There is currently tension in the field of psychopathology regarding recent scientific initiatives that seek to incorporate neurobiological concepts and measures into models of psychopathology, particularly with regard to significant methodological challenges facing such endeavors. In order to establish multimodal models of psychopathology that include brain and behavioral indicators along with report-based measures, a methodological strategy is needed for addressing basic psychometric issues common to lab-task measures. This chapter describes an iterative psychoneurometric research strategy to addressing such issues. This approach focuses on neurobehavioral traits – i.e., latent dispositions that manifest in brain and behavioral responses within lab tasks as well as in self-reported proclivities. The chapter provides an overview of this approach and illustrates its use in developing a multimodal model for inhibitory control capacity (inhibition-disinhibition), a neurobehavioral trait that confers liability for externalizing forms of psychopathology (substance problems, delinquency, and aggression) as well as internalizing disorders marked by pervasive and unregulated distress. It discusses how the psychoneurometric approach can be extended to other neurobehavioral traits (e.g., threat sensitivity) that operate as liabilities for psychopathology, and how multimodal models of core trait liabilities can serve as anchors for an integrative, measurement-based framework for understanding, assessing, and treating mental health problems.