We Had A Horrible Family Experience....my 12 Year Old Granddaughter

We had a horrible family experience....my 12 year old Granddaughter told us she was taking medication because she was depressed, had anxiety and add.she came for the night and was going home the next night and we did not know she had her meds with her...she is a normally happy, affectionate child but we saw a huge difference in her....and had not seen her for one year.... I she was visiting her dad, my son and I was not told she was on medication when she came to stay at my house overnight......She told us later that night before bed. ......we mistakenly thought she would tbe given her medication the next day at her fathers....and never dreamed she had control and possession of these medications....she slept most of the evening and I could not get her up the next morning...and she would not eat or engage with us ....we were unaware that before getting her home she took all of her meds together because she had called her mother who directed her to do so...... and within an hour had what I can only describe as some sort of psychotic event.....she began running through the house , screaming, cursing and thrashing around the floor.... she was impossible to console and actually struck me ...she called the police and just flipped out entirely....We we’re finally able to calm her down after about 2 hours ....the told her that they would take her to a juvenile center.. We have always been very close and she has always been a kind child....... a pediatrician in Connecticut had prescribed these dangerous drugs and sent her way to Pennsylvania for Christmas within 2 days... notbtracking her....ignoring her history of sexual abuse at an early age by a cousin which her mother defended the cousin...and blaming our family for getting involved to keep this boy from her......this caused a huge family rift and instead of addressing the remnants of all this with proper counseling , the drugs were given. We were horrified at this approach ....contraindicated in anyone under25... she told me something horrible had happened to her and new the mantra “ I have chemical balance in my brain and I need SSRIs for the rest of my life”.......despite this being disproven in all current literature...... We were never told what happened to her as her mother came for her...my son has lost contact. This is our family tragedy...these are inappropriate and dangerous drugs for an adolescent .....completely dangerous and her emotional problem goes unaddressed we can only surmise...we are convinced that the horror we saw was drug induced....it looked like something out of the exorcist..