Participants receiving memantine did not show a statistically or clinically significant change in MADRS scores compared to placebo , either over the entire study ( = @ , favoring placebo , P = @ ) or at study completion ( week @ mean -LSB- SD -RSB- MADRS score change = -@ -LSB- @ -RSB- -LSB- memantine -RSB- ; -@ -LSB- @ -RSB- -LSB- placebo -RSB- ; P = @ ) .