Table 2.

Schizophrenia Group Differences after Adjusting for Group Differences in Duration of Illness, Severity of Negative Symptoms, or Proxy for Deficit Syndrome Scores.

	Severity of Negative Symptoms			Proxy for Deficit Syndrome			Duration of Illness
Dependant Variables	F	df	p-value	F	df	p-value	F	df	p-value
PANSS positive syndrome score	2.51	1, 827	0.114	3.75	1, 834	0.053	1.56	1, 839	0.212
PANSS general psychopathology	5.48	1, 827	0.019	9.00	1, 834	0.003	4.99	1, 838	0.026
WCST Perseverative responses	4.06	1, 410	0.044	5.13	1, 411	0.024	0.96	1, 414	0.328
CVLT Memory score	6.94	1, 224	0.009	6.70	1, 229	0.010	0.04	1, 228	0.844
Digit Symbol	12.44	1, 486	0.001	17.85	1, 487	0.001	8.31	1, 490	0.004
Block Design	4.95	1, 304	0.027	5.92	1, 307	0.016	5.24	1, 307	0.023
UPSA	10.40	1, 459	0.001	10.96	1, 456	0.001	8.43	1, 460	0.004
SSPA	10.19	1, 505	0.002	10.58	1, 505	0.001	8.88	1, 508	0.003
Adjusted QWB	6.82	1, 552	0.009	10.14	1, 558	0.002	4.64	1, 560	0.032

Note: Due to significant age and gender differences among the groups (Table 1), each of the outcome variables was replaced with a standardized age- and gender-corrected version. (Please see the section on Statistical Analysis for details.)

Abbreviations:

CVLT – California Verbal Learning Test

PANSS – Positive And Negative Syndrome Scale

QWB – Quality of Well-Being scale

WCST – Wisconsin Card Sorting Test