I frequently hear of people who are diagnosed with "bipolar disorder and schizophrenia." This makes me wonder whether doctors say this because the term "schizoaffective disorder" is too complicated for people to understand.
Schizoaffective disorder is a condition where symptoms of both bipolar and schizophrenia are present. Since some symptoms like hallucinations and delusions are common to both illnesses, other conditions such as catatonia (though this is possible, but rare, in bipolar), difficulty speaking, lack of expression in face, voice and body language must also be present. Also, psychotic and/or other symptoms have to be present in the absence of a manic or depressive episode at least one time.