Table 1. Parameter estimates of the Item Response Model of all 14 items in the DSM-IV and ICD-10.
Proportions of patients endorsed, item parameter estimates (95% credible intervals(CI)) in the model with all 14 items (left side) and in the model excludes two core symptoms (right side), using Item Response Theory among respondents in a community of Japan who endorsed either depressive mood or markedly diminished interest for two weeks (n=353): The World Mental Health Japan 2002–2004 Survey
| Symptom | Criteria | Propor -tion |
Item parameters in the model with all items |
Item parameters in the model excluding core items |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Discrimination |
Threshold |
Infit/ Outfit |
Discrimination |
Threshold |
Infit/ Outfit |
|||||||
| Median | (95% CI) | Median | (95% CI) | Median | (95% CI) | Median | (95% CI) | |||||
| Depressed mood | DSM | 0.94 | 0.09 | (−0.23:0.42) | −7.50 | (−139.34:137.29) | 1.03/1.02 | - | - | - | - | - |
| Loss of interest (anhendonia) | DSM & ICD | 0.87 | 0.51 | (0.27:0.79) | −2.52 | (−4.48:−1.76) | 1.00/0.90 | - | - | - | - | - |
| Weight or appetite changes | DSM | 0.71 | 0.40 | (0.21:0.60) | −1.45 | (−2.61:−0.93) | 0.95/0.94 | 0.39 | (0.20:0.59) | −1.50 | (−2.79:−0.97) | 0.96/0.96 |
| Sleep problems | DSM & ICD | 0.85 | 0.48 | (0.25:0.74) | −2.36 | (−4.20:−1.62) | 0.98/0.92 | 0.46 | (0.24:0.73) | −2.43 | (−4.46:−1.66) | 0.98/0.96 |
| Objective psychomotor activity | DSM | 0.17 | 1.03 | (0.67:1.56) | 1.42 | (1.12:1.88) | 0.88/0.54 | 1.06 | (0.68:1.64) | 1.34 | (1.05:1.79) | 0.89/0.55 |
| Fatigability | DSM & ICD | 0.78 | 0.64 | (0.41:0.92) | −1.40 | (−2.06:−1.03) | 0.91/0.84 | 0.70 | (0.45:0.98) | −1.35 | (−1.92:−1.00) | 0.91/0.87 |
| Worthlessness | DSM | 0.23 | 1.15 | (0.76:1.72) | 1.03 | (0.79:1.36) | 0.76/0.49 | 1.51 | (0.94:2.44) | 0.89 | (0.68:1.17) | 0.69/0.38 |
| Concentration difficulty | DSM & ICD | 0.81 | 0.89 | (0.60:1.26) | −1.30 | (−1.76:−100) | 0.86/0.66 | 0.94 | (0.63:1.32) | −1.29 | (−1.72:−1.00) | 0.87/0.68 |
| Suicidal ideation | DSM & ICD | 0.61 | 0.52 | (0.33:0.74) | −0.58 | (−0.99:−0.28) | 0.91/0.88 | 0.55 | (0.36:0.77) | −0.58 | (−0.97:−0.30) | 0.92/0.89 |
| Loss of confidence | ICD | 0.74 | 0.86 | (0.58:1.20) | −0.96 | (−1.33:−0.70) | 0.83/0.68 | 0.95 | (0.66:1.32) | −0.93 | (−1.25:−0.69) | 0.83/0.68 |
| Self-reproach | ICD | 0.41 | 0.91 | (0.61:1.33) | 0.40 | (0.20:0.63) | 0.78/0.67 | 1.13 | (0.74:1.72) | 0.32 | (0.15:0.53) | 0.75/0.61 |
| Psychomotor symptom (objective or subjective) | ICD | 0.50 | 0.75 | (0.51:1.05) | 0.04 | (−0.18:0.26) | 0.83/0.76 | 0.79 | (0.53:1.11) | 0.00 | (−0.21:0.22) | 0.85/0.78 |
| Weight and appetite change | ICD | 0.11 | 0.38 | (0.14:0.65) | 3.47 | (2.20:8.50) | 1.02/0.92 | 0.38 | (0.14:0.65) | 3.41 | (2.13:8.76) | 1.02/0.93 |
| Nonreactive depressed mood | ICD | 0.97 | 0.18 | (−0.26:0.61) | −6.86 | (−107.69:95.15) | 1.07/1.01 | 0.30 | (−0.12:0.75) | −5.94 | (−59.29:46.18) | 1.08/0.95 |