Eugen Bleuler was an early 20th century Swiss psychiatrist who studied schizophrenia and other mental disorders. He coined the term "autism" to describe behaviors he observed in some schizophrenia patients, including self-absorption, preference for solitude, one-sided conversations, and lack of empathy. Bleuler noted that some children exhibited autistic behaviors without developing schizophrenia, helping distinguish autism as its own condition.