AbstractBackgroundA systematic overview of underlying mechanisms in the new disruptive mood dysregulation disorder (DMDD) diagnosis is needed. The Research Domain Criteria (RDoC) represent a system of six domains of human functioning, which aims to structure the understanding of the nature of mental illnesses. By means of the RDoC framework, the objective of this systematic review is to synthesize available data on children and youths <18 years suffering from DMDD as reported in peer reviewed papers.MethodsA literature search guided by PRISMA was conducted using Medline, PsychInfo, and Embase, while the RDoC domains were employed to systematize research findings. Risk of bias in the included studies was examined.ResultsWe identified 319 studies. After study selection, we included 29 studies. Twenty‐one of these had findings relating to >1 RDoC domain. The risk of bias assessment shows limitations in the research foundation of current knowledge on mechanisms of DMDD.DiscussionReviewing self‐report, behavior and neurocircuit findings by means of RDoC domains, we suggest that DMDD youths have a negative interpretation bias in social processes and valence systems. In occurrence of a negative stimuli interpretation, aberrant cognitive processing may arise. However, current knowledge of DMDD is influenced by lack of sample diversity and open science practices.ConclusionWe found the six RDoC domains useful in structuring current evidence of the underlying mechanisms of DMDD. Important opportunities for future studies in this field of research are suggested. In clinical practice, this comprehensive summary on DMDD mechanisms can be used in psychoeducation and treatment plans.