Researchers have found provocative evidence that the brain dysfunctionthat underlies epilepsy may also determine whether people are at riskfor suicide. The study, published online October 10, 2005 in the Annalsof Neurology (www.interscience.wiley.com/journal/ana), also suggests that depression and suicide may have different brain mechanisms.
"For reasons that are not understood, depression both increases therisk for developing epilepsy and is also common among people withepilepsy who experience many seizures," said lead author Dale C.Hesdorffer, Ph.D., of the Gertrude Sergievsky Center at ColumbiaUniversity.
It has commonly been assumed that the difficulties associatedwith living with epilepsy could provoke depression, and in some cases,an increased risk of suicide, the authors write. But is harder toexplain the opposite findings, that people who develop depression havea higher risk of later experiencing a first seizure.
While neuroscientists have postulated overlapping brain systemsfor depression and epilepsy, this evidence is still preliminary. In thepresent study, the researchers attempted to define more clearly therelationship between depression, suicide, and epilepsy.
"One question we had was whether some symptoms of depressionwere more important than others for increasing the risk for developingepilepsy," said Hesdorffer. "Suicidal thoughts and suicide attempt werepossibilities, because people with epilepsy seem to be more likely tocommit suicide than the general population. But we looked at allsymptoms of depression."
Hesdorffer and colleagues compared data for both epilepsy and depression in 324 people with epilepsy and 647 control subjects.
A history of depression increased the risk of epilepsy, but thestartling finding was that people with epilepsy were 4 times morelikely to have attempted suicide before ever having a seizure, evenafter other factors were taken into account like drinking alcohol,having depression, age, and gender.
The individual presence of other symptoms of depression,whether common (e.g., depressed mood) or more rare (e.g., weightchange) did not predict a greater likelihood of later seizures.
While this finding clearly suggests common underlying brainmechanisms for suicidal behavior and epilepsy, the results also suggestthat depression and suicidal behavior may be related to differentmechanisms.
"Increasingly, clinicians treating people with epilepsy askabout current depression, but they may not ask about past suicideattempt or suicidal thoughts," said Hesdorffer. "Our results may alertclinicians to the need to ask this question and offer any neededcounseling to prevent the occurrence of later completed suicide."
"We plan to follow up with studies designed to see whether theco-occurrence of these disorders is explained by shared geneticsusceptibility, and with studies that examine possible commonunderlying neurotransmitter abnormalities," said Hesdorffer.
Article: "Depression and Suicide Attempt as Risk Factors forIncident Unprovoked Seizures," Dale C. Hesdorffer, W. Allen Hauser,Elias Olafsson, Petur Ludvigsson, and Olafur Kjartansson, Annals ofNeurology; Published Online: October 10, 2005 (DOI: 10.1002/ana.20685).
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