Table 1 Characteristics of each factor model tested in earlier studies.
Model, author, year | Number of factors | Clinical population | n | Factor extraction method # | Allocation of items to scales |
|---|---|---|---|---|---|
Zigmond & Snaith (1983) | 2 | Medical | 100 | No Factor analysis conducted | anxiety: 1, 3, 5, 7, 9, 11, 13 depression: 2, 4, 6, 8, 10, 12, 14 |
Moorey et al. (1991) | 2 | Cancer | 568 | PCA | anxiety: 1, 3, 5, 9, 11, 13 depression: 2, 4, 6, 7, 8, 10, 12, 14 |
Dunbar et al. (2000) | 3 | Non-clinical | 2,547 | CFA | autonomic anxiety: 3, 9, 13 negative affectivity: 1, 5, 7, 11 anhedonic depression: 2, 4, 6, 7, |
Friedman et al. (2001)* | 3 | Depressed | 2,669 | PCA | psychomotor agitation: 1, 7, 11 psychic anxiety: 3, 5, 9, 13 depression: 2, 4, 6, 8, 10, 12 |
Razavi et al. (1990) | 1 | Cancer | 210 | PCA | All items included |
Caci et al. (2003) | 3 | Non-clinical | 195 | CFA | anxiety: 1, 3, 5, 9, 13 restlessness: 7, 11, 14 depression: 2, 4, 6, 8, 10, 12 |