Table 2.

Correlations^* between regional cortical gray matter and clinical variables among twins with schizophrenia (n = 20)

	Region of cortex
Variable	Frontal	Temporal	Parietal	Occipital
Duration of illness	−0.09	−0.05	0.15	0.26
Years ofneuroleptic treatment	−0.01	0.04	0.09	0.01
Negative symptoms (30)	−0.44†	−0.43†	−0.38	−0.23
Positive symptoms (31)	−0.34	−0.29	−0.37	0.03
Disease-related cognitive variate (28)	0.50†	0.52†	0.60†	0.10
Verbal memory (32)	0.59†	0.42†	0.42†	0.30
Visual memory (33)	0.32	0.49†	0.50†	0.20

^*Partial correlations controlling for overall brain volume. 

†, P < 0.05.