Association of NEO personality domains and facets

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Longitudinal analysis of depression severity data after 3 and 12 months of psychiatric ... Key Words: Personality, depression, neuroticism, extraversion, conscientiousness ... and greater risk of developing new depression. 22 ...... .900. Activity (E4) -0.10 (-0.32 to 0.12) .930 -0.19 (-0.47 to 0.09) .517 -0.21 (-0.51 to 0.08) .388.
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Association of Five Factor Model personality domains and facets with presence, onset, and treatment outcomes of major depression in older adults

R. David Hayward, PhD1 Warren D. Taylor, MD, MHS2 Moria J. Smoski, PhD2 David C. Steffens, MD, MHS2,4 Martha E. Payne, PhD, RD, MPH1,3 School of Public Health, University of Michigan, Ann Arbor, MI, USA1 Department of Psychiatry and Behavioral Sciences2, Neuropsychiatric Imaging Research Laboratory3, and Department of Medicine4, Duke University Medical Center, Durham, NC, USA

The final and definitive version of this article is available at elsevier.com Hayward, R. D., Taylor, W. D., Smoski, M. J., Steffens, D. C., & Payne, M. E. (2013). Association of Five-Factor Model personality domains and facets with presence, onset, and treatment outcomes of major depression in older adults. American Journal of Geriatric Psychiatry, 21(1), 88-96. doi: 10.1016/j.jagp.2012.11.012

Corresponding author: R. David Hayward Department of Health Behavior and Health Education School of Public Health University of Michigan 1415 Washington Heights Ann Arbor, Michigan 48109-2029 Email: [email protected] This project was funded by National Institutes of Health grants MH54846, MH60451, and MH70027. No disclosures to report.

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Abstract Objectives: To assess the relationship of multiple domains and facets of the five factor model of personality with measures of late life depression including presence, age of onset, and severity at baseline and after 3 and 12 months of treatment. Design: Cross-sectional analysis of depression status, and age of onset. Retrospective analysis of baseline severity. Longitudinal analysis of depression severity data after 3 and 12 months of psychiatric treatment, using personality data collected after baseline. Setting: Private university-affiliated medical center in the Southeastern US. Participants: One hundred twelve psychiatric patients with a current episode of unipolar major depression, and 104 nondepressed comparison subjects, ages 60 years and older (mean = 70, SD = 6). Measurements: Revised NEO Personality Inventory, Diagnostic Interview Schedule, Montgomery-Åsberg Depression Rating Scale. Results: Binary logistic regression found that being depressed was related to higher neuroticism (and all its facets), and to lower extraversion (and facets of assertiveness, activity, and positive emotionality), and conscientiousness (and facets of competence, order, dutifulness, and selfdiscipline). Multinomial logistic regression found that some of these relationships held only for depression with onset before age 50 (hostility, self-consciousness, extraversion, assertiveness, positive emotions, order, and dutifulness). Linear regression found that personality was unrelated to depression severity at the beginning of treatment, but improvement after 3 months was related to lower neuroticism (and facets depressiveness and stress-vulnerability) and higher warmth and competence. Improvement after 12 months was related to lower neuroticism, depressiveness, and stress-vulnerability.

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Conclusions: Specific personality facets are related with depression and treatment outcomes. Key Words: Personality, depression, neuroticism, extraversion, conscientiousness

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The relationship of personality to depression has long been a subject of clinical interest1. Since personality traits tend to develop early in life and remain relatively stable2,3, identifying those traits associated with greater vulnerability to depression has significant clinical implications for screening patients in high risk groups and predicting responses to treatment4. The public health implications of early prediction are particularly important with respect to late life depression, which is a common and serious mental health problem5, associated with increased risk of disability6, hospitalization7, and mortality8. While several large studies have found links between personality and diagnoses of depression during younger adulthood9,10, few such studies have examined this relationship among older adults11. The role of specific personality traits (also known as “facets”) has also been relatively overlooked, as most studies have focused on broader aggregate domains of personality. The five-factor model (FFM) conceptualizes personality in terms of five broad domains – neuroticism (N), extraversion (E), openness (O), agreeableness (A), and conscientiousness (C) – each of which is composed of a related set of more specific traits or facets12. Ratings of individuals’ personality according to the FFM have been found to remain highly stable throughout adulthood2,13,14, including during and after periods of depression15,16. Therefore, understanding the relationship between these factors and mental health outcomes may hold the prospect of early screening for risk of depression later in life. A recent meta-analysis of studies covering mental health in all age groups found that incidence and severity of mood disorders, including depression, were strongly associated with high N, low E, and low C, and were also more weakly associated with low A17. In studies of geriatric depression, high N has been linked with more likely presence18, worse symptom severity19, and worse outcomes from treatment20,

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greater risk of recurrence21, and greater risk of developing new depression22. Findings have been less consistent across studies for other FFM domains. Presence of depression was related to low E, low E, and low C18; greater severity of symptoms was related to low E, low O, and low A19; worse treatment outcomes were related to low O and low A23; greater risk of developing new depression was related to low C22. The domains of the FFM, as measured by the gold-standard NEO-PI-R24, can be further divided into facets. Fewer studies have examined the association of specific personality facets in depression, but those studies have found some differences between facets within the same domains. For example, in a sample of university students, higher scores on the domain of O were associated with more symptoms of depression, but higher scores on the specific trait of openness to action (O4) were associated with fewer symptoms. In the same study, suicidal ideation was positively associated with the depressiveness (N3) facet of N, but negatively associated with selfconsciousness (N4)25. An epidemiological study found that, while the presence of depression in a community sample was associated with higher scores on all five of the facets of N, low scores on only one facet of conscientiousness, self-discipline (C5) were related26. In a study of geriatric depression patients, worse symptom severity was associated with stress vulnerability (N6), and competence (C1), but not with any other facets N or C20. This study uses a sample of depressed older adults and non-depressed comparison subjects to examine the relationship of all 35 domains and facets of the NEO PI-R12,24 with depression. This study improves upon previous research involving the FFM and late life depression due to the large size of the sample of psychiatric patients and the inclusion of a comparison group with no history of depression. Furthermore, this is only the second study of which we are aware to examine facets of the NEO PI-R, in addition to its domains, in relation to

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late life depression. In addition to presence of major depression, outcomes assessed include age of first depression onset, initial severity of current depression episode, and extent of improvement following treatment. The NEO PI-R was administered after treatment began, and is used as a retrospective measure in this study, as previous research has found this measure to be stable2,3,13,14, even during and after periods of depression15,16. Based on previous research, we hypothesized that higher N, especially stress vulnerability, is related to greater likelihood of depression, worse depression at baseline, and worse outcomes following treatment, while higher E and C are related to less likelihood of depression, less severe depression at baseline, and better outcomes after treatment. Few previous studies have addressed the particular FFM facets that contribute to these relationships, and we treat our analyses with these variables as exploratory in this study. METHOD Research Design Participants, aged 60 and older, were a subset of those enrolled in the Neurocognitive Outcomes of Depression in the Elderly (NCODE) study27 at Duke University Medical Center, a prospective cohort study of depressed patients and non-depressed comparison subjects. The present study includes a subset of those who agreed to participate in an auxiliary study of personality between February 1998 and February 2001. This sample included participants who were enrolled and received initial assessments in the NCODE study between December 1994 and June 2000. The present study uses data on depression severity at intake and after intervals of 3 and 12 months of treatment. Depending on when each participant entered the study and when they completed the NEO PI-R, depression data predates personality assessment by between 0 and

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62 months (mean = 19, SD = 15). Thus, personality is treated as a retrospective measure in this study, and is used in the analysis of depression severity data collected earlier. The depressed group was recruited from among inpatients and outpatients from the Duke Psychiatric Service meeting DSM-IV criteria for a current episode of Major Depressive Disorder (MDD). Exclusion criteria included concurrent diagnosis of other psychiatric or neurological illness, significant cognitive impairment, substance abuse, and contraindication to MRI. Depressed patients were assessed at intake and thereafter during the course of treatment at intervals of 3 months or less by a geriatric psychiatrist using the Montgomery-Åsberg Depression Rating Scale (MADRS)28, as described under “measures” below. Non-depressed comparison subjects were recruited from the Center for Aging Subject Registry at Duke University, which includes community-dwelling older adults living in central North Carolina who have volunteered to take part in research. Eligibility for the control group required a nonfocal neurological examination, no self-report of neurologic or depressive illness, and no evidence of any lifetime depression diagnosis based on the NIMH Diagnostic Interview Schedule29. All subjects provided informed consent before beginning any study procedures. The NCODE study was approved by the Duke University Health System Institutional Review Board. Measures Personality. Participants completed the Revised NEO Personality Inventory (NEO PIR)24, a self-administered 240-item assessment, which provides measures for each of the five factors and 30 facets constituting the five-factor model of personality12. The NEO PI-R produces percentile scores for each factor and facet on a scale from 0 – 100 that are normed within gender and age groups to the general US population.

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Depression severity. Depressed patients were assessed by clinicians using the Montgomery-Åsberg Depression Rating Scale (MADRS)28, an instrument designed to be sensitive to changes due to treatment, and which has high inter-rater reliability30. The MADRS provides a rating of depression severity on a scale from 0 – 60, with scores from 0 – 6 indicating remitted depression, 7 – 19 mild depression, 20 – 34 moderate depression, and 35 – 60 severe depression. Patients were assessed on intake to the study, and thereafter at intervals of approximately 3 months during the course of treatment. Demographics. Self-reported demographic characteristics used as covariates in this study included sex, age, race, and years of education (used as a proxy for socioeconomic status). Analysis Three types of analyses were conducted to examine the relationship of personality with depression. For each family of analyses, each NEO factor and facet was entered separately into a model including all applicable covariates. First, for all participants who completed the NEO PIR, binary logistic regression was applied on membership in the depressed versus comparison group. Second, depressed patients were further categorized by self-reported age of first episode of depression into early onset (age < 50) or late onset (age >= 50)31, and multinomial logistic regression was applied on the resulting three-category dependent variable (never depressed vs. early depression onset vs. late depression onset). Finally, for the depressed patients only, linear regression was used to assess the relationship of personality with depression severity at three points: intake, after 3 months of treatment, and after 12 months of treatment. Analyses on each of the two latter dependent variables included initial depression severity as a covariate. To correct for the large number of comparisons within each family of analyses, all critical alphas and p-values were adjusted using the Dubey/Armitage-Parmar method32, which is

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based on the Sidak method and includes a correction for correlation among key variables. All pvalues presented are adjusted based on a series of 35 comparisons including variables with a mean r = .26 derived from the observed correlation matrix in this sample of all NEO factors and facets. RESULTS A total of 216 participants, including 112 depressed patients and 104 non-depressed comparison subjects, completed the NEO PI-R and were included in the binary logistic regression analyses. Two participants in the depressed group had missing data for age of onset, and were excluded from the multinomial logistic regression analyses (N = 214). All participants in the depressed group were included in the linear regression analyses of depression severity (N = 112). Demographics for both groups are presented in Table 1. The comparison group was slightly older and more highly educated than the depressed group, but the composition of the two groups did not differ in terms of sex or race. Demographic factors (age, sex, race, and years of education) were controlled for in all subsequent analyses. Depression group status. Results of logistic regression analyses on depressed versus comparison group status are presented in Table 2. Greater N was significantly related to greater likelihood of being depressed at the domain level and on each of its facets, including anxiety (N1), hostility (N2), depressiveness (N3), self-consciousness (N4), impulsivity (N5), and stress vulnerability (N6). Greater E was significantly related to less likelihood of depression as a domain, as well as on the facets of assertiveness (E3), activity (E4), and positive emotions (E6). Greater C was significantly related as a domain to reduced likelihood of being depressed, and on the facets of competence (C1), order (C2), dutifulness (C3), and self-discipline (C5). Neither O, A nor any of their facets was significantly related to depression status.

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Age of depression onset. Multinomial logistic regression results are presented in Table 3. Seven of the personality-depression relationships described above were found to hold only for those with earlier ages of onset (N2, N4, E, E3, E6, C2, and C3), while nine had similar associations with depression regardless of age of onset (N, N1, N3, N5, N6, E4, C, C1, and C5). In addition, a significant relationship was detected between depression with early onset and the A facet of trust (A1). No personality factors or facets were significantly related to early versus late onset among the depressed. Depression severity. Results of linear regression analyses on MADRS depression severity scores among the depressed group at baseline and at 3 and 12 month follow up are presented in Table 4. No significant relationships were detected between dimensions of personality and MADRS at baseline. Personality was related to MADRS after treatment (controlling for baseline depression severity) on certain facets of N, C, and E, but was unrelated to either O, A or any of their facets. Greater depression severity after 3 months of treatment was significantly associated with higher N, as well as with the facets of depressiveness (N3), and stress-vulnerability (N6). Lower depression severity after 3 months was also significantly associated with warmth (E1) and competence (C1). After 12 months of treatment, this pattern was the same for N and its facets; greater depression severity remained significantly associated with higher N, and with the facets of depressiveness (N3) and stress-vulnerability (N6). However, after 12 months of treatment there were no longer any significant associations between depression severity and either E, C, or any of their facets.

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DISCUSSION This study found that multiple dimensions of personality were associated both with the incidence of depression in older adults, as well as with severity of depressive symptoms following treatment. Furthermore, analyses of specific personality traits showed differences in these relationships between different facets within the same broad personality domains. Consistent with our hypotheses, the personality domain neuroticism (N) was associated with the presence of depression (both early and late onset) and with outcomes after treatment among the depressed. N scores were higher among the depressed patients than the comparison subjects, and higher N was associated with more severe depression remaining after 3 and 12 months of treatment (although it was unrelated to severity of depression at baseline). Findings were more complicated with respect to the domains of extraversion (E) and conscientiousness (C). While both domains were related to the presence of depression, only particular facets within these domains were associated with outcomes after treatment. The present findings regarding domain-level personality and depression status recapitulate previously published findings that also used data from the NCODE study18,33 in showing depressed versus comparison status to be related to higher neuroticism, lower extraversion, and lower conscientiousness*. At the personality domain level, a contrast emerged between N (which was related depression status on all of its facets) and E and C (which showed relationships only on some facets). In particular, lower scores on assertiveness (E3), activity (E4), and positive emotions (E6) were related to depression, while scores on the facets of warmth (E1), gregariousness (E2), and excitement seeking (E5) were not. Similarly, competence (C1), order (C2), dutifulness (C3), and self-discipline (C5) were related to depression, while

*

Both of these publications reported a relationship between openness and depression status which was not detected in the present analyses because of the inclusion of years of education as a covariate.

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achievement-striving (C4) and deliberation (C6) were not. Our findings add another point of confirmation that neuroticism remains an important factor in depression in to late life. It is especially striking that N and several of its facets are predictive of depression regardless of age of onset. More broadly, these facet-level results may help to put previous studies’ findings at the domain level into perspective. While N has been strongly and consistently been found to be positively related to depression4,17, the negative associations of E and C with depression detected in meta-analyses17 have not always been found in individual studies19,21,22. If only a subset of the facets of E and C are related to depression, this could help to explain why results using the full combined factors are sometimes weak or inconsistent. Contrary to expectations, personality was unrelated to baseline depression severity – which was measured during an episode of major depression – but was related on several dimensions to post-treatment depression severity. This pattern suggests that while personality may not play a significant role in the severity of the acute experience of depression, it may however affect patients’ overall risk for disorder, as well as response to treatment. N and its facets of depressiveness (N3) and stress vulnerability (N6) appear to play the biggest role, each predicting worse outcomes. By contrast, less severe depression following treatment was related to the facets of warmth (E1) and competence (C1), although not to the corresponding domains of E and C. Furthermore, while the negative impact of N remained after 12 months of treatment, the effects of warmth (E1) and competence (C1) were present at 3 months only. One possible explanation for this discrepancy may be that the latter traits have an influence in ways that can be compensated over the course of treatment, while elements of neuroticism reflect an enduring psychological source of risk for depression. For example, low warmth may inhibit the initial formation of a positive relationship with mental health care providers, and the lack of perceived

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self-efficacy associated with low competence may make patients slower to comply fully with treatment, in each case slowing the rate of recovery from depression, but not decreasing the final extent of that recovery. These results partially support the findings of one smaller previous study which examined improvement in depression severity after 3 months of treatment20, in that neuroticism and stress vulnerability were related to worse outcomes, while competence was related to better outcomes. That study, however, found no effects for depressiveness or warmth. Another small study, which did not measure depression severity, found that facets of openness and agreeableness were related to more positive termination of group psychotherapy after 3 months23. While these results suggest that specific personality facets may be more useful than broader factors in predicting treatment outcomes, they do not yet present a clear pattern, and more research is needed to better articulate these relationships. These results may also have certain clinical implications, both for the use of personality tests in screening for risk and for targeting treatment at particular potentially problematic cognitive styles. For example, several factors related to planning, executing, and gaining enjoyment from activities were low in depressed participants (specifically assertiveness (E3), activity (E4), positive emotions (E6), competence (C1), order (C2), dutifulness (C3), and selfdiscipline (C5)) and were predictive of treatment outcome at 3 months (competence) which may speak to the benefit of additional support via behavioral activation or problem-solving therapies for patients with these personality traits. The facet-based approach to personality measurement also helps to address some potential concerns regarding the conceptual overlap between the domain of neuroticism (N) and outcomes related to mental health. In particular, N includes the facet of depressiveness (N3), conceived as the extent to which one generally experiences sad or depressed moods. While it is

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possible to score highly on this personality trait without having a clinically diagnosable disorder, N3 is also directly conceptually related to some of the key symptoms of depression. Thus, the correlation between N and depression is likely to be inflated due to the way in which N3 is defined and measured. Examining the impact of particular facets in this study showed that, while N3 has a strong relationship with depression, it is not the only facet of N that does so. All facets of N were related to depression status, while stress-vulnerability (N6) was related to follow-up severity, along with N3 and the combined N domain. This pattern of results, showing effects for facets of N even when N3 is excluded, provide some support for the validity of findings regarding neuroticism and depression by suggesting that they are not explained as an artifact of measurement. LIMITATIONS Limitations of this study include the timing of administration of the NEO PI-R in relation to measurement of depression severity, and differences in recruitment procedures between the depressed and comparison samples. The fact that personality was measured up to several years after the baseline and post-treatment depression severity measurements may limit interpretation of the longitudinal results, if personality changed in the interim, either as the result of treatment, or as part of the aging process. This concern is at least partially mitigated by previous studies which have found that personality in general, and measurement on the NEO PI-R in particular, remain highly stable within individuals across the life span2,13, including in later adulthood14 and among patients with major depressive disorder15,16. Nevertheless, future research should seek to measure personality prior to depression onset. With respect to group differences in recruitment, while efforts were made to recruit a comparison group matching the depressed group as closely as possible, there are inevitable differences between psychiatric patients and community

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volunteers. Depression status analyses controlled for demographic factors that were known to differ between groups, but some personality differences between groups may still be attributable to differences in the types of people willing to volunteer under these two sets of conditions. However, the fact that we found no differences in agreeableness or its facets (which would seem to be the most likely characteristics to distinguish those with unusually volunteering dispositions) may suggest that this methodological effect is not very severe. CONCLUSIONS This study found relationships between multiple dimensions of personality and the presence of depression, its age of onset, and its severity after 3 and 12 months of treatment in a sample of older adults. The measurement of specific personality facets, in addition to more general personality domains, revealed differences in effects among facets within the same domain. Furthermore, different specific elements of personality were found to be associated with different outcomes related to incidence, onset, and severity. These results support the existence of enduring effects of personality on depression in late life, and help to identify particular sets of characteristics that may place individuals at increased risk of depression, or that may make them less susceptible to successful treatment.

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TABLE 1. Demographics p Valuea

Total

Depressed

Comparison

(N =216)

(N = 112)

(N = 104)

Age (years)b

70.41 (5.94)

69.45 (6.08)

71.45 (5.62)

.013

Female

142 (65.7%)

69 (61.6%)

73 (70.2%)

.184

White

189 (87.5%)

101 (90.2%)

88 (84.6%)

.217

Education (years) b

14.56 (2.43)

13.92 (2.64)

15.26 (1.96)

< .001

a

p value for difference between groups (χ2 test with df = 1 used to compare proportions; t-test

with df = 214 used to compare means). b

Mean (standard deviation).

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TABLE 2. Binary logistic regression results for personality factors and facets on depression status Depression Statusa OR

95% CIb

pb

1.14

(1.07 to 1.21)

< .001

Anxiety (N1)

1.11

(1.06 to 1.17)

< .001

Hostility (N2)

1.07

(1.02 to 1.13)

< .001

Depressiveness (N3)

1.16

(1.08 to 1.23)

< .001

Self-Consciousness (N4)

1.06

(1.01 to 1.10)

.007

Impulsivity (N5)

1.11

(1.05 to 1.17)

< .001

Stress-Vulnerability (N6)

1.12

(1.06 to 1.18)

< .001

0.95

(0.90 to 0.99)

.002

Warmth (E1)

0.96

(0.91 to 1.00)

.068

Gregariousness (E2)

1.00

(0.96 to 1.04)

.999

Assertiveness (E3)

0.95

(0.91 to 0.99)

.048

Activity (E4)

0.93

(0.88 to 0.98)

< .001

Excitement-Seeking (E5)

1.03

(0.97 to 1.08)

.937

Positive Emotions (E6)

0.95

(0.91 to 0.99)

.003

0.98

(0.94 to 1.03)

.972

Fantasy (O1)

1.00

(0.95 to 1.06)

.999

Aesthetics (O2)

0.99

(0.95 to 1.03)

.999

Feelings (O3)

1.00

(0.96 to 1.04)

.999

Actions (O4)

0.98

(0.94 to 1.02)

.926

Ideas (O5)

0.97

(0.92 to 1.02)

.497

Values (O6)

0.99

(0.95 to 1.04)

.999

0.98

(0.93 to 1.03)

.958

Neuroticism (N)

Extraversion (E)

Openness (O)

Agreeableness (A)

22 Trust (A1)

0.95

(0.90 to 1.00)

.105

Straightforwardness (A2)

0.99

(0.95 to 1.04)

.999

Altruism (A3)

0.99

(0.95 to 1.02)

.995

Compliance (A4)

0.97

(0.92 to 1.01)

.341

Modesty (A5)

1.02

(0.98 to 1.07)

.815

Tender-Mindedness (A6)

1.01

(0.96 to 1.05)

.999

0.93

(0.89 to 0.98)

< .001

Competence (C1)

0.94

(0.90 to 0.98)

< .001

Order (C2)

0.94

(0.90 to 0.98)

< .001

Dutifulness (C3)

0.94

(0.89 to 0.99)

.005

Achievement-Striving (C4)

0.97

(0.93 to 1.01)

.421

Self-Discipline (C5)

0.93

(0.88 to 0.97)

< .001

Deliberation (C6)

0.96

(0.92 to 1.01)

.157

Conscientiousness (C)

NOTE: All coefficients based on separate logistic regression models a

Adjusted for sex, age, race, and years of education

P-values for Wald χ2 with df = 1, adjusted for multiple comparisons using the Dubey/Armitage-Parmar method b

23

TABLE 3. Multinomial logistic regression results for personality factors and facets on age of depression onset Early Onset vs. Non-Depressed a OR

95% CIb

Late Onset vs. Non-Depresseda

Pb

OR

95% CIb

Pb

Late Onset vs. Early Onseta OR

95% CIb

Pb

1.16

(1.08 to 1.24)

< .001

1.10

(1.03 to 1.18)

< .001

0.96

(0.90 to 1.01)

.226

Anxiety (N1)

1.14

(1.07 to 1.21)

< .001

1.08

(1.01 to 1.15)

.009

0.95

(0.89 to 1.00)

.089

Hostility (N2)

1.09

(1.03 to 1.16)

< .001

1.05

(0.98 to 1.12)

.471

0.96

(0.90 to 1.02)

.554

Depressiveness (N3)

1.18

(1.09 to 1.26)

< .001

1.13

(1.05 to 1.21)

< .001

0.96

(0.91 to 1.02)

.431

Self-Consciousness (N4)

1.07

(1.02 to 1.13)

< .001

1.03

(0.97 to 1.09)

.978

0.95

(0.90 to 1.01)

.281

Impulsivity (N5)

1.12

(1.05 to 1.19)

< .001

1.08

(1.01 to 1.16)

.007

0.97

(0.91 to 1.03)

.894

Stress-Vulnerability (N6)

1.12

(1.06 to 1.19)

< .001

1.11

(1.04 to 1.18)

< .001

0.98

(0.94 to 1.03)

.993

0.94

(0.89 to 0.99)

.021

0.96

(0.90 to 1.02)

.637

1.02

(0.96 to 1.09)

.998

Warmth (E1)

0.95

(0.90 to 1.00)

.052

0.96

(0.91 to 1.02)

.716

1.02

(0.96 to 1.08)

.999

Gregariousness (E2)

0.99

(0.95 to 1.04)

.999

1.01

(0.95 to 1.07

.999

1.01

(0.96 to 1.06)

.344

Assertiveness (E3)

0.95

(0.90 to 0.99)

.045

0.96

(0.91 to 1.03)

.683

1.02

(0.96 to 1.08)

.999

Activity (E4)

0.94

(0.88 to 0.99)

.009

0.92

(0.85 to 0.98)

.005

0.98

(0.92 to 1.05)

.999

Excitement-Seeking (E5)

1.03

(0.97 to 1.09)

.867

1.02

(0.95 to 1.09)

.999

0.99

(0.92 to 1.06)

.999

Positive Emotions (E6)

0.93

(0.89 to 0.98)

< .001

0.98

(0.93 to 1.03)

.949

1.05

(0.99 to 1.11)

.213

1.00

(0.95 to 1.05)

.999

0.99

(0.94 to 1.04)

.999

0.95

(0.89 to 1.01)

.261

Neuroticism (N)

Extraversion (E)

Openness (O)

24

Fantasy (O1)

1.03

(0.97 to 1.09)

.943

0.97

(0.90 to 1.03)

.876

0.94

(0.87 to 1.01)

.186

Aesthetics (O2)

1.00

(0.95 to 1.05)

.999

0.97

(0.91 to 1.03)

.765

0.96

(0.90 to 1.03)

.746

Feelings (O3)

1.01

(0.96 to 1.07)

.999

0.97

(0.92 to 1.03)

.937

0.96

(0.90 to 1.02)

.552

Actions (O4)

0.98

(0.93 to 1.03)

.994

0.97

(0.92 to 1.04)

.960

0.99

(0.93 to 1.06)

.999

Ideas (O5)

0.98

(0.93 to 1.03)

.940

0.95

(0.89 to 1.01)

.279

0.98

(0.92 to 1.04)

.977

Values (O6)

1.00

(0.96 to 1.05)

.999

0.97

(0.92 to 1.03)

.947

0.97

(0.91 to 1.03)

.907

0.99

(0.94 to 1.04)

.999

0.97

(0.91 to 1.03)

.891

0.98

(0.92 to 1.05)

.999

Trust (A1)

0.94

(0.88 to 0.99)

.031

0.98

(0.91 to 1.06)

.999

1.05

(0.97 to 1.13)

.689

Straightforwardness (A2)

1.00

(0.95 to 1.06)

.999

0.97

(0.91 to 1.04)

.962

0.97

(0.91 to 1.04)

.959

Altruism (A3)

0.99

(0.95 to 1.03)

.997

0.99

(0.95 to 1.04)

.999

1.00

(0.96 to 1.05)

.999

Compliance (A4)

0.97

(0.92 to 1.02)

.663

0.96

(0.90 to 1.02)

.417

0.99

(0.93 to 1.05)

.999

Modesty (A5)

1.03

(0.98 to 1.09)

.529

1.01

(0.95 to 1.07)

.999

0.97

(0.92 to 1.03)

.946

Tender-Mindedness (A6)

1.02

(0.97 to 1.07)

.992

0.98

(0.92 to 1.04)

.997

0.96

(0.90 to 1.03)

.699

0.93

(0.88 to 0.98)

< .001

0.94

(0.88 to 0.99)

.013

1.01

(0.96 to 1.07)

.999

Competence (C1)

0.94

(0.89 to 0.98)

.001

0.94

(0.89 to 0.99)

.008

1.00

(0.96 to 1.05)

.999

Order (C2)

0.94

(0.89 to 0.98)

.001

0.95

(0.89 to 1.00)

.061

1.01

(0.96 to 1.07)

.999

Dutifulness (C3)

0.93

(0.87 to 0.98)

.001

0.96

(0.90 to 1.03)

.765

1.04

(0.97 to 1.11)

.707

Achievement-Striving (C4)

0.98

(0.94 to 1.02)

.870

0.96

(0.91 to 1.01)

.278

0.98

(0.93 to 1.03)

.994

Agreeableness (A)

Conscientiousness (C)

25

Self-Discipline (C5)

0.92

(0.87 to 0.97)

< .001

0.94

(0.89 to 0.99)

.019

1.02

(0.97 to 1.07)

.986

Deliberation (C6)

0.96

(0.92 to 1.01)

.147

0.97

(0.92 to 1.02)

.744

1.01

(0.96 to 1.07)

.999

NOTES: Each row represents a separate multinomial regression model; Early onset < age 50, Late onset >= age 50 a

Adjusted for sex, age, race, and years of education

b

P-values for Wald χ2 with df = 1, adjusted for multiple comparisons using the Dubey/Armitage-Parmar method

26

TABLE 4. Linear regression coefficients for personality factors and facets on depression severity at baseline and after treatment Baseline Severitya pc

B

95% CIc

-0.04 (-0.20 to 0.13)

.999

0.24

Anxiety (N1)

0.02 (-0.15 to 0.20)

.999

Hostility (N2)

-0.11 (-0.31 to 0.08)

Depressiveness (N3)

12-month Severitya,b pc

B

(0.05 to 0.43)

.006

0.23 (0.02 to 0.44)

.025

0.22

(0.01 to 0.43)

.052

0.21 (-0.02 to 0.44)

.098

.739

0.18

(-0.07 to 0.43)

.439

0.18 (-0.08 to 0.45)

.480

-0.02 (-0.19 to 0.14)

.999

0.32

(0.13 to 0.51)

< .001

Self-Consciousness (N4)

0.01 (-0.16 to 0.17)

.999

0.14

(-0.07 to 0.34)

.513

0.06 (-0.16 to 0.28)

.999

Impulsivity (N5)

-0.08 (-0.28 to 0.11)

.965

0.05

(-0.20 to 0.31)

.999

0.11 (-0.16 to 0.38)

.973

Stress-Vulnerability (N6)

-0.03 (-0.16 to 0.10)

.999

0.20

(0.04 to 0.35)

.007

0.19 (0.01 to 0.36)

.027

-0.11 (-0.31 to 0.09)

.820

-0.23

(-0.49 to 0.02)

.108

-0.22 (-0.49 to 0.05)

.237

Warmth (E1)

-0.03 (-0.21 to 0.16)

.999

-0.29

(-0.51 to -0.07)

.002

-0.21 (-0.45 to 0.03)

.163

Gregariousness (E2)

-0.13 (-0.30 to 0.04)

.357

-0.04

(-0.27 to 0.19)

.999

-0.10 (-0.34 to 0.14)

.976

Assertiveness (E3)

0.01 (-0.20 to 0.23)

.999

-0.12

(-0.39 to 0.15)

.952

-0.14 (-0.43 to 0.15)

.900

Activity (E4)

-0.10 (-0.32 to 0.12)

.930

-0.19

(-0.47 to 0.09)

.517

-0.21 (-0.51 to 0.08)

.388

Excitement-Seeking (E5)

-0.18 (-0.41 to 0.05)

.296

0.03

(-0.28 to 0.34)

.999

-0.07 (-0.39 to 0.26)

.999

B Neuroticism (N)

Extraversion (E)

95% CIc

3-month Severitya,b

95% CIc

0.31 (0.11 to 0.51)

pc

< .001

27

Positive Emotions (E6)

-0.01 (-0.16 to 0.15)

.999

-0.19

(-0.38 to .01)

.058

-0.09 (-0.30 to 0.12)

.967

-0.03 (-0.22 to 0.16)

.999

-0.09

(-0.33 to 0.15)

.987

-0.01 (-0.27 to 0.24)

.999

Fantasy (O1)

-0.07 (-0.28 to 0.14)

.997

0.06

(-0.21 to 0.33)

.999

0.07 (-0.22 to 0.35)

.999

Aesthetics (O2)

-0.01 (-0.21 to 0.20)

.999

-0.11

(-0.36 to 0.15)

.971

0.06 (-0.22 to 0.33)

.999

Feelings (O3)

0.02 (-0.17 to 0.22)

.999

-0.04

(-0.28 to 0.21)

.999

0.03 (-0.24 to 0.29)

.999

Actions (O4)

-0.03 (-0.22 to 0.16)

.999

-0.12

(-0.36 to 0.12)

.881

-0.08 (-0.34 to 0.18)

.997

Ideas (O5)

-0.03 (-0.23 to 0.16)

.999

-0.13

(-0.37 to 0.12)

.854

-0.08 (-0.34 to 0.18)

.999

Values (O6)

0.01 (-0.20 to 0.20)

.999

-0.05

(-0.30 to 0.20)

.999

-0.04 (-0.21 to 0.23)

.999

0.02 (-0.19 to 0.23)

.999

0.03

(-0.24 to 0.29)

.999

0.01 (-0.27 to 0.29)

.999

0.03 (-0.17 to 0.22

.999

-0.08

(-0.32 to 0.17)

.998

-0.07 (-0.33 to 0.20)

.999

Straightforwardness (A2)

-0.06 (-0.29 to 0.17)

.999

0.17

(-0.13 to 0.46)

.753

0.05 (-0.27 to 0.36)

.999

Altruism (A3)

0.05 (-0.09 to 0.18)

.995

-0.06

(-0.24 to 0.11)

.993

-0.10 (-0.29 to 0.08)

.767

Compliance (A4)

0.03 (-0.18 to 0.24)

.999

-0.03

(-0.29 to 0.24)

.999

0.06 (-0.22 to 0.35)

.999

Modesty (A5)

0.05 (-0.16 to 0.25)

.999

0.15

(-0.10 to 0.41)

.697

0.17 (-0.11 to 0.44)

.666

Tender-Mindedness (A6)

-0.05 (-0.23 to 0.14)

.999

0.03

(-0.21 to 0.26)

.999

0.04 (-0.21 to 0.29)

.999

0.08 (-0.08 to 0.25)

.882

-0.17

(-0.37 to 0.04)

.248

-0.15 (-0.37 to 0.07)

.526

Competence (C1)

0.03 (-0.13 to 0.18)

.999

-0.19

(-0.38 to -0.01)

.048

-0.16 (-0.37 to 0.04)

.248

Order (C2)

0.11 (-0.07 to 0.28)

.652

-0.18

(-0.40 to 0.04)

.187

-0.15 (-0.38 to 0.09)

.617

Openness (O)

Agreeableness (A) Trust (A1)

Conscientiousness (C)

28

Dutifulness (C3)

0.03 (-0.17 to 0.23)

.999

-0.05

(-0.30 to 0.21)

.999

-0.12 (-0.39 to 0.15)

.942

Achievement-Striving (C4)

0.03 (-0.13 to 0.19)

.999

-0.16

(-0.35 to 0.04)

.229

-0.12 (-0.33 to 0.08)

.689

Self-Discipline (C5)

0.08 (-0.08 to 0.24)

.899

-0.08

(-0.29 to 0.13)

.983

-0.07 (-0.29 to 0.15)

.998

Deliberation (C6)

0.10 (-0.07 to 0.27)

.734

-0.07

(-0.28 to 0.15)

.999

-0.05 (-0.29 to 0.18)

.999

NOTE: All coefficients based on separate linear regression models a

Adjusted for sex, age, race, and years of education

b

Additionally adjusted for baseline depression severity

c

P-values for t-test with df = 107 (baseline severity) or df = 106 (3-month and 12-month severity), adjusted for multiple comparisons using the Dubey/Armitage-Parmar method

29