An 2006 issue of the Journal of the American Medical Association (JAMA) suggests that abnormalities in the lower brainstem affecting serotonin production may be a major predisposing factor in the occurrence of Sudden Infant Death Syndrome (SIDS) in infants. The neurotransmitter serotonin is best known for its mood-regulating characteristics (many current antidepressant drugs affect the regulation of serotonin in the brain), but it also plays a vital role in regulating blood pressure and breathing. The research took place at the Children’s Hospital in Boston, Harvard Medical School, and at a number of other institutions. SIDS is the sudden and unexpected death of an infant under the age of one which can’t be explained after an autopsy, a review of the infant and family’s medical history, or an investigation of the scene and circumstances of the death. Typically, the infant is found dead after being put into bed to sleep.
The lower brainstem controls basic vital processes such as breathing, blood pressure, heart rate, body temperature, and arousal. In comparing the brains of infants who had died from SIDS with those who had died from other conditions, researchers discovered that the brainstems of children with SIDS has more neurons that produced serotonin, yet the neurons themselves seemed to have fewer receptors for serotonin (places where the neurotransmitter is received by the next neuron in the transmission of nerve signals from neuron to neuron), than infants in the control group. Researchers hypothesize that SIDS infants have difficulty producing serotonin in the lower brainstem, thus creating communication problems between brain cells responsible for breathing and other vital functions. They see the larger than normal number of serotonin-producing neurons as a means of compensating for this per-neuron serotonin insufficiency. These discoveries promise that SIDS may no longer be the great mystery it has been to infant researchers, but may be studied scientifically, and eventually result in the development of a drug or other intervention to optimize a newborn’s serotonin levels in the lower brainstem, and thus prevent SIDS. SIDS kills an estimated 2500 infants in the United States every year. For more information on SIDS, including recommendations for preventing SIDS (such as positioning the infant to sleep on his/her back) click here. To read the abstract of the original research paper, click here.