Dear Welcome to HM We understnd your concerns I went through your details. I suggest you not to worry much. I sincerely opine that these psychological mannerisms never requires any medicines. But the details you provided here are not enough to give a correct diagnosis. Your niece could be hyper active. That is one possibility. Second possibility is that she is experiencing mood swings due to non-clinical depression or disappointment. Please describe the whole problem detail and post a direct question to me. I shall definitely help you with psychotherapy techniques to over come obsessive thoughts. Hope this answers your query. Available for further clarifications. Good luck.