The present invention relates to a combination of pure 5-HT6 receptor antagonist, acetylcholinesterase inhibitor and NMDA receptor antagonist. Also, the present invention provides pure 5-HT6 receptor (5-HT6R) antagonists, or the pharmaceutically acceptable salt(s) thereof in combination with or as adjunct to acetylcholinesterase inhibitor and N- Methyl-D-aspartate (NMDA) receptor antagonist and their use in the treatment of cognitive disorders. The present invention further provides the pharmaceutical composition containing the said combination.
