The psych evals vary so greatly. I am a psychologist and conduct bariatric assessments. Mine take about 2 hours and I do give the MMPI...it is actually very relevant to the situation as it can screen for psychosis, substance abuse, easting disorders, etc. It's really for the surgeons to protect them from potential liability. Meanwhile...as a patient, I had mine done on Friday and it was about half an hour. I pretty much told the psychologist what I wanted and needed and it was really quick.