As shown in table 1, memory is significantly impaired
in schizophrenia. All analyses yielded highly significant
z values for the difference in memory performance
between patients with schizophrenia and
comparison subjects. The magnitude of the overall effect
size of the composite long-term recall measures
was large—d=1.21. In this overall analysis, 60 studies
were included, with a total group size of 3,315 (with
study groups ranging in size from N=16 to N=254). Effect
sizes ranged from 0.44 to 3.10. The homogeneity
statistic showed significant heterogeneity among studies.
The funnel plot (figure 1) demonstrates the characteristic
inverted funnel. However, the lower left portion
of the funnel is less pronounced than the right