What do systematic reviews say?

Memantine vs placebo

Memantine showed no clear difference in efficacy: number of participants who respond to treatment ‐ at 3… compared with placebo (low certainty).

• Ketamine and other glutamate receptor modulators for depression in adults with bipolar disorder 2021 · Cochrane Headline outcomes only
  OR 1.66 [0.69, 4.03]
  2 studies · 261 participants
  Low