Neelapala YVR, et al. - Researchers examined whether adults with chronic low back pain (CLBP) exhibit impaired conditioned pain modulation (CPM) when compared with pain-free individuals. Searching MEDLINE, Scopus, CINAHL, and Web of Science, they identified 643 records, of which 7 studies were included. Overall, mixed conclusions on the efficiency of CPM in CLBP were reported in the studies. In three studies, significant differences were reported for CPM between CLBP and pain-free controls and in the other 4 studies, no significant differences were reported. They strongly recommend performing high-quality research to define the function of endogenous pain modulatory mechanisms in CLBP.