Polymorph forms of (2S)-(4E)-N-methyl-5-[3-(5-isopropoxypyridin)yl]-4-penten-2-amine p-hydroxybenzoate, and methods for their preparation, pharmaceuticalcomposition containing said polymorph(s) and use, are disclosed. The polymorphscan be administered to patients susceptible to or suffering from conditionsand disorders, such as central nervous system disorders, to treat and/or preventsuch disorders.