When we say that someone has something "on the brain," we mean that it's the only thing they can think about. However, this phrase can get repetitive and lose its impact if overused. To shake things up, we can use various synonyms for "have on the brain," such as "stuck in your head," "obsessed with," "haunted by," "fixated on," "preoccupied with," "consumed by," or "unable to shake off." Using different synonyms can help you express yourself more effectively and creatively, especially when trying to convey a particular emotion or feeling. So next time, when you wanna mix it up and make your writing more engaging, try using some of these synonyms instead of "have on the brain".