Answer:
illusion
Step-by-step explanation:
Schizophrenia is defined as a mental disorder. People suffering from schizophrenia interprets the reality abnormally. It is a chronic disorder of the brain where people often interpret the wrongly what they see or feel. Schizophrenia may result in hallucination, wrongly interpreting things, false belief, confused thoughts, improper speech, etc.
In the context, a person suffering from schizophrenia claims that he has invented a drug or medicine that can cure every type of mental disorders. He is in a false belief of himself that he has invented a single treatment for all the mental disease. Hence his belief will be considered as an illusion of his due to his schizophrenia.