Comparison of cognitive dysfunction between schizophrenia and bipolar

I already knew that, I read a study done by the World Health Organization. It lists diseases by disability level. Top is severe depression bcz of suicide, Alzheimer and dementia, complete paralysis and then schizophrenia. Schizophrenia ranked worst mental disease overall and 4th most disabling disease, more than mental disability and blindness or waist-down paralysis.