Ann: ACW updated depression trial results and implications, page-34

Genuine question... Why would they have to ask them to stop? My understand for continued efficacy trials they would recruit patients without regular medications - newly diagnosed, or those that have struggled with finding the 'right' antidepressant. And I would think the point of comparison is to reduce confounders, and to gauge accurate response to therapy. Moreover, to prevent having side-effects in the combination group from tarring the 'safety profile' when contrast of the mono group would help to demonstrate it isn't their drug.