Captain James Sawyer (David Warner) was suffering from paranoid schizophrenia, constantly suspecting plots to undermine his authority and awarding irrational and arbitrary punishments to his officers. Hornblower also mentions that Captain Sawyer had often battled death and danger, and was paying the price, meaning that he had been under a great deal of stress throughout his life, and his mind was exhausted and a stress induced illness was sustained as a result. On top of this, the doctor was drugging him, so this could have aided in his mind concocting stories and his overall paranoia.