Fig. 2

Rmcorr plot depicting within-person associations across admission and discharge between body mass index and scores of the Obsessive–Compulsive Inventory–Revised. Note that, in rmcorr, separate parallel lines are fit to the data from each person and the sign of the rmcorr coefficient is indicated by the direction of the common regression slope. In the rmcorr plot, each patient’s data and corresponding line are shown in different color. This is done because rmcorr can capture strong intra-individual relationships (here: between body weight and obsessive–compulsive symptoms across the two measurement time points) that are missed by using averaged data. As can be seen by the negative rmcorr coefficient (r_rm =  − .27) and the negative slopes of the individual fit lines, larger weight gain was associated with decreases in obsessive–compulsive symptoms