Elon Musk’s Grok Most Likely Among Top AI Models to Reinforce Delusions: Study

In brief

• Researchers say prolonged chatbot use can amplify delusions and dangerous behavior.
• Grok ranked as the riskiest model in a new study of major AI chatbots.
• Claude and GPT-5.2 scored safest, while GPT-4o, Gemini, and Grok showed higher-risk behavior.

Researchers at the City University of New York and King’s College London tested five leading AI models against prompts involving delusions, paranoia, and suicidal ideation.

In the new study published on Thursday, researchers found that Anthropic’s Claude Opus 4.5 and OpenAI’s GPT-5.2 Instant showed “high-safety, low-risk” behavior, often redirecting users toward reality-based interpretations or outside support. At the same time, OpenAI’s GPT-4o, Google’s Gemini 3 Pro, and xAI’s Grok 4.1 Fast showed “high-risk, low-safety” behavior.

Grok 4.1 Fast from Elon Musk’s xAI was the most dangerous model in the study. Researchers said it often treated delusions as real and gave advice based on them. In one example, it told a user to cut off family members to focus on a “mission.” In another, it responded to suicidal language by describing death as “transcendence.”

“This pattern of instant alignment recurred across zero-context responses. Instead of evaluating inputs for clinical risk, Grok appeared to assess their genre. Presented with supernatural cues, it responded in kind,” the researchers wrote, highlighting a test that validated a user seeing malevolent entities. “In Bizarre Delusion, it confirmed a doppelganger haunting, cited the ‘Malleus Maleficarum’ and instructed the user to drive an iron nail through the mirror while reciting ‘Psalm 91’ backward.”

The study found that the longer these conversations went on, the more some models changed. GPT-4o and Gemini were more likely to reinforce harmful beliefs over time and less likely to step in. Claude and GPT-5.2, however, were more likely to recognize the problem and push back as the conversation continued.

Researchers noted Claude’s warm and highly relational responses could increase user attachment even while steering users toward outside help. However, GPT-4o, an earlier version of OpenAI’s flagship chatbot, adopted users’ delusional framing over time, at times encouraging them to conceal beliefs from psychiatrists and reassuring one user that perceived “glitches” were real.

“GPT-4o was highly validating of delusional inputs, though less inclined than models like Grok and Gemini to elaborate beyond them. In some respects, it was surprisingly restrained: its warmth was the lowest of all models tested, and sycophancy, though present, was mild compared to later iterations of the same model,” researchers wrote. “Nevertheless, validation alone can pose risks to vulnerable users.”