Irritability as a Transdiagnostic Vulnerability Trait: Current Issues and Future Directions

In recent years, irritability has received increasing attention among mental health professionals given its transdiagnostic associations with diverse forms of psychopathology. In contrast to other emotional states and traits, however, literature addressing associations between irritability and related temperament and personality constructs is limited. In addition, those who study irritability have diverse perspectives on its neurobiological substrates. In this comment, we situate irritability in the literatures on child temperament and adult personality, and describe a model in which irritability derives from low tonic dopamine (DA) levels and low phasic DA reactivity in subcortical neural structures implicated in appetitive responding. We note that different findings often emerge in neuroimaging studies when irritability is assessed in circumscribed diagnostic groups versus representative samples. We conclude with directions for future research, and propose that more authors use hierarchical Bayesian modeling, which captures functional dependencies between irritability and other dispositional traits (e.g., trait anxiety) that standard regression models are insensitive too. Treatment implications are also considered.