Yin Yang
It wasn’t until the early 1950s that bipolar disorder was fully recognized as a mental disorder of its own. Prior to that, bipolar disorder had always been confused with mental disorders like schizophrenia or psychosis. In bphope.com, it is stated that "German psychiatrist Karl Leonhard and colleagues initiated the classification system that led to the term “bipolar,” differentiating between unipolar and bipolar depression."