high bipolar rates seen in epilepsy population
denver�not only is depression common among individuals with epilepsy, but bipolar disorder also is present in approximately 10% of these patients, new research shows. Clinicians caring for people with epilepsy should therefore fully assess psychiatric functioning before developing a long-term treatment plan, according to investigators.
A glaxosmithkline-funded mail-in survey of americans indicated that 9.8% of individuals with epilepsy have been diagnosed with bipolar disorder. These results were presented at the 2002 annual meeting of the american academy of neurology.
"we did a retrospective study in 1993 that found something similar," commented ronald lesser, md, professor of neurology and neurosurgery, johns hopkins hospital, baltimore. "there have been other studies that haven�t found that, but there may be an increased prevalence of affective disorders in patients with epilepsy."
primary investigator david blum, md, a physician in clinical development at glaxosmithkline, and two of his colleagues mailed a survey to 127,000 u.S. Households. The survey included demographic questions, medical diagnosis items and the manic-depression questionnaire (mdq). The investigators received completed surveys from a total of 180,997 individuals. This included 2,282 individuals who indicated that they had been diagnosed with either epilepsy or a "seizure disorder." the respondents were very similar to those providing the 2000 u.S. Census data with regard to age, gender, location and household size. These census data were used as a control.
Individuals with epilepsy were similar demographically to those without epilepsy, with whites being by far the most common race among respondents. However, the number of individuals with epilepsy under the age of 18 was significantly larger than that of their counterparts in the general population. Moreover, people with epilepsy, asthma or diabetes were significantly more likely to have annual incomes under $20,000 and significantly less likely to have incomes over $85,000 than the general population. Those with both depression and epilepsy fared the worst at both ends of the income spectrum.
Overall, 29% of respondents with epilepsy reported having a diagnosis of depression, compared to 17% of respondents with diabetes, 16% of those with asthma and 7% of respondents without any of these disorders (p <0.00001 vs. Individuals with epilepsy). Furthermore, 9.8% of individuals with epilepsy had a diagnosis of bipolar disorder, compared to just 2.7% of individuals with asthma, 2.6% of individuals with diabetes and 1.2% of those without these illnesses (p <0.00001 vs. Individuals with epilepsy).
The prevalence of bipolar disorder among the survey respondents was measured with the mdq. The results revealed that people with epilepsy scored significantly higher on all 12 items of the mdq than did survey respondents with asthma or diabetes, and also higher than the general american population. Moreover, while respondents with depression scored higher on the mdq than those with epilepsy, people who had both of these conditions had higher mdq scores than any other group. In total, 8.1% of respondents with epilepsy reached the mdq diagnostic threshold for bipolar disorder.
"it is well known that depressive symptoms are common in people with epilepsy, but there had been no previous surveys of how common bipolar disorder is in this population," said Dr. Blum. "we found that manic/hypomanic symptomatology is more common in people with epilepsy than in any other group studied except those with a formal diagnosis of affective disorder."
dr. Blum and his colleagues are currently conducting a follow-up survey in order to expand on the current findings, including more precisely determining the prevalence of affective disorders and their impact on people with epilepsy.
�rosemary frei, msc