Epilepsy, Schizophrenia Share Close, Unexplained Relationship

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For the first time, researchers have confirmed a bidirectional relationship between epilepsy and schizophrenia. Although experts have some theories to explain this close association, for now it is unexplained and requires further research.

Epilepsy/schizophrenia link needs more study

Epilepsy, a brain disorder in which individuals experience disturbed brain activity (seizures) repeatedly over time, affects about 3 million Americans of all ages and about 50 million people worldwide. In most cases, the cause of the seizures is not identifiable.

Schizophrenia is a disabling, chronic brain disorder that distorts the way a person thinks, acts, perceives reality, and relates to others. About 1.1 percent of adults (age 18 and older) in the United States have schizophrenia. Although its exact cause is not known, schizophrenia does run in families, and research shows people with schizophrenia have an imbalance of certain brain chemicals (e.g., dopamine). Newer research suggests abnormal brain structure may also be involved in some cases.

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The new study, conducted by researchers from Taiwan, reported that patients with epilepsy were nearly 8 times more likely to develop schizophrenia, while individuals with schizophrenia were about 6 times more likely to develop epilepsy. The incidence of schizophrenia was slightly higher in men who had epilepsy than in women with the disease.

Researchers based their findings on data between 1999 and 2008 from the Taiwan National Health Insurance database, from which they found 5,195 patients with schizophrenia and 11,527 individuals with epilepsy diagnosed during that time span. Both groups of patients were compared to age- and sex-matched controls.

In a previous study from Johns Hopkins entitled “Schizophrenia and Epilepsy: Is There a Shared Susceptibility?” the authors suggested that “genes implicated in neurodevelopment may play a common role in both conditions,” and they speculated that “recently identified causative genes for partial complex seizures with auditory features might help explain the pathophysiology of schizophrenia.”

The Taiwan study is important because it demonstrates a strong bidirectional relationship between epilepsy and schizophrenia. According to the lead author I-Ching Chou, MD, associate professor with China Mediccal University in Taichung, Taiwan, “This relationship may be due to common pathogenesis in these diseases such as genetic susceptibility and environmental factors, but further investigation of the pathological mechanisms are needed.”

SOURCES:
Cascella NG et al. Neuroscience Research 2009 Apr; 63(4): 227-35
Chang Y-T et al. Epilepsia 2011 Sep 19 online; doi: 10.1111/j.1528-1167.2011.03268.x
Epilepsy Foundation
National Institute of Mental Health

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Comments

Now every idiot who doesn't know some basic research concepts, i.e. association vs causation, will think the person who has epilepsy will also be developing schizophrenia in the coming months. The cause of schizophrenia is much more dynamic, case specific, and it can't be generalized like the study tries to do. You might find a higher incidence of epilepsy with those who have schizophrenia because of a shared brain injury. However, that won't mean that someone with an existing seizure disorder is more likely to develop schizophrenia. One cannot prove that epilepsy caused schizophrenia through association. In order to prove such a relationship, you would have to show case-specific examples showing that the incidence of seizure increases susceptability while ruling out multiple factors. Let's hope common culture doesn't twist this around and make some more obstacles for those who disclose they ahe epilepsy
That's not what I got out of the article. Clearly, the brain functions between epilepsy and schizophrenia are very similar. Schizophrenic patients often exhibit a trance like state that has been linked to seizure, so the study is important in showing the biodirectional relationship. It would be interesting to know if a family member who had epilepsy, and had a direct descendant that was schizophrenia, had the same brain functioning in common.
after years of seizures my son now 24 his seizures suddenly stopped one day in july 2011 and was left with unconrollable schizophrenia/psychosis