A 24-year-old man from Delhi presents to the psychiatric outpatient department with a 6-month history of hearing voices commenting on his actions and arguing with each other. His family reports he has become increasingly withdrawn, neglects personal hygiene, and speaks in a flat, monotonous tone. He denies any substance use or recent head injury. On mental status examination, he is oriented to person, place, and time, but his thought process is disorganized. He reports that his thoughts are being broadcast to others and that neighbors are conspiring against him. What is the most likely diagnosis?