Who brings up the possibility that Jamey's current mental state could be due to drugs?

After learning about Jamey's current mental state, Souza brings up the possibility of drugs being a link to Jamey's mental state. Alex does not believe Jamey takes drugs. Dr. Flowers saw no signs of drug use when she worked with Jamey. Dr. Mainwaring also does not think Jamey is on drugs, but instead thinks that Jamey is definitely schizophrenic. While everyone is doubtful that Jamey is on drugs, Souza believes it's a possibility that Digby could have given Jamey drugs without Jamey knowing.