Towards the understanding of state-independent neural traits underlying psychiatric disorders

• The search for neural traits may provide insights into rudimentary changes underlying psychiatric disorders. • A neural trait captures invariant core pathology across different brain functional states and disease stages. • Cross-paradigm connectivity is shown to be a valid and reliable approach to assessing neural traits. • Increased connectivity in the cerebello-thalamo-cortical circuitry seems to be a potential neural trait for schizophrenia. Hampered by the symptom complexity and diversity, the understanding of fundamental mechanisms underlying psychiatric disorders remains elusive. Traditional neuroscience research focusing on each behavioral domain separately may lack an overarching view of the pathogenesis of an entire disorder, offering limited power to identify core neuropathology that could possibly account for the disorder’s various symptoms. The search for neural traits that are robustly present across different brain functional states and disease stages may provide insights into the rudimentary changes beneath manifest clinical phenotypes and thus help penetrate the causal mechanisms underlying a complex disorder. In this review, I briefly summarize previous research on this topic, emphasize how neural traits may help boost the understanding of biological mechanisms underlying psychiatric disorders, and exemplify how the observed traits may aid individualized predictions for diagnosis and prognosis in precision psychiatry, in particular related to schizophrenia. I also discuss a proposed research framework that can be leveraged for future studies on neural traits, as well as considerations for future applications of this nascent research strategy.