Answer:
Delusions of reference.
Step-by-step explanation:
Delusions of reference can be defined as a delusional perception, conviction or belief an individual has that irrelevant, mundane, innocuous and unrelated events in the world are having a great level of personal significance or directly has an impact on them, even though it's unreal.
In psychology, delusions of reference are also known as ideas of reference and it typically refers to an individual having a belief (perception) that certain external stimuli from their environment are referencing or directly impacting them whereas it's untrue or unreal. It is considered to be a sign of mental or psychotic illness e.g schizophrenia.
In this scenario, Leonardo believes that his favorite TV show is giving him a coded message and that the main character speaks directly and personally to him. As a result, he decides to go to the filming location to talk to the main character. Thus, Leonardo is suffering from delusions of reference.