A PMHNP is deployed to a community shelter following a devastating tornado. Among the survivors, the PMHNP must conduct rapid mental health triage to identify individuals requiring immediate psychiatric intervention. A 45-year-old male survivor who lost his home sits quietly in the corner, staring blankly. He does not respond to verbal prompts, does not track movement with his eyes, and has not eaten or consumed water in over 18 hours despite available resources. Staff report he has not spoken since arriving at the shelter 12 hours ago. His vital signs are stable. Which triage assessment finding most clearly indicates the need for immediate psychiatric intervention rather than supportive monitoring?