Main findings
In this study, the HADS was validated on a sample of Pakistani pregnant women living in the district of Abbottabad. Our findings are of clinical importance in terms of validation of a screening tool for anxiety and depression. The HADS/UV proved to be acceptable for pregnant women.
The language of the original English questionnaire was highly metaphorical, and some items had to be carefully translated to adapt to the Urdu language of the Pakistani population. Translation of the HADS items faced some problems, and some items were retranslated at least twice, especially item 8 D4, item 9 A5 and item 11 A6, because of ambiguity of words. Ambiguity was also noticed with the Polish20 and Malayalam versions.14 In our opinion, the translation was sufficient; however, further scrutiny of the meaning is suggested to match with the Urdu language and local context.
The original research of HADS tested its psychometric soundness on a group of hospitalised patients who suffered from different diseases. The scale is proven to be valid and reliable for other groups of patients as well: for oncology,21 22 HIV-infected patients,23 hospitalised elderly,24 gynaecology patients,12 14 patients with coronary artery diseases,25 patients in the emergency department26 and among patients in primary healthcare.27 In turn, our study contributes to the body of knowledge about irregularities of psychometric findings of HADS noticed in the literature28 when it is applied on patients with chronic diseases to others who suffer from physiological changes during pregnancy.
With regard to content validity, the CVI of HADS items revealed high and excellent agreement among experts (k≥0.88), indicating good content validity, except for item 11 A6 (k=0.72), which is below the recommended value (k>0.75).29 Therefore, the question should be reconsidered to make it more understandable and culturally suitable. The S-CVI of the HADS subscales, anxiety and depression, was above the recommended value (0.90).30 Similarly, Zimmermann et al
29 stated that an S-CVI score above 0.83 is sufficient and satisfactory, indicating no ambiguity in understanding the questionnaire. The satisfactory S-CVI indicates cultural relevance.
The HADS/UV of both scales is comparable to previous studies12 31 and showed satisfactory internal consistency. The Cronbach alpha of HADS scales was good (α=0.84) and above recommended value and met Klines' criteria.20 The Cronbach alpha coefficient of the HADS subscales was good for anxiety (α=0.82) but below the recommended value for depression (α=0.64). By and large, the HADS-A subscale showed better psychometric properties than the HADS-D.13 Our study has reported good reliability scores; hence, we recommend that HADS/UV should be used in the clinical setting for screening of anxiety and depression in Pakistan.
Test–retest reliability was also excellent and intraclass correlation was 0.93, which was similar to that of previous studies32 and better than that of the Hyland et al study.21 The stability of the test–retest score over 2 weeks and high alpha coefficient support the strength of the HADS for use among pregnant women. Correlation between two factors, HADS-A and HADS-D, was excellent (0.667), similar to the Greek,33 Iranian,22 Arabic26 and Pashto versions.9 The correlation was strong between HADS of both scales and the subscale scores.21 22 26
The EFA showed unequal distribution of items among the two factors, especially for factor 2. It was bidimensionally similar to the original English published by Zigmond and Snaith34 Majority of ex-studies documented the two-factor model,9 12 13 22 23 26 33 and some reported three factors.20 25 Three exceptions were found, which reported a unidimensional model.23 In the EFA, most items of the HADS-A were loaded in factor 1 except for item 9 A5. A5 was also an unstable item and problematic in Iranian22 and Arabic26 translations. In contrast, item 14 (D7) was loaded less than 0.3 in factor 2 (depression); item ‘D7’ load remained <0.3 in factor 1 (anxiety). Items ‘A4’, ‘D3’ and ‘A7’ shared their loadings between factor 1 and 2. So, we would recommend that it is better to rephrase this item 14 (D7) in future studies as it asks about enjoying a good book, radio or TV programme, and it gave us mixed response due to the different medium of entertainment sources.
In turn, the extracted factors’ correlation matrix showed no high correlation, typically between 0.03 and 0.545, in the initial factor analysis, and very few items were highly correlated with others (>0.50). Items 10 'D5' and item 14 'D7' correlated low (>0.2) with most items. This irregularity of items' distribution and low correlation were observed in the Karimova and Martin31 study and suggests an unsatisfactory model and could be attributed to the impact of biological changes occurring during pregnancy on the perception of emotional components of the HADS. The explained variance of the HADS/UV is 42.75%, which is quite similar to Waqas et al
12 and a bit far from the Watrowski and Rohde20 finding in the same population.