From an article it appears that it wasn't voluntary.
They must not have had access to his poetry or scripts.On Dec. 13, 2005, a magistrate ordered Cho to undergo an evaluation at Carilion St. Albans, a private psychiatric hospital. The magistrate signed the order after an initial evaluation found probable cause that Cho was a danger to himself or others as a result of mental illness.
The next day, according to court records, doctors at Carilion conducted further examination and a special justice, Paul M. Barnett, approved outpatient treatment.
A medical examination conducted Dec. 14 found that that Cho's "affect is flat. ... He denies suicidal ideations. He does not acknowledge symptoms of a thought disorder. His insight and judgment are normal."
The court papers indicate that Barnett checked a box that said Cho "presents an imminent danger to himself as a result of mental illness." Barnett did not check the box that would indicate a danger to others.