Disclosed are polymeric forms of N-[4-(trifluoromethyl)benzyl]-4-methoxybutyramide of Formula (I) having the following peaks at the diffraction degrees (2-theta) in the X-ray powder diffraction pattern plus or minus 0.2: 9.7 12.0 18.0 24.1 25.9. Also disclosed is polymeric form B having the following peaks at the diffraction degrees (2-theta) in the X-ray powder diffraction pattern plus or minus 0.2: 11.7 19.8 22.3 23.6. Further disclosed is the process for making polymorphic forms A and B, a pharmaceutical composition comprising polymorphs A or B and the use of the Forms A and B in the manufacture of a medicament for treating drug addiction and alcoholism and reducing the voluntary consumption of ethyl alcohol in the treatment of abstinences syndrome.
