What Causes Severe Pain In Joints Of Arms And Legs While On Latuda?

My daughter, 39 years old, was put on Lamectil and a couple weeks later Latuda was added, as we have had a lot of family pain, meaning death of family members. She has anxiety attacks pretty bad. About nine days after starting Latuda, she woke up with severe joint pain in arms and legs and feet to the point she can hardly walk, she has a hard time moving her fingers or even lifting, is continually crying. Her doctor said to stop the Latuda. I am a retired nurse but at a lost what to do. We have had her to the ER, and they referred her on to a rheutmatologist, MRI of neck ok, and they are not sure what to do. My question is could the Latuda or Lamectil be a cause and, if so, will it go away or do you have any suggestions?