A few were present in isolation (eg, all females in one cluster and all males in one cluster, no current use of insulin in one cluster, pregabalin monotherapy in two clusters but completely absent in one cluster, prior use of gabapentin in one cluster but completely absent in two clusters, past or current medical history of depression in one cluster but completely absent in three clusters), but they were found in various proportions in the remaining clusters. This evidence concerns the gene INS and major depressive disorder.