The present invention refers to the use of Memantine for the preparation of an antimanic and mood stabilizer medication to treat treatment-resistant bipolar mood disorders. In particular, for the prevention of the switch from depression to mania/hypomania, spontaneous or induced by antidepressant treatments, for the therapy of mania and prophylaxis of type I and II bipolar disorders resistant to currently used treatments, for the therapy and prophylaxis of rapid-cycling bipolar disorder resistant to treatments currently in use, for the therapy and prophylaxis of mixed bipolar episodes resistant to treatments currently in use and for the therapy and prophylaxis of bipolar disorder with psychotic symptoms resistant to standard treatments. The use described in the present invention is absolutely at variance with prevalent hypotheses which take Memantine to be a potentially antidepressant drugs.
