The present invention relates to crystalline brexpiprazole having a particle size distribution (PSD) characterized by a d(90) of 30 μm to 100 μm, by a d(10) of at least 1.0 μm, and by a d(4,3) of at least 15.0 μm. The present invention also relates to a pharmaceutical composition comprising a crystalline brexpiprazole having a PSD characterized by a d(90) of 30 μm to 100 μm, by a d(10) of at least 1.0 μm, and by a d(4,3) of at least 15.0 μm, and to an aqueous suspension comprising said crystalline brexpiprazole. The present invention also relates to a composition comprising a crystalline brexpiprazole having a PSD characterized by a d(90) of 30 μm to 100 μm, by a d(10) of at least 1.0 μm, and by a d(4,3) of at least 15.0 μm, wherein said composition is essentially free from secondary particles of brexpiprazole. The present invention also relates to an injectable preparation, vial, prefilled syringe, or kit, comprising crystalline brexpiprazole having a PSD characterized by a d(90) of 30 μm to 100 μm, by a d(10) of at least 1.0 μm, and by a d(4,3) of at least 15.0 μm. The present invention also relates to a process for the preparation of an aqueous suspension, a vial, a prefilled syringe, or a lyophilisate, comprising a step of incorporating crystalline brexpiprazole having a PSD characterized by a d(90) of 30 μm to 100 μm, by a d(10) of at least 1.0 μm, and by a d(4,3) of at least 15.0 μm. Finally, the present invention also relates to crystalline brexpiprazole having a PSD characterized by a d(90) of 30 μm to 100 μm, by a d(10) of at least 1.0 μm, and by a d(4,3) of at least 15.0 μm, for use in the treatment or prevention of relapse of schizophrenia, bipolar disorder, or depression.