Table 3.

Neuropsychological performance (raw scores) in schizophrenia and healthy participant groups.

	Low IQ IQ 80–95			Normal IQ IQ 100–115			Superior IQ IQ ≥ 120			Overall effect size SZ-HC differences across IQ-strata	ANCOVA
	SZ-low, n = 65, M (SD) range	HC-low, n = 13, M (SD) range	Effect size SZ-HC differences	SZ-normal, n = 111, M (SD) range	HC-normal, n = 115, M (SD) range	Effect size SZ–HC differences	SZ-superior, n = 20, M (SD) range	HC-superior, n = 50, M (SD) range	Effect size SZ-HC differences		Group, F-value	IQ, F-value	Group × IQ, F-value
Grooved Pegboard (composite)	90.5 (35.2)a	69.2 (8.6)	0.97	74.9 (12.3)	65.9 (8.6)d	0.86	69.8 (8.2)	62.0 (6.8)	1.04	0.91	35.3**	8.4**	2.6
	60–289	59–84		57–122	48–112		58–98	50–83
Digit symbol	51.6 (13.4)b	66.7 (11.5)	1.21	60.3 (13.2)	74.7 (13.2)	1.09	73.9 (12.0)	81.5 (12.7)	0.62	1.22	52.1**	29.2**	3.4
	22–82	45–83		33–101	47–111		50–93	54–109
Digit span (composite)	9.1 (1.6)	9.8 (2.4)	0.35	10.4 (1.6)	11.0 (1.9)	0.34	11.0 (1.5)	12.1 (2.1)	0.61	0.64	10.7**	16.5**	0.5
	6–12	6–14		7–15	7–16		8–13	8–17
Logical memory learning	17.8 (6.3)b	21.8 (6.3)	0.64	22.2 (7.5)c	25.6 (6.0)	0.50	25.7 (6.8)e	30.3 (6.2)	0.71	0.80	13.9**	20.9**	0.2
	6–38	6–30		8–37	12–41		15–38	14–45
Phonemic fluency	30.1 (9.5)	30.9 (6.0)	0.10	37.8 (11.7)	43.4 (10.5)	0.50	45.1 (10.2)	51.6 (10.1)	0.64	0.76	5.5*	38.5**	1.0
	8–47	23–40		16–80	17–74		30–69	28–72
Semantic fluency	34.2 (8.1)	40.7 (8.4)	0.79	39.7 (9.1)	47.2 (8.4)	0.86	45.9 (8.0)	52.1 (7.6)	0.80	1.06	28.3**	24.5**	0.2
	19–53	24–55		23–75	23–76		31–62	35–72
Category switching	11.4 (2.5)	12.5 (2.5)	0.44	12.2 (2.5)	14.7 (2.8)	0.94	13.8 (2.2)	16.3 (2.3)	1.11	1.07	25.9**	20.7**	0.7
	6–17	7–17		5–18	4–23		10–17	11–23
Inhibition	67.2 (18.6)	55.5 (8.0)	0.89	58.2 (13.7)	50.8 (10.1)	0.62	51.3 (11.2)	45.3 (8.2)	0.62	0.48	18.1**	15.0**	0.8
	35–120	38–69		34–104	31–95		35–77	30–70

^an  = 62, ^bn  = 64, ^cn = 108, ^dn = 114, ^en  = 18.

**p < 0.01, *p < 0.05.