Does this lady have any family??? If so, shouldn't someone contact them so they are informed of her behavior so they can take her to a doctor? This poor soul sounds like she needs someone to help her, maybe get on some medication or get her into a facility that would be appropriate for her illness. I'm sure the other tenants of the building are really upset by her behavior but also probably don't know how to handle the situation.
Hope someone there will step in and take charge.