A few weeks ago, in the Ask feature here at BipolarConnect, Nathan wrote:

"Is bipolar the same as schizophrenia? I know a person who has bipolar and another friend of mine says it's just a fancy name people use for schizophrenia. Is this true?"

My quick reply: "Absolutely not true. Bipolar is a MOOD disorder. Schizophrenia is a THOUGHT disorder. There is some overlap, but we can save that discussion for another time."

Now is a good time for that discussion. This week I attended the International Congress on Schizophrenia Research, held in San Diego. As an illustration of the brain power at this conference, at one of the sessions, sitting in the same row as me, was Nobel Laureate Arvid Carlsson.

I was there because schizophrenia research sheds tremendous light on bipolar. Yes, bipolar and schizophrenia are very different illnesses, but there is a lot of overlap between the two, and the same principles of brain science apply to both.

My first insight into this came in 2001 from a review article by Carrie Bearden, now of UCLA, which clearly showed there was a lot more to mood disorders than just mood. A lot of us experience difficulty thinking clearly, even when we're not depressed or manic or on meds. After reading Dr Bearden's article, I started paying a lot closer attention to "the other stuff" that was going on in our brains.

I got a chance to meet Dr Bearden very briefly in 2006 at a bipolar conference in Edinburgh, and had a chance to talk with her more in depth here at the schizophrenia conference. Since she is one of the few researchers studying both illnesses, it is worth quoting from a recent essay of hers:

"Current classification schemas are based on particular clusters of symptoms and clinical course descriptors that do not necessarily describe homogeneous conditions, but rather reflect final common pathways of various pathophysiological processes."

In other words, if we really want to learn what is going wrong inside our brains, we need to be thinking outside the DSM box. Symptoms are merely the end result of what is going on inside the brain, and there are numerous pathways to any particular symptom.

In short, sometimes it pays not to think in terms of make or model, schizophrenia or bipolar. Instead, open up the hood of the brain and take a close look inside. A defective carburetor is a defective carburetor whether it's a Chevy or a Ford.

When it comes to looking under the hood, the schizophrenia researchers have at least a 20-year head start over their counterparts in bipolar. They are much better funded and publish a lot more articles. Let's put it this way: by attending a schizophrenia conference, I stand to gain a lot of insight into bipolar, more so, in fact, than some of the bipolar conferences I have attended.

Psychosis gets all the attention in schizophrenia, but the researchers here were more focused on other cognitive deficits, such as how the brain processes information and performs basic tasks. In other words, schizophrenia is not just about hallucinations and delusions. We have medications that can stop psychosis dead in its tracks, but then we're still left with the problem of non-psychotic patients smoking in day rooms, unable to make a go of it in the real world.