Abnormal N400 Semantic Priming Effect May Reflect Psychopathological Processes in Schizophrenia: A Twin Study

Table 1

Clinical characteristics: mean values (standard deviation).

Group		SCAN	Age years	Gender M: male; F: female	Handedness; R: right; L: left; AMBI: ambidextrous	Schooling years	BPRS
Concordant affected; (both twins of the pair diagnosed with schizophrenia/schizoaffective disorder)	12	12 schizophrenia	31.2 (7.6)	4 F, 8 M	11 R, 1 L	11.1 (2.4)	35.2 (17.3)
Discordant affected; (twins of discordant pairs diagnosed with schizophrenia/schizoaffective disorder)	11	7 schizophrenia; 1 schizotypal; 3 schizoaffective	31.1 (10.5)	5 F, 6 M	11 R	10.5 (1.4)	28.5 (7.4)
Discordant unaffected; (twins of discordant pairs not diagnosed with schizophrenia/schizoaffective disorder)	11	—	31.1 (10.5)	5 F, 6 M	8 R, 2 L, 1 AMBI	10.9 (1.8)	—
Concordant healthy; (both twins of the pair healthy)	38	—	32.1 (10.2)	20 F, 18 M	36 R, 1 L, 1 AMBI	11.3 (2.0)	—

SCAN: Schedules for Clinical Assessment in Neuropsychiatry; BPRS: Brief Psychiatric Rating Scale.