Analyses of the 92 schizophrenia endophenotype candidate genes from COGS and the 204 candidate genes we hypothesized might be related to all the endophenotypes examined in this special issue did produce a handful of associations that were nominally significant for both endophenotypes (p < .05). However, these were few in number, and none survived Bonferroni correction. Our failure to find strong evidence of associations with neurotransmitter genes in the endophenotype-general candidate set of 204 is disappointing given empirical and conceptual evidence that P3 amplitude depends critically on several major neurotransmitters. We also did not corroborate previous findings regarding P3 amplitude or related phenotypes, such as event-related theta power. Although several associations were nominally significant (p < .05), this was not the case for both endophenotypes, despite the fact that they were very highly correlated.
