The present invention relates to crystalline forms of cis-(E)-4-(3-Fluorophenyl)-2&prime,3&prime,4&prime,9&prime-tetrahydro-N,N-dimethyl-2&prime-(1-oxo-3-phenyl-2-propenyl)-spiro[cyclohexane-1,1&prime[1H]-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.