A 34-year-old male presents with a 6-year history of auditory hallucinations and persecutory delusions. Over the past 3 months, he has developed pervasive depressed mood, anhedonia, insomnia, and feelings of worthlessness that meet full criteria for a major depressive episode. His treatment team notes that during a 2-year period early in his illness, he experienced continuous psychotic symptoms without any mood episodes. His mother confirms that his hallucinations and delusions have been present during times when his mood was stable. Which diagnostic conclusion is most consistent with this presentation?