What Causes Anxiety And Confusion In An Elderly?

My 84 yr old mother has non alcohol cirrhosis and is on daily lactolos medicine among others. She is experiencing encephalopathy , confusion, anxiety and fear, sleepless nights. Doctors recently prescribed 300 mg gabapenta for leg pain and she was completely out of touch, cut this back to 100mg and she is doing better, but has sudden moods, and falls suddenly into these confused states. Could this gabapenta be the cause?