CSF levels of MIP-1β and MCP-1 have been reported lower among 15 patients with depression who had recently attempted suicide compared to 43 healthy controls [36], whereas a small study investigating CSF MCP-1 levels among 11 patients with depression compared to 27 healthy controls found no significant difference, however, this study was likely underpowered to identify contrasts [37]. This evidence concerns the gene CCL4 and depressive symptom measurement.