Table 3.
Item content and IRT item parameter estimates.
| Symptom | Items on the PHQ-9 | a(SE) | b1(SE) | b2(SE) | b3(SE) | Items on the HAMD-17 | a(SE) | b1(SE) | b2(SE) | b3(SE) | b4(SE) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Interest | P1: Little interest or pleasure in doing things | 2.41(0.10) | −1.88(0.07) | −0.55(0.88) | 0.29(0.06) | H7: Work and activities | 1.42(0.07) | −1.87(0.09) | −0.62(0.07) | 1.74(0.24) | 3.00(3.79) |
| Mood | P2: Feeling down, depressed, or hopeless | 2.80(0.11) | −1.75(0.06) | −0.42(0.07) | 0.46(0.07) | H1: Depressed mood (sadness, hopeless, helpless, worthless) | 1.73(0.07) | −1.87(0.08) | −0.75(0.08) | 0.34(0.06) | 2.27(1.13) |
| Sleep | P3: Trouble falling or staying asleep, or sleeping too much | 1.45(0.07) | −1.92(0.09) | −0.52(0.07) | 0.47(0.07) | H4: Insomnia: early in the night; | 1.07(0.06) | −0.55(0.06) | 0.64(0.08) | ||
| H5: Insomnia: middle of the night; | 0.80(0.06) | −1.05(0.10) | 1.61(0.16) | ||||||||
| H6: Insomnia: early hours of the morning | 0.78(0.06) | −0.24(0.07) | 1.73(0.21) | ||||||||
| Energy | P4: Feeling tired or having little energy | 2.46(0.10) | −1.99(0.07) | −0.71(0.09) | 0.22(0.07) | H13: General somatic symptoms | 1.41(0.07) | −1.10(0.07) | 0.61(0.05) | ||
| Diet | P5: Poor appetite or overeating | 1.49(0.07) | −1.37(0.07) | −0.14(0.05) | 0.96(0.11) | H12: Somatic symptoms gastro-intestinal | 1.23(0.07) | −0.30(0.05) | 2.03(0.32) | ||
| Pessimism | P6: Feeling bad about yourself | 2.38(0.10) | −1.42(0.06) | −0.33(0.05) | 0.48(0.06) | H2: Feelings of guilt | 1.35(0.07) | −1.19(0.07) | −0.05(0.04) | 2.01(0.38) | 4.73(48.19) |
| Attention and anxiety | P7: Trouble concentrating on things | 1.63(0.07) | −1.43(0.07) | −0.18(0.05) | 0.84(0.10) | H8: Retardation | 1.06(0.06) | −1.52(0.10) | 1.88(0.19) | 6.18(71.01) | /a |
| P8: Moving or speaking so slowly that other people could have noticed− Or so fidgety or restless that you have been moving a lot more than usual | 1.55(0.08) | −0.45(0.05) | 0.59(0.06) | 1.68(0.41) | H9: Agitation | 0.98(0.06) | −1.04(0.08) | 1.20(0.11) | 2.99(0.98) | 3.40(4.66) | |
| H10: Anxiety psychic | 1.15(0.06) | −1.81(0.10) | −0.12(0.05) | 1.27(0.15) | 5.54(45.81) | ||||||
| Suicide | P9: Thoughts that you would be better off dead, or thoughts of hurting yourself in some way | 2.04(0.09) | −0.43(0.04) | 0.78(0.08) | 1.64(0.75) | H3: Suicide | 1.72(0.08) | −0.54(0.05) | 0.17(0.04) | 0.73(0.11) | 2.79(3.46) |
| Other | H11: Anxiety somatic | 1.27(0.06) | −1.38(0.08) | 0.09(0.04) | 1.81(0.29) | 4.21(13.31) | |||||
| H14: Genital symptoms | 0.54(0.07) | 1.54(0.20) | /b | ||||||||
| H15: Hypochondriasis | 0.52(0.05) | 0.39(0.10) | 2.37(0.38) | 8.73(11.64) | 14.42(1056.55) | ||||||
| H16: Loss of weight | 0.75(0.07) | 1.32(0.12) | 2.47(0.56) | ||||||||
| H17: Insight | −0.02(0.07) | −97.38(384.19) | −227.05(915.78) |
a
Stupor was excluded in this study because the patient was unable to cooperate with the assessment.
b
This option indicates that it is not certain, or that it is not suitable for the patient (not included in the total score).
PHQ-9, the Patient Health Questionnaire-9; HAMD, the Hamilton Rating Scale for Depression.
Bold text represented HAMD-6 items.