The present invention is directed to a novel crystalline form of (2S)-(-)-N-(6-chloro-2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl)-sulfamide, pharmaceutical compositions containing said crystalline form and the use of said crystalline form in the treatment of anxiety and related disorders; bipolar depression and mania; depression; epilepsy and related disorders; epileptogenesis; glucose related disorders; lipid related disorders; migraine; obesity; pain; substance abuse; or for neuroprotection. The present invention is further directed to a process for the preparation of the novel crystalline form.