I have thought about this many times. I don't like to scrutinize mug shots too often because you never do know what goes on. Her poker face doesn't look high or mentally ill or anything of the sort. It looks like she cannot give one s*** about her situation.
I agree with you that I don't like to scrutinize mug shots. If I didn't know what this photo was, I could think it was:
a person after visiting her parent with alzheimers
a patient first waking up from colonoscopy "twilight" meds
someone waiting in the emergency room with a roto stomach virus
someone sitting in the courtroom waiting for a jury verdict
someone who is nauseous on a very bumpy ride
I think we often tend to see what we expect to see in a photo like this, and that can be unreliable.