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Personality–life event congruence effects in late-life depression
Journal of Affective Disorders 84 (2005) 25 – 31 www.elsevier.com/locate/jad
Research report
Personality–life event congruence effects in late-life depression Jennifer Q. Morsea,*, Clive J. Robinsa,b a
Department of Psychology, Social and Health Sciences, Duke University, United States b Department of Psychiatry and Behavioral Sciences, Duke University, United States Received 10 February 2004; accepted 14 September 2004
Abstract Background: This study examined whether specific interactions of personality and life events predicted increases in depressive symptoms over time in a late-life sample. Method: Participants (n=55) who were in remission from a recent episode of major depression completed a depression symptom interview and a questionnaire assessing the personality constructs sociotropy and autonomy. Six months later, they completed the same personality questionnaire and a checklist of life events experienced during the past 6 months. Results: As predicted, increases in depressive symptoms were significantly predicted by the congruent interaction of sociotropy with negative interpersonal events and by the congruent interaction of autonomy with negative autonomy events, but not by either of the non-congruent interactions. Limitations: A small sample prevented examinations of important depressive subtypes based on age of depression onset and vascular status. Conclusions: These findings strongly support the personality–life event congruence model of depression in a late-life sample. Clinical implications include attending to stressful events that match an older adult’s personality style, to help the older adult cope with those events that are more likely to increase his or her depression. D 2004 Elsevier B.V. All rights reserved. Keywords: Late-life depression; Personality; Life events
Cognitive and psychoanalytic theories have converged on a similar theoretical framework describing personality characteristics that create vulnerability to depression following negative life events that are * Corresponding author. Now at Personality Studies, Western Psychiatric Institute and Clinic, 3811 O’Hara Street, Pittsburgh, PA 15213, United States. Tel.: +1 412 246 5838; fax: +1 412 246 5840. E-mail address: [email protected] (J.Q. Morse). 0165-0327/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jad.2004.09.007
congruent with those characteristics. Empirical studies of adult samples have supported this congruence hypothesis. While research on late-life depression has addressed its association with life events and personality, only one study has examined the role of interactions between personality characteristics and life events. Depression in late-life can have unique features, such as involvement of vascular disease, so the results with adult samples cannot necessarily be
26
J.Q. Morse, C.J. Robins / Journal of Affective Disorders 84 (2005) 25–31
generalized to late-life depression. This paper reports the results of an empirical test of the personality–life event congruence effect in a late-life sample. Theorists have suggested that normal personality development requires both interpersonal connection and self-definition (Arieti and Bemporad, 1980; Beck, 1983; Blatt, 1974; Bowlby, 1977) and that overemphasis on either theme creates vulnerability to depression, particularly following matching stressful life events. Highly sociotropic (Beck, 1983) or dependent (Blatt, 1974) people value close relationships, which may leave them vulnerable to depression after negative interpersonal events. Autonomous (Beck, 1983) or self-critical (Blatt, 1974) people value independence, mastery and control, which may leave them vulnerable to depression after perceived loss of control or failure. The interaction between sociotropy or autonomy and matching events predicts depressive relapse in adults (Hammen et al., 1989; Segal et al., 1992). Research on late-life depression has focused on main effects of life events or personality factors. There is a positive relation between depressive symptoms in older adults and negative life events (Kraaij et al., 1998). Clinically depressed patients reported both more frequent and more severe life events than did control groups (Emmerson et al., 1989). In terms of personality, neuroticism has received the most attention in late life. Neuroticism is related to greater depressive symptoms (Abrams et al., 1991) and predicts increased risk of developing late-life depression (Oldehinkel et al., 2001). Sociotropy and autonomy both correlate significantly with depressive symptoms in older adults (Allen et al., 1997). Thus, there is evidence linking both life events and personality to late-life depression, but the magnitude of these effects was modest and it is possible that interactions between personality and life events account for additional variance in depression in older adults. In the lone study investigating the interaction between personality and life events in late-life depression, Mazure et al. (2002) compared 42 late-onset depressed outpatients with 42 non-depressed elderly matched controls. Depressed group membership was associated both with the interaction between sociotropy and negative events and with the interaction between autonomy and negative events, which was interpreted as support for the congruence hypothesis. However, the event measure was nonspecific, rather than differ-
entiated into interpersonal and autonomy events, so it does not test the congruence hypothesis. And the study’s cross-sectional case-control design makes it impossible to infer causal directionality. The current study, in contrast, is prospective, testing the ability of the congruence hypothesis to predict the return of symptoms in a sample of patients who were in remission from a major depressive episode. In this study, we assessed sociotropy, autonomy, and depressive symptoms in a group of older adult patients who were in remission from a recent episode of major depressive disorder and reassessed depressive symptoms and recent life events 6 months later. Our primary hypothesis was that congruent interactions between the two personality variables and types of events would be associated with increases in depressive symptoms over the 6-month period.
1. Method 1.1. Participants Participants were recruited from a longitudinal study at the NIMH Clinical Research Center (CRC) for the Study of Depression in Late Life at Duke University. For inclusion in the CRC study, subjects met criteria for major depressive episode using the Duke Depression Evaluation Schedule for the Elderly (George et al., 1989) and had a Mini-Mental Status Exam (Folstein et al., 1975) score z25. For inclusion in the current study, participants had to be in remission, defined as Montgomery 2sberg Depression Rating Scale (Montgomery ˚ sberg, 1979) score V10. Patients with recent and A MMSE b25, a diagnosis of Alzheimer’s disease, or receiving electroconvulsive therapy were excluded. Seventy-two patients who met these criteria completed the initial assessment; 15 (21%) did not complete the second assessment and 2 (3%) had invalid data, based on visual inspection of the questionnaires following regression diagnostics. The demographics of the final sample are described in Table 1.1 1
Participants who completed the second survey (n=55) did not differ from those who did not (n=15) except for having lower MMSE error scores than non-completers (completers: M=1.06, S.D.=1.33, non-completers: M=1.88, S.D.=1.80, t(67)= 2.02, p=0.05) at CRC entry.
J.Q. Morse, C.J. Robins / Journal of Affective Disorders 84 (2005) 25–31
27
Table 1 Sample demographics and comparing depressive subgroups Overall (n=55)
Late onset (n=23)
Early onset (n=32)
v 2 (df)
Non-vascular (n=16)a
Vascular (n=33)
v 2 (df)
%Women %Married %Minority
64 64 7
69 66 3
57 61 13
0.87 (1) 0.13 (1) 1.95 (1)
63 69 13
64 58 6
0.01 (1) 0.57 (1) 0.60 (1)
t (df)
Mean (S.D.)
Mean (S.D.)
t (df)
Age Years of education Age of onset # previous episodes MMSE errors Deep white matter hyperintensities Subcortical hyperintensities Time 1 MADRS Time 2 MADRS Time 1 sociotropy Time 1 autonomy Time 2 sociotropy Time 2 autonomy Negative interpersonal events Negative autonomy events
68.09 14.37 46.70 4.27 1.06 1.53
Mean (S.D.)
1.31 (1.08) 2.60 5.07 86.00 77.63 86.63 78.95 1.93
Mean (S.D.)
(6.82) 67.96 (7.05) (2.27) 14.23 (2.29) (18.76) 65.77 (7.87) (5.04) 2.00 (1.55) (1.33) 1.18 (1.40) (1.01) 1.71 (1.19)
(3.20) (5.30) (14.09) (13.71) (15.98) (13.89) (2.01)
1.78 (1.54)
1.62 (1.12) 2.70 4.26 85.78 78.19 84.96 80.13 1.96
(3.65) (5.24) (15.21) (13.88) (14.66) (12.67) (2.34)
1.52 (1.47)
Mean (S.D.) 68.19 14.47 33.59 5.96 0.97 1.39
(6.76) (2.29) (11.15) (6.03) (1.30) (1.03)
1.07 (1.02) 2.53 5.66 86.15 77.23 87.84 78.07 1.91
(2.90) (5.35) (13.48) (13.79) (16.99) (14.87) (1.77)
1.97 (1.58)
0.12 (53) 66.50 (5.66) 68.39 (7.43) 0.38 (52) 14.38 (1.86) 14.52 (2.36) 11.67 (52)**** 44.81 (19.24) 47.85 (19.74) 4.11b **** 5.13 (7.81) 3.93 (3.50) 0.57 (50) 1.13 (1.64) 1.09 (1.28) 1.01 (47) 0.63 (0.50) 1.97 (1.05) 1.79 (47) 0.19 0.96 0.10 0.26 0.66 0.54 0.09
(53) (53) (53) (53) (53) (52) (53)
1.07 (53)
0.19 (0.40) 2.25 3.81 84.67 79.69 85.22 79.19 2.13
(2.70) (4.25) (14.65) (10.29) (18.35) (8.56) (2.03)
1.69 (1.62)
1.85 (0.87) 2.88 5.42 87.25 77.60 87.04 79.43 2.00
(3.34) (5.61) (14.42) (14.99) (16.18) (16.57) (2.11)
1.97 (1.49)
0.99 (38.11) 0.21 (47) 0.51 (47) 0.82b 0.09 (45) 6.09 (47)**** 9.13 (46.97)**** 0.66 1.01 0.58 0.50 0.35 0.05 0.20
(47) (47) (47) (47) (47) (46) (47)
0.60 (47)
a
MRI data were missing for six participants. Mann–Whitney U reported. **** pb0.0001.
b
1.2. Procedure At each appointment, a psychiatrist assessed depressive symptoms by interview. Subjects who were in remission were mailed the Personal Style Inventory (PSI, Robins et al., 1994) and received $3 for completing it. After a psychiatrist appointment 6 months later, participants completed the PSI and the Modified Schedule of Life Events (Bieliauskas et al., 1995) and received $15. Demographic and clinical information came from baseline CRC assessments. 1.3. Measures 1.3.1. Personal style inventory (Robins et al., 1994) This 48-item self-report measure assesses the key concerns of sociotropy and autonomy. Both scales have good internal consistency in depressed sam-
ples—sociotropy: a=0.83, autonomy: a=0.79 (Lynch et al., 2001), but the psychometric properties of the PSI among older adults are not known. 1.3.2. Schedule of life events—modified (Bieliauskas et al., 1995) This inventory of 48 negative and 6 positive life events was constructed for use with older adults. It has been modified for the present study. Details regarding the modification are available from the first author. The modified measure includes 48 items: 40 stressors, 3 opportunities to identify negative events that were not asked about, and 5 positive events intended to provide a slight bupliftQ at the end of the study. Respondents indicated whether they experienced each event during the past 6 months. Three judges rated whether each event was relevant to sociotropy concerns, autonomy concerns, or nei-
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ther. Cohen’s kappa, extended to three judges (Fleiss, 1971), was 0.89. When there was not uniform agreement, the two agreeing judges categorized the event. Twenty-one stressors and one positive event were related to sociotropy, eighteen stressors and two positive events to autonomy, and one stressor and two positive events to neither. The 53 responses to openended items were similarly coded. Cohen’s kappa was 0.83. There were no open-ended responses or standard items where all three judges disagreed. Across all items Cohen’s kappa was 0.87. 1.3.3. Montgomery A˚ sberg Depression Rating Scale (Montgomery and A˚ sberg, 1979) This 10-item clinician rating scale assesses depressive symptoms and is sensitive to change. Items are rated from 0 (none) to 6 (severe). It has good interrater reliability (ICC=0.89 to 0.97) (Montgomery and ˚ sberg, 1979) and good internal consistency A (a=0.86) (Maier and Phillipp, 1985).
2. Results 2.1. Reliability of the personal style inventory The test–retest correlations for both sociotropy and autonomy were high (r=0.83 and r=0.80, both pV0.0001). Cronbach’s alpha was 0.85 at time 1 and
0.90 at time 2 for sociotropy, and 0.85 at both times for autonomy. Correlations between MADRS changes and PSI changes examined the effects of depression on PSI reporting. These correlations were quite low and not significant. 2.2. Comparison of depression subtypes Vascular depression was considered present if either deep white matter hyperintensities or subcortical grey matter hyperintensities were measured at 2 or greater on the Coffey scale (Krishnan et al., 1998). The vascular depression group (n=33) did not differ from the non-vascular group (n=16) (see Table 1). Depression was considered early onset if the first episode of depression occurred at or before the age of 50. The late-onset group (n=23) did not differ from the early-onset group (n=32) (see Table 1). 2.3. Examination of clinical control variables Time 2 MADRS scores were not correlated with age, years of education, number of depressive episodes, or age of onset of first episode. Independent t-tests revealed no differences in Time 2 MADRS scores as a function of gender, race, retirement status, or marital status. Therefore, no covariates beyond Time 1 MADRS score were entered in the regression analyses.
Fig. 1. Changes in depression level as a function of the interaction of sociotropy and negative interpersonal events.
J.Q. Morse, C.J. Robins / Journal of Affective Disorders 84 (2005) 25–31
2.4. Regressions predicting change in depression 2.4.1. Sociotropy and negative interpersonal events Initial MADRS score strongly predicted Time 2 MADRS score (b=0.40, sr2=0.16, t =3.15, pV0.001). After controlling for initial MADRS, Time 2 MADRS score was not related to sociotropy or negative interpersonal events, but was related to their congruent interaction (b=0.30, sr2=0.07, t =2.12, p=0.05). This interaction was probed by examining the relation of events to depression at sociotropy scores one S.D. above the mean, one S.D. below the mean, and at the mean. The positive relation between negative interpersonal events and increase in MADRS scores was only significant for high sociotropy scores (b=0.37, t =2.24, pV0.05), not low or average scores (see Fig. 1). 2.4.2. Autonomy and negative autonomy events Time 2 MADRS score was not related to autonomy or negative autonomy events, but was related to their congruent interaction (b=0.28, sr2=0.06, t =2.21, pV0.05). When this interaction was probed, the positive relation between negative autonomy events and increase in MADRS scores was significant for high autonomy scores (b=0.58, t =3.49, pV0.001) and average autonomy scores (b=0.30, t =2.55, pV0.05) (see Fig. 2).
29
2.4.3. Autonomy and negative interpersonal events and sociotropy and negative autonomy events The non-congruent interactions were not related to change in MADRS score.
3. Discussion This study sought to predict increase in depressive symptoms from the interaction between personality characteristics and classes of life events. Supporting our hypothesis, older adult patients in remission who experienced life events that matched their personality experienced greater increases in depressive symptoms over 6 months, suggesting that the personality–life event congruence model has value in understanding late-life depression. The current findings also provide preliminary evidence on the reliability and validity of the Personal Style Inventory in older adults. PSI scores were stable over 6 months, had good internal consistency and were relatively unaffected by changes in depressive symptoms. These findings are similar to psychometric statistics reported in adult clinical samples (Bagby et al., 2001) and suggest that the PSI is a reliable measure of sociotropy and autonomy in older adults.
Fig. 2. Changes in depression level as a function of the interaction of autonomy and negative autonomy events.
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3.1. Limitations Research on stressful life events is hampered by the difficulty of classifying events into meaningful categories (Kwon and Whisman, 1998). Although the judges demonstrated high interrater reliability, their ratings were independent of the context in which the individual experienced that event. For example, retiring from work, categorized as related to autonomy, may be viewed by the individual as impacting relationships with colleagues, thus related to sociotropy. However, participant ratings of an event’s impact confound person and environment variables, which is problematic when testing for person–environment interaction effects. Gender is also a factor to consider as the meaning of retirement is based more on affinitive loss for women than for men. Unfortunately, the sample size precluded examining gender differences. There is no solution other than to recognize that these findings are based on independent raters’ judgments of life events that are separate from the meanings they may have for the participants. There are several subtypes of late-life depression— early onset versus late onset and vascular versus nonvascular. The personality–life event congruence effect may apply differently in these groups. Despite having information about age of onset and vascular status, the power in the current sample was not sufficient to test three-way interactions made up by personality style, life event, and depression subtype. Future research should investigate the usefulness of the interaction between personality and life events in predicting depression in these groups. 3.2. Clinical implications The personality–life event congruence hypothesis brings a theoretical framework to understanding latelife depression. In addition, in adult samples, autonomy scores have predicted positive response to antidepressants (Peselow et al., 1992; Scott et al., 1996). Older adults often have increased risk of drug interactions because of comorbid medical illnesses; it may be helpful to predict response to antidepressants by assessing personality. In terms of psychotherapy, once assessed, it may be possible to help the patient to decrease sociotropy or autonomy concerns through
cognitive therapy or other approaches. It may also be useful to increase a patient’s awareness of the types of events to which he or she is most vulnerable, as a step toward decreasing their frequency or developing coping skills for reducing their negative impact.
Acknowledgement This paper is based on a doctoral dissertation submitted to Duke University by Jennifer Morse, supervised by Clive Robins. Jennifer Morse thanks the other members of her dissertation committee, John F. Curry, Thomas R. Lynch, and David C. Steffens for their support of this project. The research was supported by a GlaxoWellcome Long Term Care Career Development Award to Jennifer Morse through the Leadership in Aging Program at Duke University. The larger study was supported by NIMH grants P50 MH60451, P30 MH40159, and R01 MH 54846. Manuscript preparation was supported in part by NIMH grant T32 MH 18269, Clinical Research Training for Psychologists (PI: Paul A. Pilkonis). We thank David Steffens for offering the resources of the Mental Health Clinical Research Center for the Study of Depression in Late Life at Duke University Medical Center and Carrie Dombeck, Ronna Holliday, Bobby Levy, Stephanie Levy, and Elena Lopez for their help in collecting data.
References Abrams, R.C., Young, R.C., Alexopoulos, G.S., Holt, J.H., 1991. Neuroticism may be associated with history of depression in the elderly. Int. J. Geriatr. Psychiatry 6, 483 – 488. Allen, N.B., Ames, D., Layton, T., Bennetts, K., Kingston, K., 1997. The relationship between sociotropy/autonomy and patterns of symptomology in the depressed elderly. J. Clin. Psychol. 36, 121 – 132. Arieti, S., Bemporad, J.R., 1980. The psychological organization of depression. Am. J. Psychiatry 137, 1360 – 1365. Bagby, R.M., Gilchrist, E.J., Rector, N.A., Dickens, S.E., Joffe, R.T., Levitt, A., Levitan, R.D., Kennedy, S.H., 2001. The stability and validity of the sociotropy and autonomy personality dimensions as measured by the Revised Personal Style Inventory. Cogn. Ther. Res. 25, 765 – 779. Beck, A.T., 1983. Cognitive therapy of depression: new perspectives. In: Clayton, P.J., Barrett, J.E. (Eds.), Treatment of Depression: Old Controversies and New Approaches. Raven Press, New York, pp. 265 – 290.
J.Q. Morse, C.J. Robins / Journal of Affective Disorders 84 (2005) 25–31 Bieliauskas, L.A., Conte, M.A., Glandon, G.L., 1995. Inventorying stressing life events as related to health change in the elderly. Stress Med., 11. Blatt, S.J., 1974. Levels of object representation in anaclitic and introjective depression. Psychoanal. Study Child 29, 7 – 157. Bowlby, J., 1977. The making and breaking of affectional bonds: I. Aetiology and psychopathology in the light of attachment theory. Br. J. Psychiatry 130, 201 – 210. Emmerson, J.P., Burvill, P.W., Finlay-Jones, R., Hall, W.D., 1989. Life events, life difficulties and confiding relationships in the depressed elderly. Br. J. Psychiatry 155, 787 – 792. Fleiss, J.L., 1971. Measuring nominal scale agreement among many raters. Psychol. Bull. 76, 378 – 382. Folstein, M.F., Folstein, S.W., McHugh, P.R., 1975. bMini-mental stateQ: a practical method for grading the cognitive state of patients for the clinician. J. Psychiatr. Res. 12, 189 – 198. George, L.K., Blazer, D.G., Hughes, D.C., Fowler, N., 1989. Social support and the outcome of major depression. Br. J. Psychiatry 154, 478 – 485. Hammen, C., Ellicott, A., Gitlin, L., Jamison, K.R., 1989. Sociotropy/autonomy and vulnerability to specific life events in patients with unipolar depression and bipolar disorders. J. Abnorm. Psychol. 98, 145 – 160. Kraaij, V., Kremmers, E., Arensman, E., Kerhof, A.J.F.M., 1998. Life events over the life cycle and depression in late life. In: Kosky, R.J., Eshkevari, H.S., Goldney, R.D., Hassan, R. (Eds.), Suicide Prevention: The Global Context. Plenum Press, New York, pp. 163 – 166. Krishnan, K.R.R., Hays, J.C., George, L.K., Blazer, D.G., 1998. Six-month outcomes for MRI-related vascular depression. Depress. Anxiety 8, 142 – 146. Kwon, P., Whisman, M.A., 1998. Sociotropy and autonomy as vulnerabilities to specific life events: issues in life event categorization. Cogn. Ther. Res. 22, 353 – 362.
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Lynch, T.R., Robins, C.J., Morse, J.Q., 2001. Couple functioning in depression: the roles of sociotropy and autonomy. J. Clin. Psychol. 57, 93 – 103. Maier, W., Phillipp, M., 1985. Comparative analysis of observer depression scales. Acta Psychiatr. Scand. 72, 239 – 254. Mazure, C.M., Maciejewski, P.K., Jacobs, S.C., Bruce, M.L., 2002. Stressful life events interacting with cognitive/personality styles to predict late-onset major depression. Am. J. Geriatr. Psychiatry 10, 297 – 304. Montgomery, S.A., 2sberg, M., 1979. A new depression scale designed to be sensitive to change. Br. J. Psychiatry 134, 382 – 389. Oldehinkel, A.J., Bouhuys, A.L., Brilman, E.I., Ormel, J., 2001. Functional disability and neuroticism as predictors of late-life depression. Am. J. Geriatr. Psychiatry 9, 241 – 248. Peselow, D.E., Robins, C.J., Sanfilipo, M.P., Block, P., Fieve, R.R., 1992. Sociotropy and autonomy: relationship to antidepressant drug treatment response to endogenous–nonendogenous dichotomy. J. Abnorm. Psychol. 101, 479 – 486. Robins, C.J., Ladd, J., Welkowitz, J., Blaney, P.H., Diaz, R., Kutchner, G., 1994. The personal style inventory: preliminary validation studies of new measures of sociotropy and autonomy. J. Psychopathol. Behav. Assess. 16, 277 – 300. Scott, J., Harrington, J., House, R., Ferrier, I.N., 1996. A preliminary study of the relationship among personality, cognitive vulnerability, symptom profile, and outcome in major depressive disorder. J. Nerv. Ment. Dis. 184, 503 – 505. Segal, Z.V., Shaw, B.F., Vella, D.D., Katz, R., 1992. Cognitive and life stress predictors of relapse in remitted unipolar depressed patients: test of the congruency hypothesis. J. Abnorm. Psychol. 101, 26 – 36.
Research report
Personality–life event congruence effects in late-life depression Jennifer Q. Morsea,*, Clive J. Robinsa,b a
Department of Psychology, Social and Health Sciences, Duke University, United States b Department of Psychiatry and Behavioral Sciences, Duke University, United States Received 10 February 2004; accepted 14 September 2004
Abstract Background: This study examined whether specific interactions of personality and life events predicted increases in depressive symptoms over time in a late-life sample. Method: Participants (n=55) who were in remission from a recent episode of major depression completed a depression symptom interview and a questionnaire assessing the personality constructs sociotropy and autonomy. Six months later, they completed the same personality questionnaire and a checklist of life events experienced during the past 6 months. Results: As predicted, increases in depressive symptoms were significantly predicted by the congruent interaction of sociotropy with negative interpersonal events and by the congruent interaction of autonomy with negative autonomy events, but not by either of the non-congruent interactions. Limitations: A small sample prevented examinations of important depressive subtypes based on age of depression onset and vascular status. Conclusions: These findings strongly support the personality–life event congruence model of depression in a late-life sample. Clinical implications include attending to stressful events that match an older adult’s personality style, to help the older adult cope with those events that are more likely to increase his or her depression. D 2004 Elsevier B.V. All rights reserved. Keywords: Late-life depression; Personality; Life events
Cognitive and psychoanalytic theories have converged on a similar theoretical framework describing personality characteristics that create vulnerability to depression following negative life events that are * Corresponding author. Now at Personality Studies, Western Psychiatric Institute and Clinic, 3811 O’Hara Street, Pittsburgh, PA 15213, United States. Tel.: +1 412 246 5838; fax: +1 412 246 5840. E-mail address: [email protected] (J.Q. Morse). 0165-0327/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jad.2004.09.007
congruent with those characteristics. Empirical studies of adult samples have supported this congruence hypothesis. While research on late-life depression has addressed its association with life events and personality, only one study has examined the role of interactions between personality characteristics and life events. Depression in late-life can have unique features, such as involvement of vascular disease, so the results with adult samples cannot necessarily be
26
J.Q. Morse, C.J. Robins / Journal of Affective Disorders 84 (2005) 25–31
generalized to late-life depression. This paper reports the results of an empirical test of the personality–life event congruence effect in a late-life sample. Theorists have suggested that normal personality development requires both interpersonal connection and self-definition (Arieti and Bemporad, 1980; Beck, 1983; Blatt, 1974; Bowlby, 1977) and that overemphasis on either theme creates vulnerability to depression, particularly following matching stressful life events. Highly sociotropic (Beck, 1983) or dependent (Blatt, 1974) people value close relationships, which may leave them vulnerable to depression after negative interpersonal events. Autonomous (Beck, 1983) or self-critical (Blatt, 1974) people value independence, mastery and control, which may leave them vulnerable to depression after perceived loss of control or failure. The interaction between sociotropy or autonomy and matching events predicts depressive relapse in adults (Hammen et al., 1989; Segal et al., 1992). Research on late-life depression has focused on main effects of life events or personality factors. There is a positive relation between depressive symptoms in older adults and negative life events (Kraaij et al., 1998). Clinically depressed patients reported both more frequent and more severe life events than did control groups (Emmerson et al., 1989). In terms of personality, neuroticism has received the most attention in late life. Neuroticism is related to greater depressive symptoms (Abrams et al., 1991) and predicts increased risk of developing late-life depression (Oldehinkel et al., 2001). Sociotropy and autonomy both correlate significantly with depressive symptoms in older adults (Allen et al., 1997). Thus, there is evidence linking both life events and personality to late-life depression, but the magnitude of these effects was modest and it is possible that interactions between personality and life events account for additional variance in depression in older adults. In the lone study investigating the interaction between personality and life events in late-life depression, Mazure et al. (2002) compared 42 late-onset depressed outpatients with 42 non-depressed elderly matched controls. Depressed group membership was associated both with the interaction between sociotropy and negative events and with the interaction between autonomy and negative events, which was interpreted as support for the congruence hypothesis. However, the event measure was nonspecific, rather than differ-
entiated into interpersonal and autonomy events, so it does not test the congruence hypothesis. And the study’s cross-sectional case-control design makes it impossible to infer causal directionality. The current study, in contrast, is prospective, testing the ability of the congruence hypothesis to predict the return of symptoms in a sample of patients who were in remission from a major depressive episode. In this study, we assessed sociotropy, autonomy, and depressive symptoms in a group of older adult patients who were in remission from a recent episode of major depressive disorder and reassessed depressive symptoms and recent life events 6 months later. Our primary hypothesis was that congruent interactions between the two personality variables and types of events would be associated with increases in depressive symptoms over the 6-month period.
1. Method 1.1. Participants Participants were recruited from a longitudinal study at the NIMH Clinical Research Center (CRC) for the Study of Depression in Late Life at Duke University. For inclusion in the CRC study, subjects met criteria for major depressive episode using the Duke Depression Evaluation Schedule for the Elderly (George et al., 1989) and had a Mini-Mental Status Exam (Folstein et al., 1975) score z25. For inclusion in the current study, participants had to be in remission, defined as Montgomery 2sberg Depression Rating Scale (Montgomery ˚ sberg, 1979) score V10. Patients with recent and A MMSE b25, a diagnosis of Alzheimer’s disease, or receiving electroconvulsive therapy were excluded. Seventy-two patients who met these criteria completed the initial assessment; 15 (21%) did not complete the second assessment and 2 (3%) had invalid data, based on visual inspection of the questionnaires following regression diagnostics. The demographics of the final sample are described in Table 1.1 1
Participants who completed the second survey (n=55) did not differ from those who did not (n=15) except for having lower MMSE error scores than non-completers (completers: M=1.06, S.D.=1.33, non-completers: M=1.88, S.D.=1.80, t(67)= 2.02, p=0.05) at CRC entry.
J.Q. Morse, C.J. Robins / Journal of Affective Disorders 84 (2005) 25–31
27
Table 1 Sample demographics and comparing depressive subgroups Overall (n=55)
Late onset (n=23)
Early onset (n=32)
v 2 (df)
Non-vascular (n=16)a
Vascular (n=33)
v 2 (df)
%Women %Married %Minority
64 64 7
69 66 3
57 61 13
0.87 (1) 0.13 (1) 1.95 (1)
63 69 13
64 58 6
0.01 (1) 0.57 (1) 0.60 (1)
t (df)
Mean (S.D.)
Mean (S.D.)
t (df)
Age Years of education Age of onset # previous episodes MMSE errors Deep white matter hyperintensities Subcortical hyperintensities Time 1 MADRS Time 2 MADRS Time 1 sociotropy Time 1 autonomy Time 2 sociotropy Time 2 autonomy Negative interpersonal events Negative autonomy events
68.09 14.37 46.70 4.27 1.06 1.53
Mean (S.D.)
1.31 (1.08) 2.60 5.07 86.00 77.63 86.63 78.95 1.93
Mean (S.D.)
(6.82) 67.96 (7.05) (2.27) 14.23 (2.29) (18.76) 65.77 (7.87) (5.04) 2.00 (1.55) (1.33) 1.18 (1.40) (1.01) 1.71 (1.19)
(3.20) (5.30) (14.09) (13.71) (15.98) (13.89) (2.01)
1.78 (1.54)
1.62 (1.12) 2.70 4.26 85.78 78.19 84.96 80.13 1.96
(3.65) (5.24) (15.21) (13.88) (14.66) (12.67) (2.34)
1.52 (1.47)
Mean (S.D.) 68.19 14.47 33.59 5.96 0.97 1.39
(6.76) (2.29) (11.15) (6.03) (1.30) (1.03)
1.07 (1.02) 2.53 5.66 86.15 77.23 87.84 78.07 1.91
(2.90) (5.35) (13.48) (13.79) (16.99) (14.87) (1.77)
1.97 (1.58)
0.12 (53) 66.50 (5.66) 68.39 (7.43) 0.38 (52) 14.38 (1.86) 14.52 (2.36) 11.67 (52)**** 44.81 (19.24) 47.85 (19.74) 4.11b **** 5.13 (7.81) 3.93 (3.50) 0.57 (50) 1.13 (1.64) 1.09 (1.28) 1.01 (47) 0.63 (0.50) 1.97 (1.05) 1.79 (47) 0.19 0.96 0.10 0.26 0.66 0.54 0.09
(53) (53) (53) (53) (53) (52) (53)
1.07 (53)
0.19 (0.40) 2.25 3.81 84.67 79.69 85.22 79.19 2.13
(2.70) (4.25) (14.65) (10.29) (18.35) (8.56) (2.03)
1.69 (1.62)
1.85 (0.87) 2.88 5.42 87.25 77.60 87.04 79.43 2.00
(3.34) (5.61) (14.42) (14.99) (16.18) (16.57) (2.11)
1.97 (1.49)
0.99 (38.11) 0.21 (47) 0.51 (47) 0.82b 0.09 (45) 6.09 (47)**** 9.13 (46.97)**** 0.66 1.01 0.58 0.50 0.35 0.05 0.20
(47) (47) (47) (47) (47) (46) (47)
0.60 (47)
a
MRI data were missing for six participants. Mann–Whitney U reported. **** pb0.0001.
b
1.2. Procedure At each appointment, a psychiatrist assessed depressive symptoms by interview. Subjects who were in remission were mailed the Personal Style Inventory (PSI, Robins et al., 1994) and received $3 for completing it. After a psychiatrist appointment 6 months later, participants completed the PSI and the Modified Schedule of Life Events (Bieliauskas et al., 1995) and received $15. Demographic and clinical information came from baseline CRC assessments. 1.3. Measures 1.3.1. Personal style inventory (Robins et al., 1994) This 48-item self-report measure assesses the key concerns of sociotropy and autonomy. Both scales have good internal consistency in depressed sam-
ples—sociotropy: a=0.83, autonomy: a=0.79 (Lynch et al., 2001), but the psychometric properties of the PSI among older adults are not known. 1.3.2. Schedule of life events—modified (Bieliauskas et al., 1995) This inventory of 48 negative and 6 positive life events was constructed for use with older adults. It has been modified for the present study. Details regarding the modification are available from the first author. The modified measure includes 48 items: 40 stressors, 3 opportunities to identify negative events that were not asked about, and 5 positive events intended to provide a slight bupliftQ at the end of the study. Respondents indicated whether they experienced each event during the past 6 months. Three judges rated whether each event was relevant to sociotropy concerns, autonomy concerns, or nei-
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ther. Cohen’s kappa, extended to three judges (Fleiss, 1971), was 0.89. When there was not uniform agreement, the two agreeing judges categorized the event. Twenty-one stressors and one positive event were related to sociotropy, eighteen stressors and two positive events to autonomy, and one stressor and two positive events to neither. The 53 responses to openended items were similarly coded. Cohen’s kappa was 0.83. There were no open-ended responses or standard items where all three judges disagreed. Across all items Cohen’s kappa was 0.87. 1.3.3. Montgomery A˚ sberg Depression Rating Scale (Montgomery and A˚ sberg, 1979) This 10-item clinician rating scale assesses depressive symptoms and is sensitive to change. Items are rated from 0 (none) to 6 (severe). It has good interrater reliability (ICC=0.89 to 0.97) (Montgomery and ˚ sberg, 1979) and good internal consistency A (a=0.86) (Maier and Phillipp, 1985).
2. Results 2.1. Reliability of the personal style inventory The test–retest correlations for both sociotropy and autonomy were high (r=0.83 and r=0.80, both pV0.0001). Cronbach’s alpha was 0.85 at time 1 and
0.90 at time 2 for sociotropy, and 0.85 at both times for autonomy. Correlations between MADRS changes and PSI changes examined the effects of depression on PSI reporting. These correlations were quite low and not significant. 2.2. Comparison of depression subtypes Vascular depression was considered present if either deep white matter hyperintensities or subcortical grey matter hyperintensities were measured at 2 or greater on the Coffey scale (Krishnan et al., 1998). The vascular depression group (n=33) did not differ from the non-vascular group (n=16) (see Table 1). Depression was considered early onset if the first episode of depression occurred at or before the age of 50. The late-onset group (n=23) did not differ from the early-onset group (n=32) (see Table 1). 2.3. Examination of clinical control variables Time 2 MADRS scores were not correlated with age, years of education, number of depressive episodes, or age of onset of first episode. Independent t-tests revealed no differences in Time 2 MADRS scores as a function of gender, race, retirement status, or marital status. Therefore, no covariates beyond Time 1 MADRS score were entered in the regression analyses.
Fig. 1. Changes in depression level as a function of the interaction of sociotropy and negative interpersonal events.
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2.4. Regressions predicting change in depression 2.4.1. Sociotropy and negative interpersonal events Initial MADRS score strongly predicted Time 2 MADRS score (b=0.40, sr2=0.16, t =3.15, pV0.001). After controlling for initial MADRS, Time 2 MADRS score was not related to sociotropy or negative interpersonal events, but was related to their congruent interaction (b=0.30, sr2=0.07, t =2.12, p=0.05). This interaction was probed by examining the relation of events to depression at sociotropy scores one S.D. above the mean, one S.D. below the mean, and at the mean. The positive relation between negative interpersonal events and increase in MADRS scores was only significant for high sociotropy scores (b=0.37, t =2.24, pV0.05), not low or average scores (see Fig. 1). 2.4.2. Autonomy and negative autonomy events Time 2 MADRS score was not related to autonomy or negative autonomy events, but was related to their congruent interaction (b=0.28, sr2=0.06, t =2.21, pV0.05). When this interaction was probed, the positive relation between negative autonomy events and increase in MADRS scores was significant for high autonomy scores (b=0.58, t =3.49, pV0.001) and average autonomy scores (b=0.30, t =2.55, pV0.05) (see Fig. 2).
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2.4.3. Autonomy and negative interpersonal events and sociotropy and negative autonomy events The non-congruent interactions were not related to change in MADRS score.
3. Discussion This study sought to predict increase in depressive symptoms from the interaction between personality characteristics and classes of life events. Supporting our hypothesis, older adult patients in remission who experienced life events that matched their personality experienced greater increases in depressive symptoms over 6 months, suggesting that the personality–life event congruence model has value in understanding late-life depression. The current findings also provide preliminary evidence on the reliability and validity of the Personal Style Inventory in older adults. PSI scores were stable over 6 months, had good internal consistency and were relatively unaffected by changes in depressive symptoms. These findings are similar to psychometric statistics reported in adult clinical samples (Bagby et al., 2001) and suggest that the PSI is a reliable measure of sociotropy and autonomy in older adults.
Fig. 2. Changes in depression level as a function of the interaction of autonomy and negative autonomy events.
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3.1. Limitations Research on stressful life events is hampered by the difficulty of classifying events into meaningful categories (Kwon and Whisman, 1998). Although the judges demonstrated high interrater reliability, their ratings were independent of the context in which the individual experienced that event. For example, retiring from work, categorized as related to autonomy, may be viewed by the individual as impacting relationships with colleagues, thus related to sociotropy. However, participant ratings of an event’s impact confound person and environment variables, which is problematic when testing for person–environment interaction effects. Gender is also a factor to consider as the meaning of retirement is based more on affinitive loss for women than for men. Unfortunately, the sample size precluded examining gender differences. There is no solution other than to recognize that these findings are based on independent raters’ judgments of life events that are separate from the meanings they may have for the participants. There are several subtypes of late-life depression— early onset versus late onset and vascular versus nonvascular. The personality–life event congruence effect may apply differently in these groups. Despite having information about age of onset and vascular status, the power in the current sample was not sufficient to test three-way interactions made up by personality style, life event, and depression subtype. Future research should investigate the usefulness of the interaction between personality and life events in predicting depression in these groups. 3.2. Clinical implications The personality–life event congruence hypothesis brings a theoretical framework to understanding latelife depression. In addition, in adult samples, autonomy scores have predicted positive response to antidepressants (Peselow et al., 1992; Scott et al., 1996). Older adults often have increased risk of drug interactions because of comorbid medical illnesses; it may be helpful to predict response to antidepressants by assessing personality. In terms of psychotherapy, once assessed, it may be possible to help the patient to decrease sociotropy or autonomy concerns through
cognitive therapy or other approaches. It may also be useful to increase a patient’s awareness of the types of events to which he or she is most vulnerable, as a step toward decreasing their frequency or developing coping skills for reducing their negative impact.
Acknowledgement This paper is based on a doctoral dissertation submitted to Duke University by Jennifer Morse, supervised by Clive Robins. Jennifer Morse thanks the other members of her dissertation committee, John F. Curry, Thomas R. Lynch, and David C. Steffens for their support of this project. The research was supported by a GlaxoWellcome Long Term Care Career Development Award to Jennifer Morse through the Leadership in Aging Program at Duke University. The larger study was supported by NIMH grants P50 MH60451, P30 MH40159, and R01 MH 54846. Manuscript preparation was supported in part by NIMH grant T32 MH 18269, Clinical Research Training for Psychologists (PI: Paul A. Pilkonis). We thank David Steffens for offering the resources of the Mental Health Clinical Research Center for the Study of Depression in Late Life at Duke University Medical Center and Carrie Dombeck, Ronna Holliday, Bobby Levy, Stephanie Levy, and Elena Lopez for their help in collecting data.
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