CD4 and major depressive disorder: These findings are in contrast with Coppenhagen, whose participants with a low CD4 count, particularly less than 50, were found to have a higher rate of depression.12 The literature reports that certain ARV drugs, such as efavirenz, may cause mood dysregulation, and although only four (17.4%) participants out of the 24 were on an efavirenz-based regimen, there was no statistical evidence to suggest that the major depression was a result of this drug.