The present invention provides an immediate release oral dosage form comprising therapeutically effective amount of vilazodone or a salt thereof and at least one excipient. The dosage form includes 10 to 40 mg of vilazodone or a salt thereof, and is compressed in a tablet formulation. The tablet comprising 40 mg vilazodone or a salt thereof has a hardness of more than 9 kp and less than or equal to 14 kp. The tablet comprising 20 mg vilazodone or a salt thereof has a hardness of more than 8 kp and less than or equal to 12 kp, and the tablet comprising 10 mg vilazodone or a salt thereof has a hardness of more than 6 kp and less than or equal to 9 kp.
