An osmotic device having a unitary core surrounded by a semipermeable membrane having at least one passageway there through, wherein: a) the unitary core comprises a mixture of amantadine salt, osmotic salt, and at least one other pharmaceutically acceptable excipient; b) the osmotic salt is not coated with a release rate controlling coating; c) the permeability of the semipermeable membrane is adapted to cooperate with the osmotic salt to control the release profile of amantadine salt from the osmotic device; d) the amantadine salt and osmotic salt have an ion in common, wherein the amantadine salt is amantadine hydrochloride and the osmotic salt is sodium chloride; e) amantadine salt is released through the one or more passageways according to a sigmoidal controlled release profile, optionally wherein release of amantadine salt is delayed for a period of time, when the osmotic device is exposed to an aqueous environment of use; f) the weight ratio of amantadine salt to osmotic salt ranges from 4:1 to 30:1, the semipermeable membrane comprises a cellulose acetate grade 1 and a cellulose acetate grade 2, wherein the weight ratio of a cellulose acetate grade 1 to the total amount of cellulose acetates is from 0.3:1 to 0.7:1, and the osmotic device provides a sigmoidal release profile of amantadine salt; g) the cellulose acetates comprise a cellulose acetate grade 1 having 7 - 10 % by weight of hydroxyl groups, 30-36 % by weight of acetyl groups, and a viscosity of 200 -280 seconds, and a cellulose acetate grade 2 having 3 - 5 % by weight of hydroxyl groups, 37-43 % by weight of acetyl groups, and a viscosity of 6.0 - 45.0 seconds, said viscosities being determined as set forth in methods ASTM D817 (Formula A) and ASTM D1343; and h) the unitary core comprises less than 6 % of NaCl w/w, based upon the weight of the uncoated core, and the semipermeable membrane comprises more than 25 % w/w of cellulose acetate grade 1, based upon the weight of the semipermeable membrane. a) the unitary core comprises a mixture of amantadine salt, osmotic salt, and at least one other pharmaceutically acceptable excipient; b) the osmotic salt is not coated with a release rate controlling coating; c) the permeability of the semipermeable membrane is adapted to cooperate with the osmotic salt to control the release profile of amantadine salt from the osmotic device; d) the amantadine salt and osmotic salt have an ion in common, wherein the amantadine salt is amantadine hydrochloride and the osmotic salt is sodium chloride; e) amantadine salt is released through the one or more passageways according to a sigmoidal controlled release profile, optionally wherein release of amantadine salt is delayed for a period of time, when the osmotic device is exposed to an aqueous environment of use; f) the weight ratio of amantadine salt to osmotic salt ranges from 4:1 to 30:1, the semipermeable membrane comprises a cellulose acetate grade 1 and a cellulose acetate grade 2, wherein the weight ratio of a cellulose acetate grade 1 to the total amount of cellulose acetates is from 0.3:1 to 0.7:1, and the osmotic device provides a sigmoidal release profile of amantadine salt; g) the cellulose acetates comprise a cellulose acetate grade 1 having 7 - 10 % by weight of hydroxyl groups, 30-36 % by weight of acetyl groups, and a viscosity of 200 -280 seconds, and a cellulose acetate grade 2 having 3 - 5 % by weight of hydroxyl groups, 37-43 % by weight of acetyl groups, and a viscosity of 6.0 - 45.0 seconds, said viscosities being determined as set forth in methods ASTM D817 (Formula A) and ASTM D1343; and h) the unitary core comprises less than 6 % of NaCl w/w, based upon the weight of the uncoated core, and the semipermeable membrane comprises more than 25 % w/w of cellulose acetate grade 1, based upon the weight of the semipermeable membrane.