequency and intensity of nine dimensions of affective instability, as well as the extent to which affective instability was interpersonal, in subjects endorsing elevated features of BPD and bipolar disorder. Method – Subjects were 818 students enrolled in a state university. The study used self-report instruments to identify 21 participants with elevated features of mania and 30 subjects with significant BPD features. In addition, subjects completed a new self-report instrument to measure affective instability, the Affective Lability Questionnaire for Borderline Personality Disorder (ALQ-BPD). Results – Aggregate frequency and intensity scores, as well as the total scores on the ALQ-BPD, were significantly higher for subjects with elevated borderline traits than subjects with elevated bipolar traits. Subjects with borderline traits reported significantly more frequent affective shifts on seven of nine dimensions of the ALQ-BPD. Subjects with borderline traits reported significantly more intense affective shifts on two of nine dimensions. Both groups reported affective instability that was less than 50% reactive to interpersonal events, but subjects with borderline traits reported affective instability that was significantly more interpersonal than that reported by subjects with bipolar traits. Conclusion – The affective instability associated with symptoms of BPD and bipolar disorder has different profiles, particularly with respect to frequency. Borderline affective instability appears more interpersonal than the affective instability associated with bipolar symptoms. Copyright © 2013 John Wiley & Sons, Ltd. Introduction Research has suggested that affective lability is a feature of both bipolar disorder and BPD. Research on bipolar patients has found that they have more affective instability than normal comparison subjects,
Copyright © 2013 John Wiley & Sons, Ltd.
even during euthymic periods (Henri et al., 2008; M’Bailara, Demotes-Mainard, Swendsen, Leboyer, & Henry, 2009). Research on borderline patients has found that affective instability is a core feature of this disorder (Sanislow, Grilo, & McGlashan, 2000) and that the affective instability in BPD
8: 143–150 (2014) DOI: 10.1002/pmh
144
Reich et al.
differs from the affective instability in other personality disorders (Koenigsberg et al., 2002). Research using concurrent affective assessment has found increased affective instability in subjects with BPD compared both with healthy controls (HCs) and subjects with depressive disorders. One study, employing event-contingent recording, found that, compared with HCs, patients with BPD reported more variability of positive but not negative emotions (Russell, Moskowitz, Zuroff, Sookman, & Paris, 2007). A second study, using ecological momentary assessment (EMA), found that, over 24 h, borderline subjects reported more frequent shifts from sadness to anxiety, anxiety to sadness and anxiety to anger (Reisch, EbnerPriemer, Tschacher, Bohus, & Linehan, 2008). A third study used EMA to compare affective instability in borderline subjects and subjects with dysthymia or major depression. This study found that borderline subjects reported more variability of both positive and negative affect and that borderline subjects reported more instability with respect to hostility, fear and sadness (Trull et al., 2008). There has been disagreement over the relationship between affective instability in BPD and affective instability in bipolar disorder. One group of investigators has postulated a significant overlap between the two and has proposed that the affective instability in both disorders derives from a cyclothymic temperament (Perugi, Toni, Travierso, & Akiskal, 2003). A second group of investigators has asserted that there is a clear distinction between affective instability in the two disorders: affective instability in BPD tends to be more reactive and typically does not involve elation (Paris, Gunderson, & Weinberg, 2007). A recent study directly compared affective instability in subjects with BPD and subjects with bipolar II or rapid cycling bipolar disorders. To assess affective instability, that study used two selfreport instruments, the Affect Intensity Measure and the Affective Lability Scale, and a new clinician-administered instrument, the Affective Interview for BPD (ALI-BPD) (Reich, Zanarini,
Copyright © 2013 John Wiley & Sons, Ltd.
& Fitzmaurice, 2012). The study found that borderline and bipolar subjects reported significant differences in affective instability with respect to both intensity and frequency. Notably, borderline subjects reported more frequent affective shifts between depression and anxiety, as well as between euthymia and anger. In addition, they reported more intense affective shifts between the following: depression and anxiety, euthymia and anger and euthymia and anxiety. This study used a self-report instrument, the Affective Lability Questionnaire (ALQ)-BPD, to examine possible differences in affective instability between subjects with elevated borderline traits and subjects with elevated bipolar traits. Items in this instrument differ from those in the ALI-BPD in several ways. First, the ALQ-BPD does not include mood shifts involving elation, which should be more characteristic of a bipolar disorder. Second, the ALQ-BPD contains several items not contained in the ALI-BPD. These items include shifts between anger and depression and shifts between anger and anxiety. In addition, the ALQBPD contains an item asking subjects to rate the extent to which affective changes are responsive to treatment by others. Methods Participants Subjects were 818 university undergraduates who participated for class credit and completed questionnaires online. The sample was 71.5% female undergraduates (N = 585), and ages ranged from 18 to 47 years (mean = 19.96, median = 20.0, standard deviation (SD) = 2.52). Most of the sample (83.1%) was Caucasian, whereas 4.9% was Asian American and 3.2% African American. Evaluation procedure and instruments Subjects were evaluated diagnostically using the Personality Assessment Inventory Mania Scale (PAI-MAN) (Morey, 1991), the PAI Borderline Scale (PAI-BOR) (Morey, 1991), the Zanarini
8: 143–150 (2014) DOI: 10.1002/pmh
Affective Instability in BPD and BD
Rating Scale for BPD: self-report version (ZANBPD) (Zanarini, 2003) and the ALQ-BPD. The PAI-MAN is a 24-item measure of manic symptoms with a 4-point Likert Scale. The PAI-BOR is a 24-item measure of symptoms of BPD symptoms with a 4-point Likert Scale. The ZAN-BPD contains nine items corresponding to the nine DSM-IV criteria for BPD. Subjects rate each item on a 5-point Likert Scale. The ALQ-BPD is a 10-item questionnaire, designed to measure affective instability over the last week. The first nine items of the instrument measure affective instability in nine dimensions: euthymia–depression, euthymia–anger, euthymia– anxiety, depression–anxiety, anxiety–depression, anger–depression, depression–anger, anger–anxiety and anxiety–anger. Each item has two components, the first asking subjects to rate the frequency of affective shifts, and the second asking subjects to rate the intensity of shifts for that dimension. The frequency component of each item asks subjects to rate the frequency of affective shifts for that dimension on a 5-point Likert scale: 0, not at all; 1, once per week; 2, 2–3 times per week; 3, once per day and 4, more than once per day. The intensity component of each item asks subjects to rate the intensity of shifts in that affective dimension on a 4-point scale: 1, slight; 2, moderate; 3, very large shift and 4, severe. The tenth item on the ALQ asks subjects to rate the extent to which their mood shifts were reactive to the way that someone treated them on a 5-point scale: 1, almost never (0–10% of the time); 2, sometimes (11–35% of the time); 3, about half the time (36–65% of the time); 4, most of the time (66–90% of the time) and 5, almost always (91–100% of the time). The scores on each of the frequency items for questions 1–9 can be added to produce an overall frequency scale; the scores on each of the intensity of items for questions 1–9 can be added to produce on overall intensity scale. We classified subjects as bipolar if their score on the PAI-MAN was two SDs or more above the mean PAI-MAN score for this sample. We classified subjects as borderline if their score on the PAI-BOR was two SDs or greater than the mean PAI-BOR
Copyright © 2013 John Wiley & Sons, Ltd.
score for this sample. To be included in the analysis, subjects could not be classified with both bipolar disorder and BPD. Statistical methods Between-group differences were assessed using Wilcoxon’s rank sum test for: (1) ALQ-BPD scales constructed to measure overall frequency and overall intensity of affective instability; (2) individual intensity items on the ALQ-BPD; (3) individual frequency items on the ALQ-BPD and (4) subject ratings of how frequently their moods changed in response to how others treated them. The Wilcoxon’s rank sum test is relatively insensitive to skewness or extremes in the distribution of these scales; however, for ease of interpretation, summary statistics for each group are presented in terms of means and SD. To correct for multiple comparisons, p-values for comparisons involving individual items were adjusted using Hochberg’s procedure. To assess convergent validity, we used Spearman’s rho to obtain correlations between the sum of items 1–9 on the ALQ and the score of the item measuring affective instability on the ZAN-BPD. To assess reliability/internal consistency we computed Chronbach’s alpha separately for frequency and intensity items. Results In the study, 732 subjects completed the PAI-BOR, and 739 subjects completed the PAI-MAN. There were no significant differences in age or gender for subjects completing the PAI-BOR and PAI-MAN compared with subjects who did not complete these assessments. Twenty-one (2.8%) subjects in the sample completing the PAI-MAN met study criteria for bipolar disorder, and 30 (4.1%) subjects completing the PAI-BPD met study criteria for BPD. We excluded two subjects because they met criteria for both bipolar disorder and BPD. The mean age of subjects in the bipolar group was 19.4 years, and the mean age in the borderline group was 19.3 years. This
8: 143–150 (2014) DOI: 10.1002/pmh
145
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difference was not statistically significant. Thirteen subjects (68.4%) in the bipolar group and 24 subjects (88.9%) in the borderline group were women. This difference was not statistically significant. The Crohnbach’s alpha for all subjects completing the ALQ-BPD was 0.90 for frequency items and 0.88 for intensity items. The convergent validity of the ALQ, as assessed by the correlation between total ALQ lability scores and scores on the ZAN-BPD: self-report version affective instability item, was 0.50 (p < 0.001). The mean score on the ALQ-BPD frequency scale for subjects not classified as having either elevated BPD or bipolar features was 7.0 (SD = 5.7), qualitatively similar to the mean in the bipolar group. The mean score on the ALQ-BPD intensity scale was 8.9 (SD = 6.0), discernibly lower than the mean for the BPD and bipolar groups. Table 1 displays scores for ALQ frequency items for the borderline and bipolar groups. As seen in this table, borderline subjects reported significantly more frequent mood shifts in seven of the nine affective dimensions: euthymia– depression, euthymia–anxiety, euthymia–anger, anxiety–depression, depression–anxiety, depression–anger and anger-depression. Bipolar subjects
did not report more frequent shifts in any of the nine affective dimensions. For both groups, the most frequently reported affective shifts were between euthymia and depression. The Total Frequency Scale score was significantly greater for the borderline group, over twice as large as the score for the bipolar group. Table 2 details scores for ALQ intensity items for the borderline and bipolar groups. Borderline subjects reported significantly more intense affective shifts in only two dimensions; euthymia– depression and anxiety–depression. There was a trend for borderline subjects to report more intense shifts from euthymia into anxiety than those reported by bipolar subjects. As with frequency items, bipolar subjects did not report more intense shifts in any of the nine dimensions. The mean Total Intensity Scale score was significantly larger for borderline subjects, almost twice as large as the score for bipolar subjects. The mean score on the ALQ question 10, asking how frequently subjects believed their affective shifts occurred in reaction to how others treated them, was significantly greater for borderline than bipolar subjects (2.5 vs. 1.5, Z = 3.28, p = .001).
Table 1: Comparison of Affective Lability Questionnaire frequency scores for BPD and bipolar groups BPD (N = 28) Mean Total Frequency Scale Euthymia–depression Euthymia–anxiety Euthymia–anger Depression–anxiety Anxiety–depression Depression–anger Anger–depression Anxiety–anger Anger–anxiety
18.8 3.2 2.5 2.2 2.2 2.1 1.6 2.0 1.5 1.5
Bipolar (N = 19) SE
Mean
SE
1.4 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
7.7 1.2 1.0 1.0 0.9 0.7 0.6 0.7 0.9 0.7
1.3 0.2 0.3 0.2 0.2 0.3 0.2 0.2 0.3 0.3
Z-Scorea 4.43 4.65 3.76 3.31 3.74 3.39 3.20 3.67 1.65 2.19
p-valueb
Comparison of affective instability in borderline personality disorder and bipolar disorder using a self-report measure
D. BRADFORD REICH1, MARY C. ZANARINI1, CHRISTOPHER J. HOPWOOD2, KATHERINE M. THOMAS2 AND GARRETT M. FITZMAURICE3, 1Laboratory for the Study of Adult Development, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA; 2Department of Psychology, Michigan State University, East Lansing, MI, USA; 3Laboratory for Psychiatric Biostastistics, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA ABSTRACT Background – This study used a new self-report instrument to measure frequency and intensity of nine dimensions of affective instability, as well as the extent to which affective instability was interpersonal, in subjects endorsing elevated features of BPD and bipolar disorder. Method – Subjects were 818 students enrolled in a state university. The study used self-report instruments to identify 21 participants with elevated features of mania and 30 subjects with significant BPD features. In addition, subjects completed a new self-report instrument to measure affective instability, the Affective Lability Questionnaire for Borderline Personality Disorder (ALQ-BPD). Results – Aggregate frequency and intensity scores, as well as the total scores on the ALQ-BPD, were significantly higher for subjects with elevated borderline traits than subjects with elevated bipolar traits. Subjects with borderline traits reported significantly more frequent affective shifts on seven of nine dimensions of the ALQ-BPD. Subjects with borderline traits reported significantly more intense affective shifts on two of nine dimensions. Both groups reported affective instability that was less than 50% reactive to interpersonal events, but subjects with borderline traits reported affective instability that was significantly more interpersonal than that reported by subjects with bipolar traits. Conclusion – The affective instability associated with symptoms of BPD and bipolar disorder has different profiles, particularly with respect to frequency. Borderline affective instability appears more interpersonal than the affective instability associated with bipolar symptoms. Copyright © 2013 John Wiley & Sons, Ltd. Introduction Research has suggested that affective lability is a feature of both bipolar disorder and BPD. Research on bipolar patients has found that they have more affective instability than normal comparison subjects,
Copyright © 2013 John Wiley & Sons, Ltd.
even during euthymic periods (Henri et al., 2008; M’Bailara, Demotes-Mainard, Swendsen, Leboyer, & Henry, 2009). Research on borderline patients has found that affective instability is a core feature of this disorder (Sanislow, Grilo, & McGlashan, 2000) and that the affective instability in BPD
8: 143–150 (2014) DOI: 10.1002/pmh
144
Reich et al.
differs from the affective instability in other personality disorders (Koenigsberg et al., 2002). Research using concurrent affective assessment has found increased affective instability in subjects with BPD compared both with healthy controls (HCs) and subjects with depressive disorders. One study, employing event-contingent recording, found that, compared with HCs, patients with BPD reported more variability of positive but not negative emotions (Russell, Moskowitz, Zuroff, Sookman, & Paris, 2007). A second study, using ecological momentary assessment (EMA), found that, over 24 h, borderline subjects reported more frequent shifts from sadness to anxiety, anxiety to sadness and anxiety to anger (Reisch, EbnerPriemer, Tschacher, Bohus, & Linehan, 2008). A third study used EMA to compare affective instability in borderline subjects and subjects with dysthymia or major depression. This study found that borderline subjects reported more variability of both positive and negative affect and that borderline subjects reported more instability with respect to hostility, fear and sadness (Trull et al., 2008). There has been disagreement over the relationship between affective instability in BPD and affective instability in bipolar disorder. One group of investigators has postulated a significant overlap between the two and has proposed that the affective instability in both disorders derives from a cyclothymic temperament (Perugi, Toni, Travierso, & Akiskal, 2003). A second group of investigators has asserted that there is a clear distinction between affective instability in the two disorders: affective instability in BPD tends to be more reactive and typically does not involve elation (Paris, Gunderson, & Weinberg, 2007). A recent study directly compared affective instability in subjects with BPD and subjects with bipolar II or rapid cycling bipolar disorders. To assess affective instability, that study used two selfreport instruments, the Affect Intensity Measure and the Affective Lability Scale, and a new clinician-administered instrument, the Affective Interview for BPD (ALI-BPD) (Reich, Zanarini,
Copyright © 2013 John Wiley & Sons, Ltd.
& Fitzmaurice, 2012). The study found that borderline and bipolar subjects reported significant differences in affective instability with respect to both intensity and frequency. Notably, borderline subjects reported more frequent affective shifts between depression and anxiety, as well as between euthymia and anger. In addition, they reported more intense affective shifts between the following: depression and anxiety, euthymia and anger and euthymia and anxiety. This study used a self-report instrument, the Affective Lability Questionnaire (ALQ)-BPD, to examine possible differences in affective instability between subjects with elevated borderline traits and subjects with elevated bipolar traits. Items in this instrument differ from those in the ALI-BPD in several ways. First, the ALQ-BPD does not include mood shifts involving elation, which should be more characteristic of a bipolar disorder. Second, the ALQ-BPD contains several items not contained in the ALI-BPD. These items include shifts between anger and depression and shifts between anger and anxiety. In addition, the ALQBPD contains an item asking subjects to rate the extent to which affective changes are responsive to treatment by others. Methods Participants Subjects were 818 university undergraduates who participated for class credit and completed questionnaires online. The sample was 71.5% female undergraduates (N = 585), and ages ranged from 18 to 47 years (mean = 19.96, median = 20.0, standard deviation (SD) = 2.52). Most of the sample (83.1%) was Caucasian, whereas 4.9% was Asian American and 3.2% African American. Evaluation procedure and instruments Subjects were evaluated diagnostically using the Personality Assessment Inventory Mania Scale (PAI-MAN) (Morey, 1991), the PAI Borderline Scale (PAI-BOR) (Morey, 1991), the Zanarini
8: 143–150 (2014) DOI: 10.1002/pmh
Affective Instability in BPD and BD
Rating Scale for BPD: self-report version (ZANBPD) (Zanarini, 2003) and the ALQ-BPD. The PAI-MAN is a 24-item measure of manic symptoms with a 4-point Likert Scale. The PAI-BOR is a 24-item measure of symptoms of BPD symptoms with a 4-point Likert Scale. The ZAN-BPD contains nine items corresponding to the nine DSM-IV criteria for BPD. Subjects rate each item on a 5-point Likert Scale. The ALQ-BPD is a 10-item questionnaire, designed to measure affective instability over the last week. The first nine items of the instrument measure affective instability in nine dimensions: euthymia–depression, euthymia–anger, euthymia– anxiety, depression–anxiety, anxiety–depression, anger–depression, depression–anger, anger–anxiety and anxiety–anger. Each item has two components, the first asking subjects to rate the frequency of affective shifts, and the second asking subjects to rate the intensity of shifts for that dimension. The frequency component of each item asks subjects to rate the frequency of affective shifts for that dimension on a 5-point Likert scale: 0, not at all; 1, once per week; 2, 2–3 times per week; 3, once per day and 4, more than once per day. The intensity component of each item asks subjects to rate the intensity of shifts in that affective dimension on a 4-point scale: 1, slight; 2, moderate; 3, very large shift and 4, severe. The tenth item on the ALQ asks subjects to rate the extent to which their mood shifts were reactive to the way that someone treated them on a 5-point scale: 1, almost never (0–10% of the time); 2, sometimes (11–35% of the time); 3, about half the time (36–65% of the time); 4, most of the time (66–90% of the time) and 5, almost always (91–100% of the time). The scores on each of the frequency items for questions 1–9 can be added to produce an overall frequency scale; the scores on each of the intensity of items for questions 1–9 can be added to produce on overall intensity scale. We classified subjects as bipolar if their score on the PAI-MAN was two SDs or more above the mean PAI-MAN score for this sample. We classified subjects as borderline if their score on the PAI-BOR was two SDs or greater than the mean PAI-BOR
Copyright © 2013 John Wiley & Sons, Ltd.
score for this sample. To be included in the analysis, subjects could not be classified with both bipolar disorder and BPD. Statistical methods Between-group differences were assessed using Wilcoxon’s rank sum test for: (1) ALQ-BPD scales constructed to measure overall frequency and overall intensity of affective instability; (2) individual intensity items on the ALQ-BPD; (3) individual frequency items on the ALQ-BPD and (4) subject ratings of how frequently their moods changed in response to how others treated them. The Wilcoxon’s rank sum test is relatively insensitive to skewness or extremes in the distribution of these scales; however, for ease of interpretation, summary statistics for each group are presented in terms of means and SD. To correct for multiple comparisons, p-values for comparisons involving individual items were adjusted using Hochberg’s procedure. To assess convergent validity, we used Spearman’s rho to obtain correlations between the sum of items 1–9 on the ALQ and the score of the item measuring affective instability on the ZAN-BPD. To assess reliability/internal consistency we computed Chronbach’s alpha separately for frequency and intensity items. Results In the study, 732 subjects completed the PAI-BOR, and 739 subjects completed the PAI-MAN. There were no significant differences in age or gender for subjects completing the PAI-BOR and PAI-MAN compared with subjects who did not complete these assessments. Twenty-one (2.8%) subjects in the sample completing the PAI-MAN met study criteria for bipolar disorder, and 30 (4.1%) subjects completing the PAI-BPD met study criteria for BPD. We excluded two subjects because they met criteria for both bipolar disorder and BPD. The mean age of subjects in the bipolar group was 19.4 years, and the mean age in the borderline group was 19.3 years. This
8: 143–150 (2014) DOI: 10.1002/pmh
145
146
Reich et al.
difference was not statistically significant. Thirteen subjects (68.4%) in the bipolar group and 24 subjects (88.9%) in the borderline group were women. This difference was not statistically significant. The Crohnbach’s alpha for all subjects completing the ALQ-BPD was 0.90 for frequency items and 0.88 for intensity items. The convergent validity of the ALQ, as assessed by the correlation between total ALQ lability scores and scores on the ZAN-BPD: self-report version affective instability item, was 0.50 (p < 0.001). The mean score on the ALQ-BPD frequency scale for subjects not classified as having either elevated BPD or bipolar features was 7.0 (SD = 5.7), qualitatively similar to the mean in the bipolar group. The mean score on the ALQ-BPD intensity scale was 8.9 (SD = 6.0), discernibly lower than the mean for the BPD and bipolar groups. Table 1 displays scores for ALQ frequency items for the borderline and bipolar groups. As seen in this table, borderline subjects reported significantly more frequent mood shifts in seven of the nine affective dimensions: euthymia– depression, euthymia–anxiety, euthymia–anger, anxiety–depression, depression–anxiety, depression–anger and anger-depression. Bipolar subjects
did not report more frequent shifts in any of the nine affective dimensions. For both groups, the most frequently reported affective shifts were between euthymia and depression. The Total Frequency Scale score was significantly greater for the borderline group, over twice as large as the score for the bipolar group. Table 2 details scores for ALQ intensity items for the borderline and bipolar groups. Borderline subjects reported significantly more intense affective shifts in only two dimensions; euthymia– depression and anxiety–depression. There was a trend for borderline subjects to report more intense shifts from euthymia into anxiety than those reported by bipolar subjects. As with frequency items, bipolar subjects did not report more intense shifts in any of the nine dimensions. The mean Total Intensity Scale score was significantly larger for borderline subjects, almost twice as large as the score for bipolar subjects. The mean score on the ALQ question 10, asking how frequently subjects believed their affective shifts occurred in reaction to how others treated them, was significantly greater for borderline than bipolar subjects (2.5 vs. 1.5, Z = 3.28, p = .001).
Table 1: Comparison of Affective Lability Questionnaire frequency scores for BPD and bipolar groups BPD (N = 28) Mean Total Frequency Scale Euthymia–depression Euthymia–anxiety Euthymia–anger Depression–anxiety Anxiety–depression Depression–anger Anger–depression Anxiety–anger Anger–anxiety
18.8 3.2 2.5 2.2 2.2 2.1 1.6 2.0 1.5 1.5
Bipolar (N = 19) SE
Mean
SE
1.4 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
7.7 1.2 1.0 1.0 0.9 0.7 0.6 0.7 0.9 0.7
1.3 0.2 0.3 0.2 0.2 0.3 0.2 0.2 0.3 0.3
Z-Scorea 4.43 4.65 3.76 3.31 3.74 3.39 3.20 3.67 1.65 2.19
p-valueb
