INT'L. J. AGING AND HUMAN DEVELOPMENT,VOI.35(3) 193-204,1992
DEVELOPMENT OF AN INTERVIEW-BASED GERIATRIC DEPRESSION RATING SCALE
CHRISTINEJAMISON FORREST SCOGIN University of Alabama, Tuscaloosa
ABSTRACT
The geriatric depression rating scale (GDRS) is a new interview-based depression rating scale designed for use with adults 60 years of age or older. The scale was developed to fill a need for an instrument that would be sensitive to the problems encountered in assessing depression among older adults. The GDRS was designed by using items from the self-report Geriatric Depression Scale (GDS) as topic areas in a structured clinical interview similar to that of the Hamilton Rating Scale for Depression (HRSD). The 35-item rating scale was administered to 68 older individuals with a range of affective disturbance. The scale was found to have internal consistency and split-half reliability comparable to the HRSD and GDS. Concurrent validity, construct validity, external criterion validity, sensitivity, and specificity were all found to be acceptable.
Older adults are exposed to many stressors such as loss of relatives and friends through death, through mandatory retirement, declining physical health, and poorer cognitive functioning. Depression can follow these losses. Surveys have indicated that depression is a common problem among older adults with approximately two to seven percent of the older adult population being clinically depressed [l,21. The diagnosis of depression among older adults is often difficult. Many older adults have physical problems which confound somatic indicators of depression such as sleep problems, weight loss, fatigue, and irritability [3]. Further complicating the diagnosis are complaints about memory losses, 193 0 1992, Baywood Publishing Co., Inc.
doi: 10.2190/0803-3FBC-6EB0-ACH4 http://baywood.com
194 / JAMISON AND SCOGIN
confusion, and inability to concentrate. These symptoms make differentiation between depression and the early stages of dementias difficult [4]. Further complicating the picture, the early stages of dementia are often accompanied by depression as patients become aware of cognitive losses. These concerns prompted the development of the Cornell Scale for Depression in Dementia [ 5 ] , an instrument designed for assessing depression severity in patients evidencing irreversible or reversible dementia. However, the reliance on collateral sources of information make it less attractive for use with most communitydwelling older adults. One of the widely used interview schedules for depression research is the Hamilton Rating Scale for Depression [6]. The popularity of the HRSD is attributed to its brevity in administration (30 minutes), its agreement in ratings among clinicians [7], and its sensitivity to change in depressive severity [8, 91. However, the HRSD has several disadvantages such as less than specific rating guidelines [lo, 111 and heavy reliance on somatic indicators of depression [4, 8, 91. Yesavage, Brink, Rose, and Adey [12] also note the need for geriatric depression scales. They observe that the HRSD is a widely accepted instrument, but one not originally designed for use with older adults and lacking in validation with this group. Petrie [13] recommends that the HRSD be used “very prudently” with older patients. The HRSD’s heavy loading of somatic items presents, in particular, a problem when assessing older adults [4, 81. Gallagher and Thompson [4] describe the difficulty in discriminating between physical complaints due to health related problems and those due to depression when using the HRSD. They comment that the difficulty derives from artificially high HRSD scores for older adults unless the interviewer uses additional information concerning the individuals’ health status to modify HRSD scores [4]. Gallagher [8] concludes her review of the HRSD by commenting that “our research group cannot heartily recommend the HRSD . . . ” (pg. 210). The Geriatric Depression Rating Scale (GDRS) was developed to fill the need for a rating scale which is sensitive to the special problems encountered in assessing depression in older adults. More specifically, we were interested in developing a brief, yet thorough scale to assess depression in older adults. The GDRS was modeled after an already popular self-rating Geriatric Depression Scale [GDS, 31. Further, our research plan called for validation of the instrument with a heterogeneous crosssection of older adults, adding to the generalizability of the instrument. Finally, we planned to provide a detailed instruction manual for raters, providing for potentially greater concordance between raters across research settings. Although the GDRS includes somatic items to conform to Research Diagnostic Criteria [RDC; 141, the instrument does not rely on them heavily and specifications for rating the somatic items are detailed in the manual. In addition, the GDRS includes cognitive items such as memory problems, difficulty in concentration, and mental clarity which are thought to be linked to depression in older adults [15, 161.
GERIATRIC DEPRESSION / 195
METHOD
Item Developmentand Instruments Used Two depression instruments which are in current use are the Hamilton Rating Scale for Depression [HRSD; 61 and the Geriatric Depression Scale [GDS; 31. The HRSD was developed to quantify interviews so that treatment progress and outcome could be assessed once a person was diagnosed as depressed. The clinician rates depression using an interview format, and thus, the HRSD possesses the capacity to assess people who cannot answer a self-report measure due to severity of illness or inability to read [6]. The GDS [3] is a self-report measure of depression that was designed as a screening device specifically for use with older adults. The final version includes 30 items (out of 100 original items) which correlate with symptoms of depression. Somatic items were excluded as they did not correlate with depressive symptoms [3]. The GDRS, a 35-item instrument, was designed as a research tool to assess the effects of treatment for depression in older adults. Twenty-nine of the items on the GDRS were developed by using the 30 items on the GDS as topic areas for discussion in an interview. Among the items included are life satisfaction, relative well-being, participation in activities and interests, morning mood, ability to concentrate, and hopefulness. Ratings are made on a 0-4 scale with higher scores indicating greater severity. Six somatic items were added to conform to Research Diagnostic Criteria [14]. They are early, middle, and late insomnia; weight loss, changes in appetite, and somatic anxiety symptoms. A detailed manual was developed to instruct and guide the interviewer in reliable scoring of the 35 items. Scores on the GDRS can range from 0 to 132. A summary of the content areas covered in the HRSD, GDS, and GDRS is presented in Table 1.
Sample Description The sample consisted of 19 older adults solicited from the community, 24 individuals from a depression treatment study, and 25 individuals who were referred for depression assessment from a VA hospital. These groups were chosen to represent a cross-section of older adults likely to be assessed for depression. The criterion for participation in the study was that participants must be aged 60 or older, although there was one participant aged 58. Table 2 contains demographic characteristics of the sample. In addition to the demographic information, a mental status quotient and a health status rating were obtained for each participant. The mental status quotient was obtained using the Mental Status Questionnaire [17]. On a scale from 0 (not oriented) to 10 (fully oriented), the mean score for the sample was 8.96 (SO = 1.61). To obtain a health status rating, participants were asked to self-rate their health status on a scale of 0 @oar health)
196 I JAMISON AND SCOGIN
Table 1. Content of Items Comprising the HRSD, GDS, and GDRS
HRSDB
GDS~
GDRS'
1. Depressed mood 2. Feelings of guilt 3. Suicide 4. Insomnia early 5. Insomnia middle 6. Insomnia late 7. Work and activities 8. Psychomotor retardation 9. Agitation 10. Anxiety psychic 11. Anxiety somatic 12. Appetite 13. Fatiguability 14. Genital symptoms 15. Hypochondriasis 16. Loss of weight 17. Insight 18. Diurnal variation 19. Depersonalization 20. Paranoid symptoms 21. Obsessional and compulsive symptoms 22. 23. 24. 25. 26. 27. 28.
Life satisfaction Activities and interests Empty life Boredom Hopeful 0bsessions Good sprits Catastrophic fear
Good spirits Life satisfaction Exciting life Boredom Relative well-being Activities and interests Initiating projects Insomnia early
Happy Hopeless Restlessness Stay at home Future worry Memory problems Suicidal Blue Worthlessness Past worry Exciting life Initiating projects Energy
Insomnia middle Insomnia late Morning mood Energy level Appetite Loss of weight Stay at home Sociality Decision making Concentration Memory problems Mental clarity Hopefulness
Hopelessness Relative well-being Upset Crying Concentration Morning mood Sociality
29. 30. 31. 32. 33. 34. 35.
Decision making Mental clarity
Future worry Catastrophic fear Obsessions Upset Anxiety somatic Restless Psychomotor retardation Past worry Worthlessness Emptiness Blue Crying Hopelessness Suicidal
GERIATRIC DEPRESSION / 197
Table 2. Demographic Characteristics of Sample Variable Age Years of Education Annual Income in thousands Sex Male Female Race White Black Marital Status Married Widowed Divorced Single
M
SD
70.91 13.19 17.00
6.30 3.22 12.03
n
%
33 35
48 52
61 7
90
38 17 9 4
56 25 13 6
10
to 10 (excellent health). The mean score on the health status rating for the sample was 5.86 (So= 2.27).
Procedure Participants were interviewed at an outpatient mental health facility (except for participants from the VA Hospital who were interviewed at the hospital). Interviews were conducted in therapy rooms in the clinic or in an office at the hospital. Participants were briefly screened for mental status by the interviewer using the Mental Status Questionnaire and were asked to self-rate their health status. They were then given two interview format measures, the HRSD and GDRS, and two self-report measures, the Beck Depression Inventory-short form [ 181 and the GDS. The interviews for depression using the GDRS and the HRSD were conducted first and were alternated as to which was administered first. Immediately following the interviews the participants were given the self-report measures in alternating order. All HRSD and GRSD interviews were conducted by an advanced clinical psychology graduate student after supervised training. GDRS interviews averaged approximately 35 minutes, whereas HRSD interviews lasted approximately 30 minutes on average. The self-report instruments were also distributed by the interviewer. To insure reliability, a random selection of
198 / JAMISON AND SCOGIN
interviews were audio-taped and then were rated by an experienced clinical psychologist. The average percent agreement across items was 86 percent for the GDRS and 80 percent for the HRSD.
RESULTS Item Selection Items were selected on the basis of corrected item to total correlations and the squared multiple correlation coefficients. Using the corrected item to total correlation, six items, item numbers 8, 14, 17, 19, 25, and 31, did not correlate highly with the total score (their item to total correlations were less than .4). These items’ domains were early insomnia, weight loss, difficulty in decision making, memory problems, getting upset over little things, and feelings that life is empty. However, the six items were included because their squared multiple correlations coefficients ranged from 51 to .68 which was well within the acceptable range. Furthermore, when the squared multiple correlation coefficient from a regression model with all 35 items were examined, the instrument was able to explain at least 72 percent of the variability in the depression measure. Therefore, on the basis of these two techniques, all 35 items were retained. Table 3 contains sample items, suggested interviewer questions, and the corresponding rating scale. Reliability Internal consistency was assessed using Cronbach’s alpha coefficient and an alpha coefficient of .92 was obtained. Comparable values for the HRSD and GDS are .90 and .94, respectively [3].The mean inter-item correlation was .24 with a range of 3 6 . The HRSD and GDS have mean inter-item correlations of 3 4 and 3 6 , respectively [3].Split-half reliability for the GDRS was assessed using the Spearman-Brown formula and a coefficient of .89 was obtained. Split-half reliability coefficients for the HRSD and GDS arc .82 and .94, respectively [3 ]. Table 4 presents these internal consistency comparisons. Concurrent Validity The Pearson correlation coefficient was used to assess concurrent validity with the HRSD, BDI and GDS. These coefficients, presented in Table 5, were .83, .69 and .8Srespectively, and all were significant at the .01 level. Discriminate Validity Participants were divided into two groups, depressed and nondepressed, based on their HRSD scores using a cutoff score of 11+as depressed [3 ].The HRSD was chosen as the criterion measure due to its widespread acceptance and use as a
GERIATRIC DEPRESSION / 199
Table 3. Sample Items From the GDRS LIFE SATISFACTION How do you feel about your life? Do you feel you have a good life? Are you basically satisfied with your life? Overall do you find life rewarding? If you could do it over again, would you change anything? 0 = Indicates no dissatisfactionwith life. 1 = Indicates sometimes feeling dissatisfied with life. 2 = Indicates often feeling dissatisfied with life. 3 = Indicates feeling dissatisfied with life most of the time and this interferes with functioning. 4 = Always feels dissatisfied with life.
DECISION MAKING How do you feel about making decisions? Is it easy for you to make decisions? What kinds of decisions are easy for you to make? 0 = Almost always easy to make decisions. 1 = Some difficulty in making decisions. Little or no difficulty in daily functioning. 2 = Seldom easy to make decisions, and this interferes with daily functioning. 3 = Significant problems in functioning due to decision-making difficulties. 4 = Cannot make decisions. Interferes severely with functioning in all areas.
HOPELESSNESS Do you feel hopeless? Is your situation hopeless?
0 = Almost never feels hopeless. 1 = Seldom feels hopeless. 2 = Sometimes feels hopeless. 3 = Often feels hopeless and this interferes with functioning. 4 = Feels hopeless most of the time and this severely affects most areas of functioning.
200 / JAMISON AND SCOGIN
Table 4. Comparisons of Internal Consistency Measures for the GDRS, HRSD, and GDS Index
GDRS~
Mean interim correlation Alpha coefficient Split-half reliability
0.24 0.92 0.89
H R S ~
0.34 0.90 0.82
GDS~
0.36 0.94 0.94
Note: The data in columns 2 and 3 are from "Development and validation of a geriatric depression screening scale: A preliminary report" by J. A. Yesavage, T. L. Brink, T. L. Rose, 0. Lum, V. Huang, M. Adey, and V. 0. Leirer, 1983,Journal of Psychiatric Research, 17, p. 43.Copyright 1983 by Pergamon Press Ltd. Adapted by permission. 'Geriatric Depression Rating Scale bHarnilton Rating Scale for Depression 'Geriatric Depression Scale
Table 5. Pearson Correlation Coefficientsfor HRSD, BDI, GDS, and GDRS
HRSD BDI GDS GDRS
2 < ."'
1.oo
.65* .72* .83*
1.oo
.67* .69*
1.oo .85*
1.oo
Hamilton Rating Scale for Depression bBeck Depression Inventory 'Geriatric Depression Scale dGeriatric Depression Rating Scale
measure of depression. A discriminant function analysis was used to determine if the GDRS discriminated well between depressed and nondepressed participants. The results showed that the GDRS did discriminate between the two groups at the .01 level of significance. Group means and standard deviations are presentcd in Table 6.
Sensitivity and Specificity An important aspect in the development of a depression instrument is determining a cutoff score. There is a tradeoff between sensitivity (correctly identifying depressed people by their scores being equal to or greater than the cutoff score) and specificity (correctly identifying nondepressed people by their scores
GERIATRIC DEPRESSION / 201
being below the cutoff point). A low cutoff score would increase the sensitivity but decrease the specificity. A high cutoff score would decrease the sensitivity but would increase the specificity. Table 7 indicates sensitivity and specificity percents for the various cutoff scores for the GDRS, the HRSD, and the GDS. Participants were divided into two groups (depressed and nondepressed) using a cutoff score of 20+ on the GDRS. This cutoff score yields 88 percent sensitivity and 82 percent specificity. The mean score for the depressed group was 38.64 and
Table 6. Means and Standard Deviations for the Depression Rating Scales as a Function of Classification Classification Rating Scale
Depressed (n = 34)
Nondepressed (n = 34)
37.97 16.14
14.97 8.81
14.97 4.00
5.82 3.05
GDRSa M SD HRSD~ M SD
'Geriatric Depression Rating Scale bHamilton Rating Scale for Depression
Table 7. Cutoff Scores for Sensitivity and Specificity on the GDRS, HRSD, and GDS Criterion Cutoff Scores Sensitivity Specificity
GDRS'
18+ 20+ 22+ 94% 88% 82% 68% 82% 88%
HRSD~
9+ 1 1 + 13+ 88% 86% 73% 75% 80% 85%
GDS~
9+ 11+ 14+ 90% 84% 80% 80% 95% 100%
Note: The data in columns 4 through 9 are from "Screeningtests for geriatric depression" by T. L. Brink, J. A. Yesavage, 0 Lum, P. H. Heersema, M. Adey, and T. L. Rose, 1982, Clinical Gerontologist, 1, p. 42. Copyright 1982 by The Haworth Press, Inc. Adapted by permission. aGeriatric Depression Rating Scale *Hamilton Rating Scale for Depression 'Geriatric Depression Scale
202 / JAMISON AND SCOGIN
the mean score for the nondepressed group was 12.78. A 1-test was performed between the two groups and the results indicated statistically significant differentiation between the groups, t(66) = -9.20,~< .001.
DISCUSSION The results of this investigation indicate that the GDRS has adequate reliability and validity in the measurement of depression in older adults. The GDRS compares favorably with the most popular interview-based measure of depression, the HRSD. Specifically, our results suggest that the GDRS possesses adequate internal reliability, concurrent validity, construct validity, and external criterion validity. Our results do not allow us to claim superiority for the GDRS over the more traditional HRSD. Based solely on psychometric data, the two scales are quite comparable. In fact, in bootstrapping research of this sort, agreement with the traditionally used scale is necessary for validation. However, we suggest that the GDRS has at least two relative advantages over the HRSD. One is that the questions were developed specifically in reference to older adults, more precisely, they build upon the work of Yesavage and colleagues with the GDS. Secondly, we feel that the GDRS will require less rater training and less discretionary decisionmaking on the part of the rater. With these probable advantages, we believe that clinicians and researchers will find the GDRS advantageous to the HRSD. Given the early stage of development of the GDRS, we encourage clinicians and researchers to collect reliability and validity data to aid in validation efforts. Specifically, future research should be directed towards establishing the temporal stability of GDRS ratings through test-retest measures and sensitivity to change exhibited by the scale in longitudinal research. The interviewer reliability achieved by raters not affiliated with the development of the scale is also desirable. The generalizability of the scale would be enhanced by studies of subgroups such as those experiencing physical aliments or elders suffering mild to moderate cognitive impairment. Given the present characteristics of the GDRS, the instrument is appropriate for use in clinical research involving the assessment of depression in older adults.
ACKNOWLEDGMENTS We gratefully acknowledge the assistance of Charles Ward and Kimberly Gochneaur.
REFERENCES 1. I). Blazer and C. D. Williams, Epidemiology of Dysphoria and Depression in an Elderly Population,American Journal of Psychiatry, 137, pp. 439-444,1980.
GERIATRIC DEPRESSION / 203
2. B. J. Gurland, The Comparative Frequency of Depression in Various Adult Age Groups, Journal of Gerontology, 31, pp. 283-292,1976. 3. J. A. Yesavage, T. L. Brink, T. L. Rose, 0. Lum, V. Huang, M. Adey, and V. 0.hirer, Development and Validation of a Geriatric Depression Screening Scale: A Preliminary Report, Journal of Psychiatric Research, 17, pp. 37-49,1983. 4. D. Gallagher and L. W. Thompson, Depression, in Clinical Geropsychology: New Directions in Assessment and Treatment, P. M. Lewinsohn and L. Teri (eds.), Pergamon Press, New York, pp. 7-37,1983. 5. G. S. Alexopoulos, R. C. Abrams, R. C. Young, and C. A. Shamoian, Cornell Scale for Depression in Dementia, Biological Psychiatry, 23, pp. 271-284,1988. 6. M. Hamilton, A Rating Scale for Depression, Journal OfNeurology, Neurosurgery and Psychiatry, 23, pp. 56-62,1960. 7. J. L. Hedlund and B. W. Vieweg, The Hamilton Rating Scale for Depression: A Comprehensive Review, Journal of Operational Psychiatry, 11, pp. 48-65, 1979. 8. D. Gallagher, Assessment of Depression by Interview Methods and Psychiatric Rating Scales, in Handbook of Clinical Memory Assessment of Older Adults, L. W. Poon, T. Crook, K. L. Davis, C. Eisdorfer, B. J. Gurland, A. W. Kaszniak, and L. W. Thompson (eds.), American Psychological Association, Washington, D.C., pp. 202-212,1986. 9. J. G. Rabkin and D. F. Klein, The Clinical Measurement of Depressive Disorders, in The Measurement of Depression, A. J. Marsella, R. M. A. Hirschfeld, and M. M. Katz (eds.), Guilford Press, New York, pp. 30-83,1987. 10. I. W. Miller, S. Bishop, W. H. Noman, and H. Maddever, The Modified Hamilton Rating Scale for Depression: Reliability and Validity, Psychiatry Research, 14, pp. 131-142, 1985. 11. B. F. Shaw, T. M. Vallis, and S. B. McCabe, The Assessment of the Severity and Symptom Patterns in Depression, in Handbook ofDepression: Treatment, Assessment and Research, E. E. Beckham and W. R. Leber (eds.), Dorsey Press, Homewood, Illinois, pp. 372-407,1985. 12. J. A. Yesavage, T. L. Brink, T. L. Rose, and M. Adey, The Geriatric Depression Rating Scale: Comparison with Other Self-report and Psychiatric Rating Scales, inAssessment in Geriatric Psychopharmacology, T. Crook, S. Ferris, and R. Bartus (eds.), Mark Powley Associates, New Canaan, Connecticut, pp. 153-167,1983. 13. W. M. Petrie, Psychiatric Rating Scales for Inpatient Research, in Assessment in Geriatric Psychopharmacology, T. Crook, S. Ferris, and R. Bartus (eds.), Mark Powley Associates, New Canaan, Connecticut, pp. 59-68,1983. 14. R. L. Spitzer, J. Endicott, and E. Robins, Research Diagnostic Criteria: Rationale and Reliability, Archives of General Psychiatry, 36, pp. 773-782,1978. 15. A. Raskin, Partialling out the Effects of Depression and Age on Cognitive Functions: Experimental Data and Methodologic Issues, in Handbook of Clinical Memory Assessment of Older Adults, L. W. Poon, T. Crook, K. L. Davis, C. Eisdorfer, B. J. Gurland, A. W. Kaszniak, and L. W. Thompson (eds.), American Psychological Association, Washington, D.C., 1986. 16. C. M. Kelley, Depressive Mood Effects on Memory and Attention, in Handbook of Clinical Memory Assessment of Older Adults, L. W. Poon, T. Crook, K. L. Davis,
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C. Eisdorfer, B. J. Gurland, A. W. Kaszniak, and L. W. Thompson (eds.), American Psychological Association, Washington, D.C., pp. 238-243,1986. 17. €1. L. Kahn, A. I. Goldfarb, M. Pollack, and A. Peck, Brief Objective Measures for the Determination of Mental Status in the Aged, American Journal of Psychiatry, 117, pp. 326-328,1960. 18. A. T. Beck and R. W. Beck, Screening Depressed Patients in Family Practices: A Rapid Technique, Postgraduate Medicine, 52, pp. 81-85,1972.
Direct reprint requests to: Forrest Scogin Department of Psychology University of Alabama Tuscaloosa. AL 35487-0348
DEVELOPMENT OF AN INTERVIEW-BASED GERIATRIC DEPRESSION RATING SCALE
CHRISTINEJAMISON FORREST SCOGIN University of Alabama, Tuscaloosa
ABSTRACT
The geriatric depression rating scale (GDRS) is a new interview-based depression rating scale designed for use with adults 60 years of age or older. The scale was developed to fill a need for an instrument that would be sensitive to the problems encountered in assessing depression among older adults. The GDRS was designed by using items from the self-report Geriatric Depression Scale (GDS) as topic areas in a structured clinical interview similar to that of the Hamilton Rating Scale for Depression (HRSD). The 35-item rating scale was administered to 68 older individuals with a range of affective disturbance. The scale was found to have internal consistency and split-half reliability comparable to the HRSD and GDS. Concurrent validity, construct validity, external criterion validity, sensitivity, and specificity were all found to be acceptable.
Older adults are exposed to many stressors such as loss of relatives and friends through death, through mandatory retirement, declining physical health, and poorer cognitive functioning. Depression can follow these losses. Surveys have indicated that depression is a common problem among older adults with approximately two to seven percent of the older adult population being clinically depressed [l,21. The diagnosis of depression among older adults is often difficult. Many older adults have physical problems which confound somatic indicators of depression such as sleep problems, weight loss, fatigue, and irritability [3]. Further complicating the diagnosis are complaints about memory losses, 193 0 1992, Baywood Publishing Co., Inc.
doi: 10.2190/0803-3FBC-6EB0-ACH4 http://baywood.com
194 / JAMISON AND SCOGIN
confusion, and inability to concentrate. These symptoms make differentiation between depression and the early stages of dementias difficult [4]. Further complicating the picture, the early stages of dementia are often accompanied by depression as patients become aware of cognitive losses. These concerns prompted the development of the Cornell Scale for Depression in Dementia [ 5 ] , an instrument designed for assessing depression severity in patients evidencing irreversible or reversible dementia. However, the reliance on collateral sources of information make it less attractive for use with most communitydwelling older adults. One of the widely used interview schedules for depression research is the Hamilton Rating Scale for Depression [6]. The popularity of the HRSD is attributed to its brevity in administration (30 minutes), its agreement in ratings among clinicians [7], and its sensitivity to change in depressive severity [8, 91. However, the HRSD has several disadvantages such as less than specific rating guidelines [lo, 111 and heavy reliance on somatic indicators of depression [4, 8, 91. Yesavage, Brink, Rose, and Adey [12] also note the need for geriatric depression scales. They observe that the HRSD is a widely accepted instrument, but one not originally designed for use with older adults and lacking in validation with this group. Petrie [13] recommends that the HRSD be used “very prudently” with older patients. The HRSD’s heavy loading of somatic items presents, in particular, a problem when assessing older adults [4, 81. Gallagher and Thompson [4] describe the difficulty in discriminating between physical complaints due to health related problems and those due to depression when using the HRSD. They comment that the difficulty derives from artificially high HRSD scores for older adults unless the interviewer uses additional information concerning the individuals’ health status to modify HRSD scores [4]. Gallagher [8] concludes her review of the HRSD by commenting that “our research group cannot heartily recommend the HRSD . . . ” (pg. 210). The Geriatric Depression Rating Scale (GDRS) was developed to fill the need for a rating scale which is sensitive to the special problems encountered in assessing depression in older adults. More specifically, we were interested in developing a brief, yet thorough scale to assess depression in older adults. The GDRS was modeled after an already popular self-rating Geriatric Depression Scale [GDS, 31. Further, our research plan called for validation of the instrument with a heterogeneous crosssection of older adults, adding to the generalizability of the instrument. Finally, we planned to provide a detailed instruction manual for raters, providing for potentially greater concordance between raters across research settings. Although the GDRS includes somatic items to conform to Research Diagnostic Criteria [RDC; 141, the instrument does not rely on them heavily and specifications for rating the somatic items are detailed in the manual. In addition, the GDRS includes cognitive items such as memory problems, difficulty in concentration, and mental clarity which are thought to be linked to depression in older adults [15, 161.
GERIATRIC DEPRESSION / 195
METHOD
Item Developmentand Instruments Used Two depression instruments which are in current use are the Hamilton Rating Scale for Depression [HRSD; 61 and the Geriatric Depression Scale [GDS; 31. The HRSD was developed to quantify interviews so that treatment progress and outcome could be assessed once a person was diagnosed as depressed. The clinician rates depression using an interview format, and thus, the HRSD possesses the capacity to assess people who cannot answer a self-report measure due to severity of illness or inability to read [6]. The GDS [3] is a self-report measure of depression that was designed as a screening device specifically for use with older adults. The final version includes 30 items (out of 100 original items) which correlate with symptoms of depression. Somatic items were excluded as they did not correlate with depressive symptoms [3]. The GDRS, a 35-item instrument, was designed as a research tool to assess the effects of treatment for depression in older adults. Twenty-nine of the items on the GDRS were developed by using the 30 items on the GDS as topic areas for discussion in an interview. Among the items included are life satisfaction, relative well-being, participation in activities and interests, morning mood, ability to concentrate, and hopefulness. Ratings are made on a 0-4 scale with higher scores indicating greater severity. Six somatic items were added to conform to Research Diagnostic Criteria [14]. They are early, middle, and late insomnia; weight loss, changes in appetite, and somatic anxiety symptoms. A detailed manual was developed to instruct and guide the interviewer in reliable scoring of the 35 items. Scores on the GDRS can range from 0 to 132. A summary of the content areas covered in the HRSD, GDS, and GDRS is presented in Table 1.
Sample Description The sample consisted of 19 older adults solicited from the community, 24 individuals from a depression treatment study, and 25 individuals who were referred for depression assessment from a VA hospital. These groups were chosen to represent a cross-section of older adults likely to be assessed for depression. The criterion for participation in the study was that participants must be aged 60 or older, although there was one participant aged 58. Table 2 contains demographic characteristics of the sample. In addition to the demographic information, a mental status quotient and a health status rating were obtained for each participant. The mental status quotient was obtained using the Mental Status Questionnaire [17]. On a scale from 0 (not oriented) to 10 (fully oriented), the mean score for the sample was 8.96 (SO = 1.61). To obtain a health status rating, participants were asked to self-rate their health status on a scale of 0 @oar health)
196 I JAMISON AND SCOGIN
Table 1. Content of Items Comprising the HRSD, GDS, and GDRS
HRSDB
GDS~
GDRS'
1. Depressed mood 2. Feelings of guilt 3. Suicide 4. Insomnia early 5. Insomnia middle 6. Insomnia late 7. Work and activities 8. Psychomotor retardation 9. Agitation 10. Anxiety psychic 11. Anxiety somatic 12. Appetite 13. Fatiguability 14. Genital symptoms 15. Hypochondriasis 16. Loss of weight 17. Insight 18. Diurnal variation 19. Depersonalization 20. Paranoid symptoms 21. Obsessional and compulsive symptoms 22. 23. 24. 25. 26. 27. 28.
Life satisfaction Activities and interests Empty life Boredom Hopeful 0bsessions Good sprits Catastrophic fear
Good spirits Life satisfaction Exciting life Boredom Relative well-being Activities and interests Initiating projects Insomnia early
Happy Hopeless Restlessness Stay at home Future worry Memory problems Suicidal Blue Worthlessness Past worry Exciting life Initiating projects Energy
Insomnia middle Insomnia late Morning mood Energy level Appetite Loss of weight Stay at home Sociality Decision making Concentration Memory problems Mental clarity Hopefulness
Hopelessness Relative well-being Upset Crying Concentration Morning mood Sociality
29. 30. 31. 32. 33. 34. 35.
Decision making Mental clarity
Future worry Catastrophic fear Obsessions Upset Anxiety somatic Restless Psychomotor retardation Past worry Worthlessness Emptiness Blue Crying Hopelessness Suicidal
GERIATRIC DEPRESSION / 197
Table 2. Demographic Characteristics of Sample Variable Age Years of Education Annual Income in thousands Sex Male Female Race White Black Marital Status Married Widowed Divorced Single
M
SD
70.91 13.19 17.00
6.30 3.22 12.03
n
%
33 35
48 52
61 7
90
38 17 9 4
56 25 13 6
10
to 10 (excellent health). The mean score on the health status rating for the sample was 5.86 (So= 2.27).
Procedure Participants were interviewed at an outpatient mental health facility (except for participants from the VA Hospital who were interviewed at the hospital). Interviews were conducted in therapy rooms in the clinic or in an office at the hospital. Participants were briefly screened for mental status by the interviewer using the Mental Status Questionnaire and were asked to self-rate their health status. They were then given two interview format measures, the HRSD and GDRS, and two self-report measures, the Beck Depression Inventory-short form [ 181 and the GDS. The interviews for depression using the GDRS and the HRSD were conducted first and were alternated as to which was administered first. Immediately following the interviews the participants were given the self-report measures in alternating order. All HRSD and GRSD interviews were conducted by an advanced clinical psychology graduate student after supervised training. GDRS interviews averaged approximately 35 minutes, whereas HRSD interviews lasted approximately 30 minutes on average. The self-report instruments were also distributed by the interviewer. To insure reliability, a random selection of
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interviews were audio-taped and then were rated by an experienced clinical psychologist. The average percent agreement across items was 86 percent for the GDRS and 80 percent for the HRSD.
RESULTS Item Selection Items were selected on the basis of corrected item to total correlations and the squared multiple correlation coefficients. Using the corrected item to total correlation, six items, item numbers 8, 14, 17, 19, 25, and 31, did not correlate highly with the total score (their item to total correlations were less than .4). These items’ domains were early insomnia, weight loss, difficulty in decision making, memory problems, getting upset over little things, and feelings that life is empty. However, the six items were included because their squared multiple correlations coefficients ranged from 51 to .68 which was well within the acceptable range. Furthermore, when the squared multiple correlation coefficient from a regression model with all 35 items were examined, the instrument was able to explain at least 72 percent of the variability in the depression measure. Therefore, on the basis of these two techniques, all 35 items were retained. Table 3 contains sample items, suggested interviewer questions, and the corresponding rating scale. Reliability Internal consistency was assessed using Cronbach’s alpha coefficient and an alpha coefficient of .92 was obtained. Comparable values for the HRSD and GDS are .90 and .94, respectively [3].The mean inter-item correlation was .24 with a range of 3 6 . The HRSD and GDS have mean inter-item correlations of 3 4 and 3 6 , respectively [3].Split-half reliability for the GDRS was assessed using the Spearman-Brown formula and a coefficient of .89 was obtained. Split-half reliability coefficients for the HRSD and GDS arc .82 and .94, respectively [3 ]. Table 4 presents these internal consistency comparisons. Concurrent Validity The Pearson correlation coefficient was used to assess concurrent validity with the HRSD, BDI and GDS. These coefficients, presented in Table 5, were .83, .69 and .8Srespectively, and all were significant at the .01 level. Discriminate Validity Participants were divided into two groups, depressed and nondepressed, based on their HRSD scores using a cutoff score of 11+as depressed [3 ].The HRSD was chosen as the criterion measure due to its widespread acceptance and use as a
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Table 3. Sample Items From the GDRS LIFE SATISFACTION How do you feel about your life? Do you feel you have a good life? Are you basically satisfied with your life? Overall do you find life rewarding? If you could do it over again, would you change anything? 0 = Indicates no dissatisfactionwith life. 1 = Indicates sometimes feeling dissatisfied with life. 2 = Indicates often feeling dissatisfied with life. 3 = Indicates feeling dissatisfied with life most of the time and this interferes with functioning. 4 = Always feels dissatisfied with life.
DECISION MAKING How do you feel about making decisions? Is it easy for you to make decisions? What kinds of decisions are easy for you to make? 0 = Almost always easy to make decisions. 1 = Some difficulty in making decisions. Little or no difficulty in daily functioning. 2 = Seldom easy to make decisions, and this interferes with daily functioning. 3 = Significant problems in functioning due to decision-making difficulties. 4 = Cannot make decisions. Interferes severely with functioning in all areas.
HOPELESSNESS Do you feel hopeless? Is your situation hopeless?
0 = Almost never feels hopeless. 1 = Seldom feels hopeless. 2 = Sometimes feels hopeless. 3 = Often feels hopeless and this interferes with functioning. 4 = Feels hopeless most of the time and this severely affects most areas of functioning.
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Table 4. Comparisons of Internal Consistency Measures for the GDRS, HRSD, and GDS Index
GDRS~
Mean interim correlation Alpha coefficient Split-half reliability
0.24 0.92 0.89
H R S ~
0.34 0.90 0.82
GDS~
0.36 0.94 0.94
Note: The data in columns 2 and 3 are from "Development and validation of a geriatric depression screening scale: A preliminary report" by J. A. Yesavage, T. L. Brink, T. L. Rose, 0. Lum, V. Huang, M. Adey, and V. 0. Leirer, 1983,Journal of Psychiatric Research, 17, p. 43.Copyright 1983 by Pergamon Press Ltd. Adapted by permission. 'Geriatric Depression Rating Scale bHarnilton Rating Scale for Depression 'Geriatric Depression Scale
Table 5. Pearson Correlation Coefficientsfor HRSD, BDI, GDS, and GDRS
HRSD BDI GDS GDRS
2 < ."'
1.oo
.65* .72* .83*
1.oo
.67* .69*
1.oo .85*
1.oo
Hamilton Rating Scale for Depression bBeck Depression Inventory 'Geriatric Depression Scale dGeriatric Depression Rating Scale
measure of depression. A discriminant function analysis was used to determine if the GDRS discriminated well between depressed and nondepressed participants. The results showed that the GDRS did discriminate between the two groups at the .01 level of significance. Group means and standard deviations are presentcd in Table 6.
Sensitivity and Specificity An important aspect in the development of a depression instrument is determining a cutoff score. There is a tradeoff between sensitivity (correctly identifying depressed people by their scores being equal to or greater than the cutoff score) and specificity (correctly identifying nondepressed people by their scores
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being below the cutoff point). A low cutoff score would increase the sensitivity but decrease the specificity. A high cutoff score would decrease the sensitivity but would increase the specificity. Table 7 indicates sensitivity and specificity percents for the various cutoff scores for the GDRS, the HRSD, and the GDS. Participants were divided into two groups (depressed and nondepressed) using a cutoff score of 20+ on the GDRS. This cutoff score yields 88 percent sensitivity and 82 percent specificity. The mean score for the depressed group was 38.64 and
Table 6. Means and Standard Deviations for the Depression Rating Scales as a Function of Classification Classification Rating Scale
Depressed (n = 34)
Nondepressed (n = 34)
37.97 16.14
14.97 8.81
14.97 4.00
5.82 3.05
GDRSa M SD HRSD~ M SD
'Geriatric Depression Rating Scale bHamilton Rating Scale for Depression
Table 7. Cutoff Scores for Sensitivity and Specificity on the GDRS, HRSD, and GDS Criterion Cutoff Scores Sensitivity Specificity
GDRS'
18+ 20+ 22+ 94% 88% 82% 68% 82% 88%
HRSD~
9+ 1 1 + 13+ 88% 86% 73% 75% 80% 85%
GDS~
9+ 11+ 14+ 90% 84% 80% 80% 95% 100%
Note: The data in columns 4 through 9 are from "Screeningtests for geriatric depression" by T. L. Brink, J. A. Yesavage, 0 Lum, P. H. Heersema, M. Adey, and T. L. Rose, 1982, Clinical Gerontologist, 1, p. 42. Copyright 1982 by The Haworth Press, Inc. Adapted by permission. aGeriatric Depression Rating Scale *Hamilton Rating Scale for Depression 'Geriatric Depression Scale
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the mean score for the nondepressed group was 12.78. A 1-test was performed between the two groups and the results indicated statistically significant differentiation between the groups, t(66) = -9.20,~< .001.
DISCUSSION The results of this investigation indicate that the GDRS has adequate reliability and validity in the measurement of depression in older adults. The GDRS compares favorably with the most popular interview-based measure of depression, the HRSD. Specifically, our results suggest that the GDRS possesses adequate internal reliability, concurrent validity, construct validity, and external criterion validity. Our results do not allow us to claim superiority for the GDRS over the more traditional HRSD. Based solely on psychometric data, the two scales are quite comparable. In fact, in bootstrapping research of this sort, agreement with the traditionally used scale is necessary for validation. However, we suggest that the GDRS has at least two relative advantages over the HRSD. One is that the questions were developed specifically in reference to older adults, more precisely, they build upon the work of Yesavage and colleagues with the GDS. Secondly, we feel that the GDRS will require less rater training and less discretionary decisionmaking on the part of the rater. With these probable advantages, we believe that clinicians and researchers will find the GDRS advantageous to the HRSD. Given the early stage of development of the GDRS, we encourage clinicians and researchers to collect reliability and validity data to aid in validation efforts. Specifically, future research should be directed towards establishing the temporal stability of GDRS ratings through test-retest measures and sensitivity to change exhibited by the scale in longitudinal research. The interviewer reliability achieved by raters not affiliated with the development of the scale is also desirable. The generalizability of the scale would be enhanced by studies of subgroups such as those experiencing physical aliments or elders suffering mild to moderate cognitive impairment. Given the present characteristics of the GDRS, the instrument is appropriate for use in clinical research involving the assessment of depression in older adults.
ACKNOWLEDGMENTS We gratefully acknowledge the assistance of Charles Ward and Kimberly Gochneaur.
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2. B. J. Gurland, The Comparative Frequency of Depression in Various Adult Age Groups, Journal of Gerontology, 31, pp. 283-292,1976. 3. J. A. Yesavage, T. L. Brink, T. L. Rose, 0. Lum, V. Huang, M. Adey, and V. 0.hirer, Development and Validation of a Geriatric Depression Screening Scale: A Preliminary Report, Journal of Psychiatric Research, 17, pp. 37-49,1983. 4. D. Gallagher and L. W. Thompson, Depression, in Clinical Geropsychology: New Directions in Assessment and Treatment, P. M. Lewinsohn and L. Teri (eds.), Pergamon Press, New York, pp. 7-37,1983. 5. G. S. Alexopoulos, R. C. Abrams, R. C. Young, and C. A. Shamoian, Cornell Scale for Depression in Dementia, Biological Psychiatry, 23, pp. 271-284,1988. 6. M. Hamilton, A Rating Scale for Depression, Journal OfNeurology, Neurosurgery and Psychiatry, 23, pp. 56-62,1960. 7. J. L. Hedlund and B. W. Vieweg, The Hamilton Rating Scale for Depression: A Comprehensive Review, Journal of Operational Psychiatry, 11, pp. 48-65, 1979. 8. D. Gallagher, Assessment of Depression by Interview Methods and Psychiatric Rating Scales, in Handbook of Clinical Memory Assessment of Older Adults, L. W. Poon, T. Crook, K. L. Davis, C. Eisdorfer, B. J. Gurland, A. W. Kaszniak, and L. W. Thompson (eds.), American Psychological Association, Washington, D.C., pp. 202-212,1986. 9. J. G. Rabkin and D. F. Klein, The Clinical Measurement of Depressive Disorders, in The Measurement of Depression, A. J. Marsella, R. M. A. Hirschfeld, and M. M. Katz (eds.), Guilford Press, New York, pp. 30-83,1987. 10. I. W. Miller, S. Bishop, W. H. Noman, and H. Maddever, The Modified Hamilton Rating Scale for Depression: Reliability and Validity, Psychiatry Research, 14, pp. 131-142, 1985. 11. B. F. Shaw, T. M. Vallis, and S. B. McCabe, The Assessment of the Severity and Symptom Patterns in Depression, in Handbook ofDepression: Treatment, Assessment and Research, E. E. Beckham and W. R. Leber (eds.), Dorsey Press, Homewood, Illinois, pp. 372-407,1985. 12. J. A. Yesavage, T. L. Brink, T. L. Rose, and M. Adey, The Geriatric Depression Rating Scale: Comparison with Other Self-report and Psychiatric Rating Scales, inAssessment in Geriatric Psychopharmacology, T. Crook, S. Ferris, and R. Bartus (eds.), Mark Powley Associates, New Canaan, Connecticut, pp. 153-167,1983. 13. W. M. Petrie, Psychiatric Rating Scales for Inpatient Research, in Assessment in Geriatric Psychopharmacology, T. Crook, S. Ferris, and R. Bartus (eds.), Mark Powley Associates, New Canaan, Connecticut, pp. 59-68,1983. 14. R. L. Spitzer, J. Endicott, and E. Robins, Research Diagnostic Criteria: Rationale and Reliability, Archives of General Psychiatry, 36, pp. 773-782,1978. 15. A. Raskin, Partialling out the Effects of Depression and Age on Cognitive Functions: Experimental Data and Methodologic Issues, in Handbook of Clinical Memory Assessment of Older Adults, L. W. Poon, T. Crook, K. L. Davis, C. Eisdorfer, B. J. Gurland, A. W. Kaszniak, and L. W. Thompson (eds.), American Psychological Association, Washington, D.C., 1986. 16. C. M. Kelley, Depressive Mood Effects on Memory and Attention, in Handbook of Clinical Memory Assessment of Older Adults, L. W. Poon, T. Crook, K. L. Davis,
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C. Eisdorfer, B. J. Gurland, A. W. Kaszniak, and L. W. Thompson (eds.), American Psychological Association, Washington, D.C., pp. 238-243,1986. 17. €1. L. Kahn, A. I. Goldfarb, M. Pollack, and A. Peck, Brief Objective Measures for the Determination of Mental Status in the Aged, American Journal of Psychiatry, 117, pp. 326-328,1960. 18. A. T. Beck and R. W. Beck, Screening Depressed Patients in Family Practices: A Rapid Technique, Postgraduate Medicine, 52, pp. 81-85,1972.
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