Final answer:
Mel exhibits signs of paranoid psychosis, which is characterized by persistent delusions of persecution or conspiracy. His condition differs from schizophrenia, which is a broader mental disorder with a diverse array of symptoms, although both may involve delusions.
Step-by-step explanation:
Based on the symptoms described in the question, where Mel believes that people are spying on him and plotting against him, and interprets mundane events like a stranger asking for directions or static on a phone call as evidence of these paranoid delusions, it is most likely that Mel is suffering from paranoid psychosis. Paranoid psychosis is characterized by these types of delusions, where a person has a persistent feeling of being persecuted or conspired against. It's important to note that while these symptoms can also occur in schizophrenia, paranoid psychosis is a more specific term relating to the type of delusions.
Schizophrenia, on the other hand, is a more general and severe mental disorder that involves a wide range of symptoms, including hallucinations, disorganized thinking, and negative symptoms such as emotional flattening and loss of pleasure. Treatment for psychosis typically requires antipsychotic medications that block dopamine receptors, which can diminish the intensity of delusions and hallucinations.