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Table 3 Item characteristics of the Patient Health Questionnaire-9 (PHQ-9) items stratified for sex

From: Bidimensional structure and measurement equivalence of the Patient Health Questionnaire-9: sex-sensitive assessment of depressive symptoms in three representative German cohort studies

Total

   

1 factor model

2 factor model

Bifactor model

   

General factor

S

CA

 

Mean

SD

λ

λ

λ

λ

λ

Anhedonia (CA)

0.53

0.66

0.624

0.603

0.381

 

0.105

depressed mood (CA)

0.33

0.57

0.743

0.742

0.378

 

0.211

sleep disturbances (S)

0.92

0.92

0.532

0.532

0.447

0.160

 

fatigue (S)

0.84

0.75

0.733

0.734

0.542

0.428

 

appetite changes (S)

0.38

0.66

0.579

0.567

0.367

0.028

 

low self-esteem (CA)

0.23

0.52

0.608

0.624

0.279

 

0.194

concentration difficulties (CA)

0.41

0.63

0.544

0.554

0.369

 

0.029

psychomotor disturbances (S)

0.16

0.46

0.439

0.434

0.223

−0.060

 

suicidal ideation (CA)

0.07

0.30

0.499

0.509

0.122

 

0.114

Total

0.43

0.61

     

Latent factor correlation

   

0.875

   

McDonald’s ω

  

0.963

0.947CA/ 0.891 S

0.830

0.700

0.748

Women

   

1 factor model

2 factor model

Bifactor model

   

General factor

S

CA

 

Mean

SD

λ

λ

λ

λ

λ

Anhedonia (CA)

0.56

0.66

0.614

0.624

0.386

 

0.123

depressed mood (CA)

0.39

0.60

0.720

0.743

0.408

 

0.293

sleep disturbances (S)

1.04

0.94

0.495

0.532

0.440

0.212

 

fatigue (S)

0.92

0.77

0.685

0.733

0.524

0.425

 

appetite changes (S)

0.45

0.71

0.553

0.579

0.389

0.086

 

low self-esteem (CA)

0.27

0.55

0.592

0.608

0.314

 

0.099

concentration difficulties (CA)

0.45

0.66

0.551

0.544

0.404

 

−0.076

psychomotor disturbances (S)

0.17

0.47

0.443

0.439

0.234

−0.047

 

suicidal ideation (CA)

0.09

0.32

0.487

0.499

0.143

 

0.069

Total

0.48

0.63

     

Latent factor correlation

   

0.883

   

McDonald’s ω

  

0.960

0.945CA/0.889 S

0.832

0.691

0.763

Men

   

1 factor model

2 factor model

Bifactor model

   

General factor

S

CA

 

Mean

SD

λ

λ

λ

λ

λ

Anhedonia (CA)

0.50

0.66

0.578

0.583

0.370

 

0.099

depressed mood (CA)

0.28

0.55

0.713

0.733

0.347

 

0.187

sleep disturbances (S)

0.80

0.88

0.460

0.510

0.456

0.086

 

fatigue (S)

0.75

0.73

0.663

0.722

0.537

  

appetite changes (S)

0.32

0.59

0.514

0.539

0.320

−0.082

 

low self-esteem (CA)

0.20

0.48

0.622

0.641

0.247

 

0.239

concentration difficulties (CA)

0.37

0.61

0.566

0.560

0.340

 

0.083

psychomotor disturbances (S)

0.15

0.44

0.428

0.430

0.188

−0.033

0.118

suicidal ideation (CA)

0.06

0.26

0.501

0.516

0.106

  

Total

0.38

0.58

     

Latent factor correlation

   

0.865

   

McDonald’s ω

  

0.960

0.949CA/0.897 S

0.779

0.487

0.742

  1. Note: SD = standard deviation, factor loadings (λ) are standardized. Index CA = cognitive-affective dimension, S = somatic dimension. Mean values are item level based and pooled for all cohorts. The sample differs for each item and deviates slightly from the general sample that was defined based on PHQ-9. The reason for this is that, in the GHS study, missing values for PHQ-9 were only allocated in case of missing values of at least three individual items, otherwise the total PHQ-9 score was calculated by implementing the mean score of the non-missing items for the missing items