Table 2.

Demographic characteristics¹ of the patient and healthy control groups

Characteristic	NC (n = 316)	SZ (n = 106)	BD (n = 66)	Statistic	p <
Age (years)	54.5 ±18.6a	40.0 ±11.1b	41.5 ±11.5b	F(2,483) = 39.6	0.001
Sex (male:female %)	44:56a	69:31b	38:62a	${\chi }_{(2)}^2=23.2$	0.001
Race (w:b:o %)	81:17:2a	40:55:6b	67:29:5c	${\chi }_{(4)}^2=64.4$	0.001
Education (years)	14.3 ±3.0a	12.0 ±2.4b	14.8 ±3.0a	F(2,483) = 27.6	0.001
Est. premorbid IQ	105.2 ±10.1a	96.5 ±10.5b	103.7 ±10.9a	F(2,483) = 28.3	0.001
Age at onset (years)	–	22.9 ±7.5	24.9 ±9.0	t(98.5) = -1.5	0.163
Illness duration (years)	–	17.1 ±10.5	16.3 ±11.1	t(143) = 0.5	0.647
# Hospitalizations	–	5.4 ±6.5	4.2 ±4.4	t(143) = 1.2	0.244
SANS (sum)	–	10.0 ±6.4	2.5 ±2.9	t(83.6) = 7.8	0.001
SAPS (sum)	–	5.1 ±4.1	1.8 ±2.6	t(90.6) =4.3	0.001
Typical antipsychotic (%)	–	34	4	${\chi }_{(1)}^2=15.0$	0.001
Atypical antipsychotic (%)	–	75	47	${\chi }_{(1)}^2=13.1$	0.001
Any antidepressant (%)	–	23	48	${\chi }_{(1)}^2=11.3$	0.001
Lithium (%)	–	4	50	${\chi }_{(1)}^2=42.3$	0.001
Any anticonvulsant (%)	–	13	42	${\chi }_{(1)}^2=18.4$	0.001

Note: For three-group analyses, different subscripts denote significant (p < .05) differences. SZ = schizophrenia; BD = bipolar disorder; NC = normal control. Estimated premorbid IQ based on the NART-R (Blair and Spreen 1989).

¹Shown as mean ±standard deviation unless otherwise indicated.

²For race, w = white, b = black, o = “other.”