Hello! I am trying to get some answers. My daughter has involuntary body shaking, like body jerking and jolting. It happens mostly when she is sitting down resting or lying on the couch resting. She has a under active thyroid as well as being recently diagnosed with PCOS. Dr. said PCOS can cause anxiety and she thinks it is the reason why she has been shaking. Now, let me be clear, this is not a tremor which might be a sign of anxiety. This is more like body jerking. Does anyone else out there experience this type of involuntary bodily movement?