Table 1.

Characteristics of Patients

Variables	TRS with clozapine	TRS without clozapine	ND-TRS without clozapine	P 1	P 2	P 3
n	426	414	6346
Female (%)	n = 236 (55.4)	n = 235 (56.8)	n = 3465 (54.6)	1.0	1.0	1.0
Age (y)	41.6 (11.8)	45.8 (14.3)	46.2 (15.8)	1.4 × 10−4	1.1 × 10−8	1.0
Prescription clozapine at admission (%)	n = 189 (44.4)	n = 8 (1.9)	n = 7 (0.1)	< 2.0 × 10−16	< 2.0 × 10−16	2.4 × 10−6
Mean dose of clozapine at admission (mg/d)4	364.6 (175.6)	370.3 (168.2)	332.1 (192.1)	1.0	1.0	1.0
Electroconvulsive therapy during hospitalization (%)	n = 36 (8.5)	n = 100 (24.2)	n = 264 (4.2)	1.8 × 10−9	4.1 × 10−4	< 2.0 × 10−16

Abbreviations: ND-TRS, no description of TRS; TRS, treatment-resistant schizophrenia. Values are expressed as the mean (SD) except for (%). Fisher’s exact test or the Mann–Whitney U test was adjusted by Bonferroni’s correction for post hoc analyses, and P < 6.2 × 10⁻⁴ (0.05/81) was defined as significant.

¹Comparison between the TRS with clozapine and TRS without clozapine groups using the Mann–Whitney U test or Fisher’s exact test with Bonferroni correction.

²Comparison between the TRS with clozapine and ND-TRS without clozapine groups using the Mann–Whitney U test or Fisher’s exact test with Bonferroni correction.

³Comparison between the TRS without clozapine and ND-TRS without clozapine groups using the Mann–Whitney U test or Fisher’s exact test with Bonferroni correction.

⁴The mean dose of clozapine in patients for whom clozapine was prescribed at admission.