Table I.

Reliability statistics of the items of the GHQ-28

Item-total statistics
Name of scales	Questions	Scale mean if item deleted	Scale variance if item deleted	Corrected item-total correlation	Cronbach alpha if item deleted
A1	1	22.24	111.713	0.362	0.898
A2	2	22.33	114.118	0.239	0.901
A3	3	22.20	109.157	0.573	0.894
A4	4	22.38	109.712	0.547	0.894
A5	5	22.29	113.322	0.293	0.900
A6	6	22.61	111.948	0.386	0.898
A7	7	22.10	110.675	0.441	0.897
B1	8	22.04	107.853	0.542	0.894
B2	9	22.09	109.381	0.485	0.896
B3	10	22.25	112.143	0.347	0.899
B4	11	22.01	107.934	0.623	0.893
B5	12	22.32	107.769	0.637	0.892
B6	13	22.51	108.908	0.568	0.894
B7	14	21.87	108.383	0.537	0.894
C1	15	22.25	113.664	0.388	0.897
C2	16	22.11	116.153	0.211	0.900
C3	17	22.23	112.724	0.442	0.896
C4	18	22.26	113.556	0.427	0.897
C5	19	22.34	114.844	0.324	0.898
C6	20	22.24	112.962	0.451	0.896
C7	21	22.17	111.934	0.456	0.896
D1	22	22.73	108.818	0.620	0.893
D2	23	22.64	109.490	0.548	0.894
D3	24	22.79	109.413	0.608	0.893
D4	25	23.02	114.126	0.398	0.897
D5	26	22.60	109.744	0.555	0.894
D6	27	22.88	109.431	0.649	0.893
D7	28	23.04	114.102	0.477	0.896

GHQ-28: General Health Questionnaire-28

Items A: physical symptoms (questions 1-7), B: anxiety and insomnia (questions 8-14), C: social dysfunction (questions 15-21), D: depression (questions 22-28).