August 23rd, 2011
01:29 PM ET
Every weekday, a CNNHealth expert doctor answers a viewer question. On Tuesdays, it's Dr. Charles Raison, an associate professor of psychiatry and behavioral sciences at Emory University, and an expert in the mind-body connection for health.
Question asked by Benjamin from St. Catharines, Ontario
I was wondering if my brother, who we have been told is bipolar, could develop schizophrenia? My uncle, my mom's brother, was schizophrenic and unfortunately fell victim to the mental illness. We are aware that there have been some mental health issues with males on my mother's side of the family, so could it be possible that he could be schizophrenic as well as bipolar?
Your question points to a major problem confronting the field of psychiatry, which is the imprecision of our diagnostic categories. The problem has a simple cause but no simple answer.
The cause comes from the fact that all our disease states are based on symptoms and how they are clustered together, rather than on any real biological mechanism.
In this way, our diagnoses are similar to the way most medical illnesses were defined before the 20th century. For example, in the old days people with fluid in the lungs and chest pain were said to have pleurisy - it was defined by its symptoms.
Nowadays we recognize literally hundreds of different reasons for pleurisy symptoms, many of them with specific treatments that have no effect on other causes for pleurisy.
Diseases such as schizophrenia and bipolar disorder are like pleurisy and not like adenocarcinoma of the lung or pneumococcal pneumonia or an aortic dissection, all of which cause pleurisy, but all of which are disease conditions based on an understanding of physical mechanisms rather than symptoms.
Both schizophrenia and bipolar disorder are better thought of as syndromes rather than specific diseases. As such, someone has schizophrenia if he or she meets symptom criteria for schizophrenia spelled out in the diagnostic manual. The same thing holds for bipolar disorder.
It sounds simple enough, but things immediately get complicated. First, schizophrenia and bipolar disorder share important symptoms; for example, psychotic thought and behavior can be present in both conditions, making the syndromes hard to differentiate.
If a person is heavy on psychosis and relatively light on either depression or mania, he or she looks schizophrenic and is called such. If a person is heavier on depressions and manias and only has psychotic episodes when in a mood state, he or she looks more like someone with bipolar disorder and is called such.
To add to our diagnostic troubles, over time many people's symptom patterns swing from mostly psychotic to mostly mood-related and back again, making them sometimes seem schizophrenic and sometimes bipolar. And other people spend most of their lives in an intermediate state, with lots of psychosis and lots of depression or mania, but not enough to be fully bipolar. These people are called schizoaffective.
By definition, a person can't have bipolar disorder and schizophrenia at the same time. But a person can sure struggle for years with psychosis, odd behavior and mood swings and be hard to classify clearly into one diagnosis or the other, which sounds to be the case with your brother.
In the midst of these complications, there is some good news. More important than his exact diagnosis (which is after all only a description of his symptoms and how they cluster over time) is the fact that both schizophrenia and bipolar disorder respond to similar medications.
The important thing is not his diagnosis, but his need to get into - or remain in - consistent treatment, which offers the best hope of providing a hopeful long-term outcome.
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