Epilepsy patients may be prone to bipolar disorder

Bipolar symptoms appear to be more prevalent among people with epilepsy than among those with other chronic medical conditions, new research indicates.

People with Bipolar disorder experience extreme swings in mood, from Depression to mania. Dr. Alan B. Ettinger, of Long Island Jewish Medical Center, New York, and colleagues used the Mood Disorder Questionnaire to assess the prevalence of bipolar symptoms in a community-based sample of 85,358 US adults.

The team compared 1236 respondents with epilepsy to 8994 people with migraine, 7951 asthma patients, 7342 subjects with diabetes, or a healthy comparison group of 57,172 individuals. The results are published in the medical journal Neurology.

Bipolar symptoms were present in 12 percent of the epilepsy patients - about two times more common than in those with migraine, asthma, or diabetes, and over six times more common than in the healthy group.

"Our findings suggest that bipolar symptoms and perhaps formal Bipolar disorder may be significantly underrecognized in patients with epilepsy and patients with other chronic disorders," Ettinger said in an interview with Reuters Health.

The author noted that one reason bipolar symptoms may be missed in patients with epilepsy is because some of the commonly used anti-epileptic agents may be treating the bipolar symptoms as well.

Epilepsy is a disorder involving repeated seizures of any type. Seizures ("fits") are episodes of disturbed brain function that cause changes in attention and/or behavior. They are caused by abnormal electrical excitation in the brain.

Sometimes, seizures are related to a temporary condition, such as exposure to drugs, withdrawal from certain drugs, or abnormal levels of sodium or glucose in the blood. In such cases, repeated seizures may not recur once the underlying problem is corrected.

In other cases, injury to the brain (e.g., stroke or head injury) causes brain tissue to be abnormally excitable. In some people, an inherited abnormality affects nerve cells in the brain, which leads to seizures. In some cases, no cause can be identified.

"The elevated rate of bipolar symptoms in epilepsy may (explain) the commonly described vulnerability to mood instability in individuals with epilepsy," Ettinger said.

SOURCE: Neurology, August 2005.