Hello- Thank you for asking the question here at JustAnswer. I have read what you have written and am happy to respond.
This is obviously a very upsetting situation that is occurring with your grand-daughter and after reading what you have written, it is clear that she is having significant behavioral problems as well as psychological in that she has been taking pills etc. This is beyond the point of pushing the boundaries however, it doesn't appear that she is suffering from a serious psychiatric disorder that cannot be reversed.
She does need to be evaluated by a child psychologist as soon as possible, and if possible I would do so sooner than later in wait of the health system.
I am providing you a link to the British Psychological Association. You can click on the FIND A PSYCHOLOGIST Tab at the right to find Child Psychologists in your geographic area. I would schedule an appointment as soon as possible.
Here is a helpful link that helps to understand what may be going on: http://www.aacap.org/cs/root/facts_for_families/children_with_oppositional_defiant_disorder
I wish you the best at this difficult time. Please feel free to reply as necessary.
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