https://en.wikipedia.org/wiki/Charles_Whitman
Investigating officers found that Whitman had visited several UT Austin physicians in the year before the shootings; they prescribed various medications for him. Whitman had seen a minimum of five doctors between the fall and winter of 1965 before he visited a psychiatrist from whom he received no prescription. At some other time he was prescribed Valium by Jan Cochrum, who recommended he visit the campus psychiatrist.[54]
Whitman met with Maurice Dean Heatly, the staff psychiatrist at the University of Texas Health Center, on March 29, 1966.[55] He referred to his visit with Heatly in his final suicide note, writing: "I talked with a Doctor once for about two hours and tried to convey to him my fears that I felt come [sic] overwhelming violent impulses. After one visit, I never saw the Doctor again, and since then have been fighting my mental turmoil alone, and seemingly to no avail."[43]
Heatly's notes on the visit said, "This massive, muscular youth seemed to be oozing with hostility [...] that something seemed to be happening to him and that he didn't seem to be himself."[56] "He readily admits having overwhelming periods of hostility with a very minimum of provocation. Repeated inquiries attempting to analyze his exact experiences were not too successful with the exception of his vivid reference to 'thinking about going up on the tower with a deer rifle and start shooting people.'"[57]
Autopsy
Although Whitman had been prescribed drugs and was in possession of Dexedrine at the time of his death, the toxicology was delayed because Whitman had been embalmed on August 1, after his body was brought to the Cook Funeral Home in Austin. However, an autopsy had been requested in the suicide notes left by Whitman and was then approved by his father.[58]
On August 2, an autopsy was conducted by Coleman de Chenar (a neuropathologist at Austin State Hospital) at the funeral home. Urine and blood were removed to test for traces of amphetamines or other substances.[59][60] During the autopsy, Chenar discovered a "pecan-sized" brain tumor,[61] which he labeled an astrocytoma and which exhibited a small amount of necrosis. These findings were later revised by the Connally Commission: "It is the opinion of the task force that the relationship between the brain tumor and Charles J. Whitman's actions on the last day of his life cannot be established with clarity."[62]
See that's an argument for background checks.