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Table 3 Adjusted z scores of d′ on the Continuous Performance Test (CPT) among the study participants with group comparisons

From: Severity in sustained attention impairment and clozapine-resistant schizophrenia: a retrospective study

 

Non-TRS

(Group 1)

TRS without CR

(Group 2)

TRS with CR

(Group 3)

Group comparisons

Significant post hoc comparisons§

CPT indices

(N = 102)

(N = 48)

(N = 54)

   

Continuous

Mean

(SD)

Mean

(SD)

Mean

(SD)

F

p

 

Undegraded CPT

 Adjusted z score of d′

−2.14

(1.98)

−3.31

(2.62)

−4.26

(2.21)

11.91

<  0.0001†

1 > 3, 2 > 3

Degraded CPT

 Adjusted z score of d′

−1.73

(1.60)

−2.65

(1.80)

−3.29

(1.19)

10.88

<  0.0001†

1 > 3, 2 > 3

Binary

N

(%)

N

(%)

N

(%)

χ2

p

 

Undegraded CPT deficit

 Adjusted z score of d′ ≤ −2.5

38

(37.3)

27

(56.3)

44

(81.5)

27.96

0.0001‡

1 < 3, 2 < 3

Degraded CPT deficit

 Adjusted z score of d′ ≤ −2.5

37

(36.3)

30

(62.5)

45

(83.3)

33.04

<  0.0001‡

1 < 2 < 3

  1. CPT continuous performance test, TRS treatment-resistant schizophrenia, CR clozapine resistance, d′, the sensitivity index of performance on the CPT
  2. †ANCOVA for continuous variables with covariates including illness duration, number of hospitalizations, the scale of Clinical Global Impression-Severity, early onset or not, smoking status, current antipsychotic dosage, and atypical-antipsychotic user or not
  3. ‡χ2 test for categorical variables
  4. §Tukey-Kramer adjustment for ANCOVA; a Tukey-type multiple comparison for proportions in a 2*3 cross-tabulations [43]