A new Danish study shows a link between repeated febrile (fever-related) convulsions and the risk of epilepsy and psychiatric disorders such as schizophrenia and depression.

The register-based study involved two million Danish children born between 1977 and 2011. Researchers from the Department of Clinical Medicine at Aarhus University and Aarhus University Hospital in Denmark identified approximately 17,000 children with more than a single febrile convulsion.

This makes the register-based study the most comprehensive thus far to look at the long-term consequences of repeated febrile convulsions. The study is published in the journal JAMA Pediatrics.

“Though previous research has documented an increased occurrence of epilepsy among children with febrile convulsions, this is still one of the first studies to demonstrate such a convincing correlation between febrile convulsions and psychiatric disorders,” says the study’s lead author postdoc Julie Werenberg Dreyer from the National Centre for Register-based Research.

“Not least due to the size of the study, the long period of time that the study covers and the valid Danish data.”

Werenberg Dreyer emphasises that although the study demonstrates a clear link, this is not the same as concluding that febrile convulsions in themselves cause epilepsy or psychiatric disorders.

“A statistical correlation does not necessarily mean that one thing causes the other and that it is the febrile convulsions themselves which have a damaging effect on the brain. But the study’s results are so significant that looking into this more closely is more than relevant when it comes to possibly being able to provide the best possible prevention and treatment,” said Werenberg Dreier.

She says that a future study could look into the significance of genetics for the child’s risk of suffering febrile convulsions and subsequent epilepsy or psychiatric disorders.

“There are still many unknown factors that we don’t know enough about. As we learn more about the importance of genes for health and disease, it may be that it is here we will find an explanation for why some children suffer repeated febrile convulsions and then later in life also develop epilepsy and psychiatric disorders,” she says.

The results show that among children who have three or more attacks of febrile convulsions, the risk of developing epilepsy within 30 years is approximately 15 percent, while the risk of a psychiatric disorder that requires treatment is approximately 30 percent.

In comparison, children with no history of febrile convulsions have a 2 percent risk of developing epilepsy and a 17 percent risk of developing a psychiatric disorder.

“Both epilepsy and psychiatric disorder can be extremely serious and associated with high morbidity and mortality — so in this way the diseases have major consequences for both the individual patient, their family and society,” says Jakob Christensen, a clinical associate professor at Aarhus University and consultant at the Department of Neurology at Aarhus University Hospital. He has conducted intensive research into epilepsy over many years.

The team hopes the results will encourage more research to clarify the link between febrile convulsions and the long-term consequences.

“Our results may be frightening reading for parents who have a child that suffers from repeated attacks of febrile convulsions. But these are families who are already deeply concerned about their children. The new knowledge can help them and healthcare professionals to be extra aware of these children’s health and development,” said Werenberg Dreier.

Source: Aarhus University. Article by Traci Pedersen