My mom just started taking Risperdal yesterday....What should I be seeing the day after her first dosage?

Her neurologist prescribed her a low dose of 0.5mg twice daily. Her first day of use was yesterday. After having to endure intense episodes of paranoia and anxiety.....it was becoming very difficult to deal with mom. Yesterday was her first dose and she immediately had a 360 degree turn around. However... last night the paranoia returned and today she is very lethargic... drowsy with slow movements and having problems following directions and her gaite is very slow..... She is also experiencing weakness in her limbs... Is this common after just one dose.....Please Help!