This commentary reflects on Jang and Choi’s (this volume) chapter summarizing the extent work on behavior and molecular genetic studies of personality disorder (PD). The authors argue that more work needs to be done on refining the PD phenotype, as most work in genetics to date has utilized categorical definitions of PD, even though clinical psychology generally and the field of PDs specifically is moving resolutely toward a dimensional conceptualization (as represented in the alternative model of PDs in the DSM-5). They also argue that the real benefit of both quantitative and measured gene approaches to studying PDs might not be the elucidation of more precise heritability estimates or even the identification of specific genes, but the contribution of environmental influences to maladaptive personality traits.