Only the first MCA dimension for each of the two variable sets showed substantial heritability, with this dimension of the “occur together” symptoms being more informative than the “ever occur” symptoms. Further, because the first MCA dimension for the “ever occur” symptoms did not vary among individuals with lifetime OD it did not help to differentiate the OD subtypes. On this basis, we chose to use the 15 “occur together” symptoms in the cluster analysis in conjunction with 54 previously selected variables (listed in Supplementary Tables 1 and 2). The MCA reduced the total 69 categorical variables to 10 continuous dimensions, explaining over 99% of the variance.
