An isolated antibody or a binding fragment thereof, which binds to aripiprazole comprising: a) a light chain CDR1 sequence comprising amino acid residues 46 to 55 of SEQ ID NO:43; a light chain CDR2 sequence comprising amino acid residues 71 to 77 of SEQ ID NO:43; a light chain CDR3 sequence comprising amino acid residues 110 to 118 of SEQ ID NO:43; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:44; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:44; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 125 of SEQ ID NO:44; b) a light chain CDR1 sequence comprising amino acid residues 44 to 54 of SEQ ID NO:47; a light chain CDR2 sequence comprising amino acid residues 70 to 76 of SEQ ID NO:47; a light chain CDR3 sequence comprising amino acid residues 109 to 117 of SEQ ID NO:47; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:48; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:48; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 126 of SEQ ID NO:48; c) a light chain CDR1 sequence comprising amino acid residues 44 to 58 of SEQ ID NO:51; a light chain CDR2 sequence comprising amino acid residues 74 to 80 of SEQ ID NO:51; a light chain CDR3 sequence comprising amino acid residues 113 to 121 of SEQ ID NO:51; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:52; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:52; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 130 of SEQ ID NO:52; or d) a light chain CDR1 sequence comprising amino acid residues 44 to 54 of SEQ ID NO:55; a light chain CDR2 sequence comprising amino acid residues 70 to 76 of SEQ ID NO:55; a light chain CDR3 sequence comprising amino acid residues 109 to 117 of SEQ ID NO:55; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:56; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:56; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 122 of SEQ ID NO:56. a) a light chain CDR1 sequence comprising amino acid residues 46 to 55 of SEQ ID NO:43; a light chain CDR2 sequence comprising amino acid residues 71 to 77 of SEQ ID NO:43; a light chain CDR3 sequence comprising amino acid residues 110 to 118 of SEQ ID NO:43; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:44; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:44; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 125 of SEQ ID NO:44; b) a light chain CDR1 sequence comprising amino acid residues 44 to 54 of SEQ ID NO:47; a light chain CDR2 sequence comprising amino acid residues 70 to 76 of SEQ ID NO:47; a light chain CDR3 sequence comprising amino acid residues 109 to 117 of SEQ ID NO:47; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:48; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:48; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 126 of SEQ ID NO:48; c) a light chain CDR1 sequence comprising amino acid residues 44 to 58 of SEQ ID NO:51; a light chain CDR2 sequence comprising amino acid residues 74 to 80 of SEQ ID NO:51; a light chain CDR3 sequence comprising amino acid residues 113 to 121 of SEQ ID NO:51; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:52; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:52; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 130 of SEQ ID NO:52; or d) a light chain CDR1 sequence comprising amino acid residues 44 to 54 of SEQ ID NO:55; a light chain CDR2 sequence comprising amino acid residues 70 to 76 of SEQ ID NO:55; a light chain CDR3 sequence comprising amino acid residues 109 to 117 of SEQ ID NO:55; a heavy chain CDR1 sequence comprising amino acid residues 45 to 54 of SEQ ID NO:56; a heavy chain CDR2 sequence comprising amino acid residues 69 to 85 of SEQ ID NO:56; and a heavy chain CDR3 sequence comprising amino acid residues 118 to 122 of SEQ ID NO:56.