The present invention relates to crystalline forms of cis-(E)-4-(3-Fluorophenyl)-2',3',4',9'- tetrahydro-N,N-dimethyl-2'-(1-oxo-3-phenyl-2-propenyl)-spiro[cyclohexane-1, 1 '[1 H]- pyrido[3,4-b]indol]-4-amine, pharmaceutical compositions and medicaments comprising these modifications, the use of these modifications as well as to a process for making the crystalline forms.