The man had been trying to get into the Power Station.
The first patient was brought to the facility by police who had picked him up near Koeberg Power station on 7 January 2019.
The police officials asked him why he was trying to jump the fence and noticed he was talking to himself and laughing inappropriately.
They took the man to New Somerset Hospital where he was under observation for 72 hours to determine whether he had a mental health issue.
The patient was referred to Valkenberg on 14 January.
In the second case, a man was found wandering the streets, confused and unable to make sense when engaged in conversation.
The patient was picked up by SAPS officials on 30 November 2018 near the N7 highway close to Atlantis.
The man was unable to give police any personal information and he was taken to Wesfleur Hospital for observation.
At Valkenberg, staff managed to get a name, Linduyise Patrick Madunha, and address in Langa from him.
However, when social workers took the patient to the address last month, nobody recognised him.
There is also doubt that he gave his real name.
Anyone with information about these two men contact the social worker Nico Benting on 021 826 5849 or 021 440 3190.