Stimulant psychosis is a mental health condition that can happen when you take certain drugs, such as cocaine or amphetamines, for too long or in large amounts. When this happens, it can cause you to feel confused, have hallucinations, and behave strangely. It's like taking a pretend trip to another world where everything feels or looks different. It can make it hard for you to think straight and keep you from being able to act normally.