Another promising future direction is studies of sex differences in disorder endophenotypes that are posited to more closely reflect underlying genetic influences. There are several examples of studies that have identified endophenotypes for psychiatric disorders, including depression, 138 , 139 ADHD, 140 ASD, 141 and schizophrenia. 142 Systematic exploration of sex differences in studies of endophenotypes could provide more comprehensive depiction of the spectrum of expression of genetic factors underlying major categorical diagnoses in psychiatry between the sexes. Similar to the large case‐control GWAS, most studies of endophenotypes (or subphenotypes) of schizophrenia and bipolar disorder do not systematically investigate sex differences. 143
