The Depression Scale (DEPS) as a case finder for depression in various subgroups of primary care patients

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European Psychiatry 23 (2008) 580e586 http://france.elsevier.com/direct/EURPSY/

Original article

The Depression Scale (DEPS) as a case finder for depression in various subgroups of primary care patients Outi Poutanen a,*, Anna-Maija Koivisto b, Raimo K.R. Salokangas c a

University of Tampere, Medical School/Tampere University Hospital, Psychiatric Clinic, P.O. Box 607, Teiskontie 35, Tampere 33014, Finland b University of Tampere, School of Public Health, Finland c University of Turku, Department of Psychiatry/University Central Hospital in Turku, Psychiatric Clinic, Finland Received 16 April 2008; received in revised form 19 June 2008; accepted 20 June 2008 Available online 7 September 2008

Abstract Purpose. e The quick and simple Depression Scale (DEPS) has been a popular self-rating depression scale in Finland for nearly 15 years. The purpose was to assess the validity of the DEPS in various subgroups of patients. Materials and methods. e Primary care patients, aged 18e64, completed a postal questionnaire including the DEPS. Of the 1643 patients all screen-positive subjects and every 10th screen-negative subject were invited for interview (the Present State Examination, PSE). Complete DEPS scores were available for 410 patients. They were grouped by gender, age, marital status, perceived physical health, basic education and the Michigan Alcoholism Screening Test (MAST) score. Separately for each subgroup, receiver operating characteristic (ROC) curve analyses were done, sensitivity, specificity, area under the curve (AUC), predictive values and likelihood ratios were calculated, and Cronbach’s a was estimated. Results. e The DEPS was valid in general, but best for patients with basic education longer than 9 years. Discussion. e The key statistical figures for the DEPS were comparable to the figures for other short self-rating scales. Conclusion. e The DEPS is a valid case finder for primary care patients in the age group 18e64 years, and especially suitable for more highly educated patients. Future studies comparing the DEPS with other simple depression rating scales are needed. Ó 2008 Elsevier Masson SAS. All rights reserved. Keywords: Depression; Primary health care; Questionnaire; Subgroup analyses

1. Introduction Major depression has been predicted to be one of the leading causes of disability-adjusted life years in the next years [26]. Valid and simple methods for screening and recognizing depression are needed. There are numerous scales for screening or assessing depression [18,17]. Most of them have been developed with psychiatric patients, but nowadays they are useful for both primary care and psychiatric patients. However, not every scale is suitable for every group of patients. Age and gender are at

* Corresponding author. Tel.: þ358 50 3068159. E-mail address: [email protected] (O. Poutanen). 0924-9338/$ - see front matter Ó 2008 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.eurpsy.2008.06.007

least important background factors to be taken into account [27,19]. Specific scales and inquiries have been elaborated for different subpopulations of patients. There are instruments for children [36], for adolescents [31], for newly delivered mothers [12], and for geriatric patients [48]. The Edinburgh Postnatal Rating Scale, EPDS, [12] has been used not only for newly delivered mothers but for expecting fathers [24], and for menopausal women, too [5]. The EPDS is an example of a depression scale that takes into account the fact that somatic symptoms may lead to false positive results of depression. The Beck Depression Inventory (BDI) [8] is one of the most widely used self-rating depression questionnaires. It has been revised [7], and there is also a short form of the questionnaire (BDI-SF) comprising the cognitive-affective items of it. The BDI-SF has been recommended for assessing depression in the

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medically ill [6]. The figures for sensitivity and specificity have been high in some studies [3,16]. The popular Hospital Anxiety and Depression Scale, HADS [50], is a 14-item self-report screening scale that was originally developed to detect the possible presence of anxiety and depressive states in the setting of a medical outpatient clinic. It contains two seven-item scales: one for anxiety and one for depression. According to a review of the validation of the HADS [9] the sensitivity and specificity for the depression subscale HADS-D in all kinds of patients is approximately 80%, the area under the curve (AUC) between 0.84 and 0.96, and Cronbach’s a between 0.67 and 0.90. When three brief self-rating scales (the WHO-5 Well Being Index, the 12-item General Health Questionnaire, GHQ-12, and the Brief Patient Health Questionnaire, B-PHQ) were compared with the Composite International Diagnostic Interview (CIDI) telephone interview not in subpopulations but generally in primary care patients, the WHO-5 proved to be the best detector for depression with high sensitivity and high negative predictive value, and the B-PHQ the best to make a diagnosis with high specificity and high positive predictive value [20]. When subpopulations were assessed, the sensitivity of WHO-5 was lower for male patients and for minor depression [19]. There are some studies based on the large American epidemiological catchment area study e ECA e that have observed detection of depression with different self-report instruments and have taken into consideration the sociodemographic background of patients. Older age, male sex, and having less depression-related impairment were associated with under-detection by the self-report Diagnostic Interview Schedule (DIS). Effects of education and co-morbidity were small and not significant [14]. In another study subjects diagnosed only by one lay-administered interview (the DPAX) tended to have less education than those diagnosed only by another lay-administered interview (the DIS) [25]. The Depression Scale, DEPS [33], has been in very active clinical use in primary health care in Finland, and it is recommended for this purpose in the Finnish Evidence-Based Treatment Guideline for Depression [43]. The DEPS has indicated gender neutrality in some depression studies [35] and seems to have some predictive validity [28,29]. The DEPS may help general practitioners to detect depression among suicide attempters, but it should not be used to exclude depression [44]. It also appears to be useful for screening depression among schizophrenic patients [21]. The DEPS was based on a screening instrument developed by Barrett et al. [4], and supplemented by a question on insomnia. It has been validated with primary care patients but the validity of the DEPS for various subpopulations of primary care patients has not yet been assessed. The aim of this study was to assess the case finding ability of the DEPS in different subgroups of primary care patients paying attention to gender, age, marital status, perceived physical health, basic education, and possible problems with alcohol. According to the findings from earlier studies we expected age and possibly education to be significant background factors.

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2. Method 2.1. Design and participants This study forms part of the more extensive Tampere Depression Project [32e34]. The study was carried out between September 1991 and May 1992 with primary care patients in the Tampere Region (Finland). The study group consisted of 2487 individuals randomly selected from among patients aged between 18 and 64 who had visited community health centres. The only exclusion criteria were age <18 or >64 years or wrong place of residence. In all, 1643 patients (66.1%) completed and returned the questionnaire including questions on patient’s demography, health, functioning, as well as the DEPS [33,34], and the Michigan Alcoholism Screening Test (MAST) [37]. Among the drop-outs, male, young, single, and patients who had used emergency services were over-represented. However, there was no statistically significant difference between the responders and the non-responders in the GP’s assessment of depressive symptoms during the consultation. Of the 1643 primary care patients who returned the screening questionnaire, all screenpositive subjects (n ¼ 372) and every 10th screen-negative subject (127 out of 1271 individuals) were invited for interview. Screen-positive signified DEPS sum score >8, and screen negative 8. In order to evaluate the effect of dropping out at this phase of the study, the background characteristics of the patients completing the DEPS and the interview were compared with those of the patients who refused to participate in the interview (n ¼ 53) or those whose DEPS score was incomplete (n ¼ 26). Background characteristics (gender, age, marital status, basic education) did not significantly differ between the groups. Among those drop-outs who adequately completed the DEPS and the patients completing both the DEPS and the interview, the DEPS score results did not differ between the groups. 2.2. Study procedure The DEPS includes 10 items and four response alternatives scoring 0e3 (Table 1). A total of 436 subjects were interviewed (319 screen positive and 117 screen negative). Complete DEPS score was available for analyses in 410 patients. To diagnose clinical depression, the Present State Examination (PSE, 9th version based on the criteria of the ICD-8) and the CATEGO computer program [46] were used. Their PSE diagnoses were as follows: severe depression n ¼ 60, mild depression n ¼ 51, depressive symptoms n ¼ 57, other psychiatric symptoms n ¼ 167, other psychiatric diagnosis n ¼ 28, no psychiatric symptoms n ¼ 47. The questions about the occurrence of symptoms of clinical depression referred to those experienced during the previous month. The researchers were one psychiatrist, two psychologists, one social psychologist and one medical student. They were blind to the DEPS screening results. They had all received thorough official training in the use of the PSE. The study protocol was approved by the Tampere University Hospital Ethics Committee and written informed consent was obtained.

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Table 1 The DEPS,a below is a list of statements concerning you e please circle one of the numbers to the right that best describes your mood during the past month

Analyses were done using SPSS for Windows version 13.0 statistical software [42] and AUC values were tested using Stata statistical software, version 9 [47] (www.stata.com). p Values smaller than 0.05 were considered statistically significant.

During the last month I have

Not at all

A little

Quite a lot

Extremely

1. Suffered from insomnia 2. Felt blue 3. Felt everything was an effort 4. Felt low in energy or slowed down 5. Felt lonely 6. Felt hopeless about the future 7. Not got any fun of life 8. Had feelings of worthlessness 9. Felt all pleasure and joy has gone from life 10. Felt that I cannot shake off the blues even with help from family and friends

0 0 0

1 1 1

2 2 2

3 3 3

3. Results

0

1

2

3

3.1. Cronbach’s a

0 0 0 0 0

1 1 1 1 1

2 2 2 2 2

3 3 3 3 3

0

1

2

3

Cronbach’s a reflecting the internal consistency of the screening scale was between 0.85 and 0.90. The a values were good in each subgroup but best in the subgroups 18e29 years of age, 30e39 years of age, men, and good perceived health (Table 2). 3.2. Area under the curve

a

First published (without the introduction) in Acta Psychiatrica Scandinavica 1995 July;92(1):10e6.

2.3. Statistical procedure Patients were grouped by gender, age, basic education, marital status, (self-perceived) physical health, and MAST score. The validity of the DEPS was evaluated against the PSE diagnosis of depression which comprised PSE diagnoses severe depression and mild depression using Receiver Operating Characteristic (ROC) curve analyses. Analyses were done for all patients and separately for each subgroup. Sensitivity and specificity at DEPS score cut-off point >11, positive and negative predictive values (PPV, NPV), positive and negative likelihood ratios (LRþ, LR), AUC, and Cronbach’s a were calculated and compared. Sensitivity is the proportion of true positives that are correctly identified by the test. Specificity is the proportion of true negatives that are correctly identified by the test [1]. Positive predictive value is the proportion of patients with positive test results who are correctly diagnosed. Negative predictive value is the proportion of patients with negative test results who are correctly diagnosed [2]. Likelihood ratio summarizes how many times more (or less) likely patients with the disease are to have that particular result than patients without the disease. When tests report results as being either positive or negative the two likelihood ratios are called the positive likelihood ratio and the negative likelihood ratio [13]. For analyses, age was divided into four categories: 18e29 years, 30e39 years, 40e49 years, and 50e64 years. Basic education was dichotomized as follows: 9 years of basic education, or >9 years of basic education. Marital status was divided into two categories: married/cohabiting, or other. Perceived physical health was dichotomized: good ¼ very good/good, and poor ¼ average/rather poor/or poor. MAST was dichotomized using 3/4 as a cut-off. The higher than usual cutoff point [22] was based on Finnish drinking habits [38,39]. The PSE was dichotomized as follows: classes 1e2 ¼ clinical depression, and classes 3e7 ¼ no clinical depression.

In the ROC analysis for all patients the AUC was 0.79. When the subgroups were analyzed separately, the AUC was largest in those whose basic education was >9 years, second largest in the youngest subgroup, and third largest in men. The AUC was lowest in those whose MAST score was >3, second lowest in the subgroup 40e49 years of age, and third lowest in those with basic education 9 years. The difference in AUCs between the groups was significant ( p ¼ 0.01) only in the subgroups defined by basic education (Table 2, Fig. 1). 3.3. Sensitivity and specificity, predictive values and likelihood ratios In the ROC analysis for all patients the ideal cut-off point (ideal balance of sensitivity and specificity) was 11/12 with a sensitivity of 74.8% and a specificity of 68.9%. With different cut-off points sensitivity and specificity were correspondingly: 10/11 e 82.0% and 58.5%, 9/10 e 91.9% and 48.5%, 8/9 e 97.3% and 34.8%, and 12/13 e 63.1% and 75.9%. The figures for the sensitivity and specificity at cut-off point 11/12 for various subgroups can be seen in Table 2. Predictive values and likelihood ratios in all patients and in various subgroups at the cut-off level of 11/12 are also presented in Table 2. The best values for specificity, PPV, LRþ, and LR were in the subgroup with basic education >9 years (LR also in the age group 18e29 years). Values for sensitivity and NPV were best in the youngest age group 18e29 years. Values for specificity, NPV, LRþ, and LR were poorest in the subgroup with MAST score >3. Values for sensitivity and PPV were poorest in the subgroup with physical health perceived to be poor. 4. Discussion 4.1. Principal findings The DEPS was valid in general for both men and women. The validity of the DEPS was best for patients with a basic

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Table 2 Sensitivity, specificity, area under the curve (AUC), predictive values, and Cronbach’s a of the Depression Scale (DEPS) in various subgroups of patients Subgroups of patients

Descriptive statistics of receiver operating characteristic (ROC) curves, predictive values and Cronbach’s a n

Sensitivitya

Specificitya

AUCb

PPV

NPV

LRþ

LR

Cronbach’s a

All patients

410

74.8

68.9

0.79

47.2

88.0

2.40

0.37

0.87

Gender Men Women

127 283

83.3 71.6

62.9 71.8

0.83 0.79

41.0 50.4

92.4 86.3

2.25 2.54

0.27 0.40

0.89 0.85

Age 18e29 30e39 40e49 50e64

years years years years

64 78 101 167

84.6 77.8 72.5 72.5

74.5 70.0 65.6 67.7

0.85 0.81 0.76 0.79

45.8 43.8 58.0 41.4

95.0 91.3 78.4 88.7

3.32 2.59 2.11 2.25

0.21 0.32 0.42 0.41

0.90 0.89 0.85 0.86

Basic education 9 years >9 years

339 70

72.7 82.6

66.5 83.0

0.77 0.89

43.2 70.4

87.4 90.7

2.17 4.85

0.41 0.21

0.87 0.86

Perceived physical health Good Bad

135 274

63.6 77.5

77.9 63.2

0.79 0.78

35.9 50.4

91.7 85.4

2.88 2.11

0.47 0.36

0.89 0.85

MAST score 3 >3

334 59

73.8 73.9

70.4 52.8

0.79 0.75

46.0 50.0

88.9 76.0

2.50 1.57

0.37 0.49

0.86 0.87

Marital status Married or cohabiting All others

262 148

74.1 75.5

72.1 62.1

0.79 0.78

43.0 52.6

90.7 81.9

2.65 1.99

0.36 0.40

0.87 0.86

a b

Sensitivity and specificity at cut-off level 11/12. AUC, area under the curve in receiver operating characteristic curve (ROC) analysis.

education longer than 9 years. The DEPS did not work well with patients with MAST score over 3. 4.2. ROC analyses and the internal consistency of the DEPS The ideal balance of sensitivity and specificity for the whole data was attained with a cut-off point 11/12. For screening purposes in general e implying high sensitivity e a lower cut-off point could be more suitable. The cut-off level used in the screening of this study sample e 8/9 e meant a high sensitivity of 97.3% but specificity under 35%. For screening purposes this kind of balance between sensitivity and specificity is quite acceptable [16]. The DEPS functioned well with the patients in the younger age groups and especially with the more educated patients: both sensitivity and specificity were high, the AUC was large, and the predictive values and likelihood ratios were good. There are studies in which the effects of education on screening are not significant [14], and others in which two self-rating scales were compared and functioned in a different way regarding education [25]. There are other questionnaires, for instance the WHO-5 and the B-PHQ, that are gender neutral and good for younger patients [27,19]. The DEPS seems to work in a similar way in this regard. The role of marital status was not important for the validity of the DEPS. Although sensitivity was low for those who perceived their physical health good the AUC was large. Low specificity at the cut-off point 11/12 was a problem for the age group of 40e49

years, for those who perceived their physical health to be poor, for men, and especially for those whose MAST score was >3. Raising the cut-off point would improve specificity. For men a reasonable cut-off point of 12/13 would mean both good sensitivity (76.7%) and better specificity (72.2%). A higher cut-off point of 12/13 for those patients who may have had problems with alcohol would mean sensitivity of 69.6% and specificity of 63.9%, the corresponding figures for cut-off point 13/14 being 65.5% and 77.8%. Scales and questionnaires differ in their ability to recognize depression in people who have problems with alcohol [45,49]. It is usually simpler to use both a depression questionnaire and a questionnaire for drinking habits during the same appointment [10,11]. The PSE is based on symptoms and not on syndromes. The PSE is perhaps not the best gold standard for identifying a combination depression and problems with alcohol. The DEPS is based on short descriptive sentences with a cognitive component. It is possible that the DEPS actually meets better this kind of combination of clinical problems. The LRs were especially poor for patients whose MAST score was >3. On the basis of this study we are not able to say that the DEPS is a valid method for patients who probably have problems with alcohol. Earlier validation studies with instruments screening or diagnosing depression [19,7,3,16,9,25], however, have usually ignored possible drinking problems. This matter deserves further research. Cronbach’s a measures how well a set of items measures a single unidimensional latent construct. It is a coefficient of consistency. Cronbach’s a was good in all subgroups of

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1.00

B 1.00

All patients, and by gender

0.90

0.90

0.80

0.80

0.70

0.70

Sensitivity

Sensitivity

A

0.60 0.50 0.40

Age

0.60 0.50 0.40 0.30

0.30 all patients

0.20

18-29 years 30-39 years 40-49 years 50-66 years

0.20

women

0.10

0.10

men

0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

1-specificity 1.00

D 1.00

0.90

0.90

0.80

0.80

0.70

0.70

Basic education

Sensitivity

Sensitivity

C

1-specificity

0.60 0.50 0.40

0.60 0.50 0.40 0.30

0.30

0.20

0.20 ≤9 years >9 years

0.10

0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

1-specificity

1-specificity

F

MAST score 1.00

Marital status 1.00

0.90

0.90

0.80

0.80

0.70

0.70

Sensitivity

Sensitivity

good poor

0.10

0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

E

Perceived physical health

0.60 0.50 0.40

0.60 0.50 0.40 0.30

0.30 0.20

3

0.10

>3

0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

1-specificity

0.20 married unmarried

0.10

0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

1-specificity

Fig. 1. The receiver operating curves (ROC) in various subgroups of primary care patients.

patients. It was better than in the studies with the HADS-D [9,40]. 4.3. The DEPS and other screening instruments In general the DEPS worked well with various key figures: the results of ROC curve analyses, sensitivity, specificity, AUC, predictive values, likelihood ratios, and Cronbach’s a were quite comparable with the same figures for the HADS-D

[9,40,15,23]. The Dutch version of the HADS has been validated in different groups of general medical outpatients with the same instrument as we used in our study, the Present State Examination (PSE). With all the patients a cut-off score 6/7 yielded the ideal balance of sensitivity (75%) and specificity (68%) and PPV (35%) for the depression subscale. The AUC was 0.82, and Cronbach’s a for GP’s patients in general 0.77 and 0.79 for patients in the age group 18e65. Older age and depressive symptoms showed a small, positive relationship e.g.

O. Poutanen et al. / European Psychiatry 23 (2008) 580e586

elderly subjects with high levels of self-rated depressive symptoms did not fulfil the diagnostic criteria for a depressive disorder [40]. In two primary care studies with DSM-III (and the Clinical Interview Schedule, CIS) as the reference system sensitivity and specificity of HADS-D have been correspondingly 66% and 97% at optimal cut-off level 7/8 [15] and 78% and 91% at optimal cut-off level 6/7 [23]. There are two studies in which the corresponding figures for the BDI-SF are better. In the first study adult medical ward patients were at first interviewed with the Clinical Interview Schedule (CIS) to make ICD-10 psychiatric diagnoses and thereafter on the same day they filled out the BDI-SF. The BDISF showed high sensitivity (100%), specificity (83.1%) and NPV (100%) with a recommended cut-off score 9/10. The AUC was 98.4% [16]. In another study 340 primary care patients while waiting for their appointments with their physicians completed the BDI-II, and the DSM-IV diagnostic criteria were assessed with the Primary Care Evaluation of Mental Disorders (PRIME-MD) Patient Health Questionnaire, PHQ [41], as part of a larger battery of instruments. Following their appointments, patients returned completed questionnaires. The mean BDI-II score was significantly higher for women than for men. The AUC was high 0.96, and the cut-off score 18 yielded the best balance between sensitivity (94%) and specificity (92%). The PPV was 54% and the NPV 99% [3]. However, in these two studies there is a risk of contamination as both of the instruments assessed were filled out on the very same day. The answers given to the first questionnaire are remembered in the second questionnaire or interview. In our study the great majority of the questionnaires including the DEPS were returned by mail within 2 weeks of the appointment, and the PSE interview took place in another 2 weeks on average [34]. This time delay has very probably impaired the key figures. Compared with the results of the study with the WHO-5, GHQ-12, and B-PHQ and the CIDI telephone interview as the gold standard [20] the DEPS has in general sensitivity and PPV values at about the same level as the best diagnostic instrument (DEPS: 75% and 47% vs. B-PHQ: 79% and 51%), but poorer specificity and NPV (DEPS: 69% and 88% vs. BPHQ: 86% and 95%). When subpopulations were assessed with this same material, the sensitivity of the best detector, the WHO-5, was lower for male patients (5). In our study with the DEPS sensitivity was better for male patients. The DEPS has shown gender neutrality in other studies [35,30] which may be due to its brevity and simple structure. Like the EPDS the DEPS lacks many items on somatic symptoms, which may be an advantage within the perplexing symptoms of primary care patients. As far as we know, there is no established gold standard for a case finding instrument for such patients. The DEPS is suitable for patients with somatic complaints, too, but with a recommendation for a higher cut-off point e 13/14 e on account of better specificity. 4.4. Limitations and strengths of the study Because the participants were aged 18 to 64 the results should be applied with caution to elderly and adolescent

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patients. The study material is relatively old. The validity and functionality of a questionnaire does not, however, depend on its age. Finnish primary care patients may be slightly different now, more than 15 years later. The level of basic education is nowadays generally higher, putting weight on one of the principal findings of this study. A strength of the study was that background characteristics did not differ between those who completed the DEPS and the interview and those who gave an incomplete DEPS score or who refused to participate in the interview. The study material was representative including office hour visits, emergency unit visits, antenatal clinics, and occupational health services, and the material consisted of patients both from an urban centre with a population of 200,000 and from rural surroundings. Exclusion criteria were very sparse. All the interviewers had received thorough official training in the use of the PSE. 5. Conclusion In light of the results of this study the DEPS is suitable for recognizing depression in primary care patients, men and women, and especially suitable for patients with a good basic education. Future studies comparing the DEPS with other simple self-rating questionnaires, comparing it with a structured diagnostic interview on the very same day, and assessing it with other than Finnish patients are needed. References [1] Altman DG, Bland JM. Diagnostic tests 2: predictive values. BMJ 1994 July 9;309(6947):102. [2] Altman DG, Bland JM. Diagnostic tests. 1: sensitivity and specificity. BMJ 1994 June 11;308(6943):1552. [3] Arnau RC, Meagher MW, Norris MP, Bramson R. Psychometric evaluation of the Beck Depression Inventory-II with primary care medical patients. Health Psychol 2001 March;20(2):112e9. [4] Barrett J, Oxman T, Gerber P. Prevalence of depression and its correlates in general medical practice. J Affect Disord 1987;12:167e74. [5] Becht MC, Van Erp CF, Teeuwisse TM, Van Heck GL, Van Son MJ, Pop VJ. Measuring depression in women around menopausal age: towards a validation of the Edinburgh Depression Scale. J Affect Disord 2001 March;63(1e3):209e13. [6] Beck A, Steer R. Beck depression inventory manual. San Antonio: Psychological Corporation; 1993. [7] Beck AT, Steer RA, Ball R, Ranieri W. Comparison of Beck Depression Inventories -IA and -II in psychiatric outpatients. J Pers Assess 1996 December;67(3):588e97. [8] Beck AT, Ward CH, Mendelson M, Mock J, Erbaugh J. An inventory for measuring depression. Arch Gen Psychiatry 1961 June;4:561e71. [9] Bjelland I, Dahl AA, Haug TT, Neckelmann D. The validity of the Hospital Anxiety and Depression Scale. An updated literature review. J Psychosom Res 2002 February;52(2):69e77. [10] Christensen KS, Toft T, Frostholm L, Ornbol E, Fink P, Olesen F. The FIP study: a randomised, controlled trial of screening and recognition of psychiatric disorders. Br J Gen Pract 2003 October;53(495):758e63. [11] Christensen KS, Toft T, Frostholm L, Ornbol E, Fink P, Olesen F. Screening for common mental disorders: who will benefit? Results from a randomised clinical trial. Fam Pract 2005 August;22(4):428e34. [12] Cox JL, Holden JM, Sagovsky R. Detection of postnatal depression. Development of the 10-item Edinburgh Postnatal Depression Scale. Br J Psychiatry 1987 June;150:782e6.

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