Context There are many published twin studies of schizophrenia. Although these studies
have been reviewed previously, to our knowledge, no review has provided quantitative
summary estimates of the impact of genes and environment on liability to schizophrenia that
also accounted for the different ascertainment strategies used. Objective To calculate meta-
analytic estimates of heritability in liability and shared and individual-specific environmental
effects from the pooled twin data. Data Sources We used a structured literature search to …