There is a small cemetery located on what was the grounds of the St. State Hospital no. 2 at 36th and Frederick
Ave in St. Joseph Mo. The graves are only identified by numbers.The buildings there are now occupied by a state prison and the mental hospital and all of it's records have moved across the street. It is now called the North West Mo. Psychiatric Rebab. Center. Sadly it now treats mostly forensic patients and many of the area's chronic mental patients are without adequate treatment. Any records that are left from the cemetery and from early hospital patients would have to be obtained from the medical records department of that hospital.The address is 3505 Frederick Avenue, St. Joseph, Mo. 64506.
There is a North West Mo. Genealogy Center at 412 Felix, St. Joseph, Mo. 64501 where a lot of old records are held. I do recall seeing a census from 1900 listing St. State Hospital patients there. Remember in very early years the hospital was called the State Lunatic Asylum No. 2.
Good luck with your search.