Are bipolar disorder and schizophrenia very similar?
Posted Feb 09 2010 8:32pm
This is a two part question that was asked to a doctor on CNN and I found his answers to be quite interesting so I decided to post both parts here.
Are bipolar disorder and schizophrenia very similar?
The issues you raiseTonyare so interesting that I am going to devote this week and next week's answer to addressing them. And apologies in advance for using a little more academic language than I normally do.
Modern psychiatry is built around diagnosing psychiatric disorders based on three primary factors: clustering of symptomscourse of symptoms over time and degree of life impairment that results from these symptoms.
Think for a moment about how different this approach is from the way most medical disorders are diagnosed and treated these days. Let's say you develop crushing chest pain and shortness of breath. You go to the ER. Do they make a diagnosis of heart attack (myocardial infarctionor MI) based on your symptoms?
Nothey order a blood test that will show whether heart muscle is dying. And they get an electrocardiogramto measure electrical activity in the heartwhich changes in very specific ways in the context of an MI. If these tests are positiveyou are admitted and rushed off for other tests and interventions. If the tests are negativeyou are told that you are probably having an anxiety problem and referred to a psychiatrist.
We have no blood tests in psychiatrynothing like an electrocardiogram. All we have are symptoms we can watch over time. In this waywe are in a situation not so different from doctors in other fields of medicine 100 years agobefore organs such as the heart and lungs began yielding their secrets to technology.
I say all this as a prelude to addressing your first question about how similar schizophrenia and bipolar disorder areand if they are similarhow they can be told apart. It turns out that this question is where modern psychiatry began.
In the 19th centurypsychosis was considered to be a single condition characterized by various symptoms consistent with a person being disconnected from reality. It took a gentleman named Emil Kraepelin -- who is often considered the father of biological psychiatry -- to notice around the turn of the 20th century that although psychotic states looked similar to one anotherpeople with psychosis seemed to follow one of two long-term disease courses.
One group of people developed psychosis early in life and had a progressive decline in their ability to think and function that was unremitting and terrible. Reflecting the degeneration that accompanied this stateKraepelin called this condition "dementia praecox." Today we call this schizophrenia.
Another group of people who developed psychotic symptoms tended to do so a little later in life. Rather than showing a constant declinethese people circulated in and out of madnessand they were always either depressed or elated when they lost touch with reality. To this conditionKraeplin give the name manic depression -- a term that although still in usehas been supplanted by the category of "bipolar disorder" in official psychiatric nomenclature.
So notice that the essence of the distinction between schizophrenia and bipolar disorder has nothing to do with the type of psychotic symptoms that a patient demonstratesbut rather with the course of the symptoms over time.
This insight got lost for half a century when psychoanalysis reigned supremebut made a strong comeback in the 1960s and 1970s with the advent of new scientific techniques for studying the brainand more importantlythe availability for the first time of medications that had profound effects on psychosis and mood disorders.
Especially relevant to the distinction between schizophrenia and manic depression was the discovery that lithium was often a miracle drug for people with bipolar disorder but was generally of little use in schizophrenics. This pharmacological truth seemed to powerfully validate Kraepelin's ideas. From the marriage of Kraepelinnew scientific techniques and new medications was born the modern psychiatric diagnostic guidelines that can be found in the DSM-IV.
So that's a little history. Next week I'll turn to the task of answering your questions directly. But by way of preview I can tell you that the certainties that launched modern diagnostic psychiatry have mostly vanishedand continue to fade with each new scientific discovery. So the short answer to your questions is that schizophrenia and bipolar disorder are increasingly looking more similar than separate.
This week we pick up where we left off last week. If you didn't see last week's entry regarding this questionclick here.
When I was a psychiatry resident at UCLA I had an ongoing friendly disagreement with a friend of mine named Matthew Statewho was one of the best residents I ever knew and who has gone on to become a famous psychiatric genetics researcher. Matt maintained steadfastly in those years that because psychiatric disorders actually existed as distinct entitiesevery patient could be described fully by one or more diagnoses. If you couldn't do this you hadn't tried hard enough.
In contrastI maintained thenand still maintainthat psychiatric diagnoses are like Platonic idealsthey are "perfect types" that patients more or less approximate. Because of this some patients have histories that walked right out of the DSM-IV diagnostic manualbut others have stories that fall between the diagnostic cracks and thatthereforewill never fit a diagnosis very well no matter how hard you try.
You can see why I'm telling this story. While modern psychiatry was built to no small degree upon the belief that schizophrenia and bipolar disorder were separate psychotic illnessesI think data increasingly suggest they are more similar than different. You can see this any way you look at it.
More and more studies suggest that they share genetic risk factors. Thatin factthere may be some genes that predispose one to psychosis and other genes that predispose one to mood disorders. If you just get the psychotic genes you look schizophrenic. To the degree you get both types of risk genes you look more bipolar. Although as I mentioned last weeklithium works for bipolar disorder but not for schizophreniain the last decade a small army of medications has been introduced onto the market that work well for both conditionsstrongly suggesting a shared neurobiology.
Finallylong term follow-up studies have shown that schizophrenia doesn't always lead to an unremitting downward spiralandunfortunatelybipolar disorder is not a condition characterized by no long-term damage. In factit is increasingly clear that the deterioration in functioning over time that was once thought to be a hallmark for schizophrenia is also very common in people with bipolar disorder.
So these comments answer your first and third questionleaving the question of how to tell a psychotic mania apart from a schizophrenic psychotic episode. Every psychiatrist in the world believes he or she can do thisbut the best data on the issue suggest this isn't true. In factany symptom present during a psychotic episode can occur in people whoover timelook more schizophrenic or who look more bipolar. Having said thishoweverbecause I am a psychiatrist Ilike everyone elsethink I can make an educated guess about whether someone is manic.
Here are a few clinical "pearls" for identifying a manic psychosis. Firstmanias tend to come on more quickly than schizophrenic episodes. They are often preceded and accompanied by remarkable reductions in sleep. Classic manic episodes are characterized by profound mood changes. These are easiest to recognize when the mood is euphoricbut rage is just as commonand more dangerous. If you see a psychotic patient who is moving and speaking a million miles an hourthat doesn't prove he is manicbut it is a pretty strong clue. Finallyalthough data show you can't separate out manic from schizophrenic episodes by the quality of the psychotic delusionsI have always been impressed by the fact that at the core of manic delusions is a sense that everything in the universe is connected in strange and meaningful ways. Again this isn't specific for maniabut if this type of thinking is present along with other symptoms I've describedit is a tip that someone is having a manic episode.
So let me end on one final note of confusion/uncertainty. Long-term studies of patients who are schizophrenic suggest that a high percentage of them will have at least one manic episode in their lives! So what is the take-home message? Both schizophrenia and bipolar disorder are serious and often devastating conditions that have the best outcomes when treated early and aggressively. You don't want to leave someone in any type of psychotic state for one moment longer than you have to.