There is apparently proof that she became this drunk in less than an hour based on photos taken of her before, which makes it highly likely that she was given a drug, imo.
Now that it is pretty easy to retrieve meta data off of pictures, it’s pretty easy to create a timeline.
It wouldn't surprise me to find she was drugged, it's seemingly likely that was the case. Unfortunately, we'll never know for certain unless someone confesses to drugging her.