I think the only things that really overlap is that bipolar 1 can also have psychosis and both bipolar 1 and 2 tend to have disorganized thinking especially during a manic or hypo manic episode. It’s also known as flight of ideas.

I’d be interested to hear what he had to say specifically is similar. I’ve got a masters in Counseling Psychology and have worked as a therapist. I would say all mental illness relates in that it can cause distress but specifically linking bipolar disorder and schizophrenia is odd to me, other than what Relhavent said

Did the professor say schizophrenia or schizoaffective disorders? Because there is a difference between the two, with schizoaffective disorders more aligning with bipolar disorder than actual schizophrenia.