The theory that early life experiences are "imprinted" in the brain has been used to explain a number of phenomena. It is the reason an infant goose, goat or turtle has nearly unerring knowledge of who its mother is and how to behave.
Now, the notion of imprinting is being applied to humans to explain not how babies live their lives but how, years later, they choose to end them.
According to Dr. Bertil Jacobson of the Karolinska Institute in Stockholm, birth trauma may be imprinted on the infant brain and replayed as a suicide or fatal drug or alcohol abuse later in life. In fact, Jacobson will report next month in San Francisco at the International Congress on Pre- and Perinatal Psychology, the specific type of birth trauma -- asphyxia, forceps delivery, or obstetrical anesthesia -- seems to predict the particular way an adult later takes his or her life.
Jacobson and his colleagues examined the birth records of 412 young Swedes who had killed themselves or died of drug or alcohol abuse between 1978 and 1984. Most of the victims were male and all were younger than 44. They compared those records with those of 2,910 controls who had been born at the same hospitals in the same years.
The scientists found that suicide victims who died by asphyxia -- hanging, strangulation, drowning or gas intoxication -- were more than four times as likely as controls, and significantly more likely than victims who poisoned themselves, to have suffered birth asphyxia. Asphyxia is lack of oxygen to the brain during delivery, usually caused by a crimp in the umbilical cord.
Similarly, those who chose death by mechanical injury -- hanging, strangulation, jumping from heights or firearms -- were
more than twice as likely as controls to have undergone mechanical birth trauma, such as forceps delivery, breech birth or entanglement in the umbilical cord. They were also significantly more likely than self-poisoners to have suffered this kind of trauma at birth. And they were the only category with a higher-than-expected incidence of twinning, which Jacobson believes might add to the physical trauma of birth.
"Self-destructive behavior has many roots," Jacobson notes. "They could involve either psychological trauma or neurological injuries . . ."
Jacobson leans toward imprinting as an explanation. "The mechanism must be due to an utterly enhanced receptivity during the early period in life," Jacobson says, leading to "an unconscious need to repeat a traumatic experience at birth as an adult."
If his hypothesis is correct, he adds, the increased use of obstetrical intervention may help explain the rising rates of suicide and drug abuse among young people in several countries, including the United States, Canada and Australia. In any event, Jacboson recommends obstetric practices "be carefully evaluated and possibly modified so as to prevent eventual self-destructive behavior."