Why GPT-4o's sudden shutdown left people grieving

OpenAI's decision to replace 4o with the more straightforward GPT-5 follows a steady drumbeat of news about the potentially harmful effects of extensive chatbot use. Reports of incidents in which ChatGPT sparked psychosis in users have been everywhere for the past few months, and in a blog post last week, OpenAI acknowledged 4o's failure to recognize when users were experiencing delusions. The company's internal evaluations indicate that GPT-5 blindly affirms users much less than 4o did. AI companionship is new, and there's still a great deal of uncertainty about how it affects people. Yet the experts we consulted warned that while emotionally intense relationships with large language models may or may not be harmful, ripping those models away with no warning almost certainly is.