Hi, Kent. Psychiatry regards bipolar as separate and distinct from schizophrenia. Bipolar is a MOOD disorder and EPISODIC. Schizophrenia is a THOUGHT disorder and tends to be CHRONIC.

Also, people with schizophrenia tend to be far more functionally impaired than those with bipolar.

Having said that, there is clear overlap. Bipolars can have thought impairments and those with schizophrenia can have mood symptoms. Also, psychosis (hallucinations, disordered thinking) features in both bipolar and schizophrenia.

There is an "in between" diagnosis called schizo-affective disorder. Psychiatrists tend to make this diagnosis when it's difficult to make a diagnostic call.

Also, our clinical condition tends not to remain the same over our lifetime. Thus, according to experts, it may be possible to be diagnosed with one illness at one stage in our lives and another at a different stage.