This case has been an education. I had no idea that this severe a set of symptoms could result from un- or undertreated hyperthyroid. It often seems that practically everyone I know of my age has hypothyroid, and we often complain of the constant related fatigue. I suppose it's better than the alternative.
I wonder if Erin was being treated for hyperthyroid, and if so was her family aware and is that why they were so frantic about her confusion and then her disappearance. It seems like something police/first responders should have knowledge of as a true medical emergency, along with diabetes and other metabolic crises, so that when a subject is reported to be confused and behaving in an erratic manner that is unprecedented for them, they don't first go down the path of illicit substance intoxication anyway. (I'm not trying to read local LE's minds in this matter, but it's where the thoughts of posters on this thread turned as well ... how wrong we were.)
Rest in peace, Erin. The world is going to miss your vibrant spirit and the contributions you could have made to high tech and the AI field.
edited for coherence