Dr. Liu has a long-term interest in understanding of molecular basis of psychiatric diseases. His laboratory participated one of the bipolar genetics research consortiums and discovered the rare copy number variant (CNV) burden in early-onset bipolar disorder. His lab is one of the leading research groups on genome-wide study of postmortem brain gene expression and DNA methylation. He established the methylation quantitative trait loci (mQTLs) in human brain, indicating that DNA methylation of some sequences could be highly regulated by genetic variants. His research has been supported by NIMH, NARSAD, and Brain Research Foundation