Fainting may be genetic. That’s the conclusion of a new study that has found a strong tendency for fainting to run in families.
The study, published in Neurology, the medical journal of the American Academy of Neurology, is based 51 sets of twins – at least one of which had a history of fainting. Researchers from the University of Melbourne in Victoria, Australia, surveyed the twins – between the ages of nine and 69 years – about their own fainting spells and whether there was any family history of fainting.
Of the 51 sets of twins, researchers found 57 percent reported having typical fainting triggers. The results also showed identical twins (from the same fertilized egg) were nearly twice as likely to both faint compared to fraternal twins (those from two different fertilized eggs).
"The question of whether fainting is caused by genetic factors, environmental factors or a mixture of both has been the subject of debate," said Dr. Samuel F. Berkovic, a member of the American Academy of Neurology who helped conduct the study. "Our results suggest that while fainting appears to have a strong genetic component, there may be multiple genes and multiple environmental factors that influence the phenomenon."
Fainting, also called vasovagal syncope, is a brief loss of consciousness when the body reacts to certain triggers, such as emotional distress or the sight of blood.