Dereistic refers to a type of thinking characterized by irrational or disconnected thoughts. Some synonyms for this word include delusional, fantastical, or hallucinatory thinking. Other similar terms include irrational, illogical, or unreasonable thought processes. It may also be described as fanciful, imaginary, or unfounded thinking. Some more informal synonyms might include crazy, wacky, or bonkers thinking. Regardless of how one refers to this type of thought, it is generally considered problematic and often indicative of a serious mental health condition. Treatment may involve therapy or medication to help manage symptoms and improve the individual's quality of life.