The succinate and napadisylate salts and solvates of 2-(Methyloxy)-N-[2-methyl-1-phenyl-2-(1-pyrrolidinyl)propyl]-4,6-bis(trif- luoromethyl)benzamide, 6-bis(trifluoromethy)benzamide napadisylate, and uses thereof in the treatment of disorders relating to GlyT1 transporter, such as schizophrenia, are disclosed.