Table I. Neurophysiological and neuropsychological endophenotypes: effect size difference between schizophrenia patients, normal comparison groups, and schizophrenia spectrum groups. Effect sizes in schizophrenia patients, clinically unaffected relatives of schizophrenia patients, and schizotypal personality disordered patients compared with those in normal subjects. These effect sizes were computed by using the mean and standard deviations for normal comparison subjects and the means of the patient groups. The range of values differs from study to study because different investigators used different patient populations taking different types and amounts of medications; also, multiple conditions were used, some of which were needed to establish the floor and ceiling effect. In these cases, we generally cited the most robust effect sizes. ^*Also, Cadenhead KS, unpublished data, 2000.

Endophenotypes	Schizophrenia patients	Relatives of schizophrenia patients	Schizotypal personality disordered patients	References
Antisaccade	4.88-6.38	1.38-3.75	0.75-1.36	15, 16
Smooth-pursuit eye movement	2.0-3.0	0.29-1.3	0.29	16-18
Thought disorder	1.56-2.98	0.34-0.83	1.04-1.28	16, 19-21
Working memory	1.42-2.2	0.42	0.73-1.04	22-24
P50 suppression	0.92-1.29	0.79	0.79	25, 27
Reaction time	0.59-1.05	0.44	0.79-0.99	28-30
Prepulse inhibition	0.51-0.85	1.0	1.45	31-33
Span of apprehension	0.5-2.5	0.6-1.5		34-39
Continuous performance test	0.45-3.30	0.46-2.97	0.45-0.78	34, 40-42
Executive functioning	0.47-1.97	0.73-1.6	0.72	40, 43
P300 event-related potential	0.45-1.05	0.17	0.36	44,45
Visual backward masking	0.33-0.65	0.43-0.57	0.45-0.67	28, 46, 47*