The present invention relates to a composition comprising N-[4-[4-(1,2-benzisothiazol-3-yl)-1-piperazinyl]-(2R,3R)-2,3-tetramethylene-butyl]-(1′R,2′S,3′R,4′S)-2,3-bicyclo[2,2,1]heptanedicarboximide or a pharmaceutically acceptable acid addition salt thereof. In detail, the composition relates to a sustained release formulation for injection which maintains an effective blood level of the above-mentioned compound.
