Kadinsky is the psychiatrist in the Northern Indiana State Hospital.
After Sam is injured in a car accident, he is admitted to Northern Indiana State Hospital where Dr Kadinsky diagnoses him as suffering from a psychotic episode.
When Dean arrives, Kadinsky informs him of Sam's condition and leads him to Sam's room. He admits that Sam's inability to sleep despite being given medication is both worrying and unheard of.
During a check up on Sam, Kadinsky considers surgery as a solution. Sam's hallucination of Lucifer briefly takes on his form to scare Sam.
Sam eventually leaves after being healed by Castiel, who then takes his place in the hospital. Kadinsky is shown interviewing and accepting a new nurse - Meg.