We carried out a meta-analysis of published studies reporting data on the association between COMT genotype and Wisconsin Card Sorting Task (WCST) performance (in particular, perserverative errors), a recognized measure of precortical function (Goldberg & Weinberger, 1988). Recall that our recent meta-analysis of COMT genotype and schizophrenia case status (Munafo et al. 2005) described above did not offer any evidence in support of association between the gene and the disease, so a positive association with the endophenotype would be evidence that the endophenotype strategy is more powerful, regardless of the effect size. Analysis of the association between COMT genotype and WCST performance should provide a good test of the value of the endophenotype approach in genetics.
