When someone goes psycho, it means they become extremely emotional or irrational in an uncontrollable manner. Here are some synonyms that can be used instead of "went psycho": lost it, went crazy, flew off the handle, had a breakdown, had a meltdown, had a fit, had a freak-out, went bonkers, flipped out, became unhinged. These descriptors all suggest a sudden and drastic change in behavior, often characterized by a lack of self-control or rational thinking. It's important to remember that using these terms to describe someone's behavior can be insensitive and stigmatizing to those dealing with mental health challenges.