We Are Our Brains (55 page)

We come into the world with brains that are already unique, shaped by a combination of our genetic background and programming in the womb, and in which our characteristics, talents, and limitations are to a large extent already determined. This applies not just to things like IQ, being an early bird or a night owl, the extent to which we're spiritual, neurotic, psychotic, aggressive, antisocial, or nonconformist, but also to the risk we run of developing brain disorders like schizophrenia, autism, depression, and addiction. By adulthood there is very little about our brains that can be modified, and our characteristics have been established. This structuring of our brains determines their function:
We are our brains.

Our genetic background and a host of factors that shaped our early brain development limit us in many ways. We aren't free to decide to change our gender identity, sexual orientation, level of aggression, character, religion, or mother tongue. That we lack free will isn't a new concept, and I find myself in the best of company here. Spinoza already demonstrated this with a few examples (
Ethics III
, proposition 2): “An infant believes that of its own free will it desires milk, a hot-headed youth believes he freely desires vengeance, a
coward believes he freely desires to run away; a delirious man, a garrulous woman, a child … believe that they speak from the free decision of their mind, when they are in reality unable to restrain their impulse to talk.” Certain qualities simply can't be changed. Charles Darwin came to the same conclusion in his autobiography, theorizing that “education and environment produce only a small effect on the mind of any one, and that most of our qualities are innate.”

However, this view is at odds with the belief in social engineering that held sway in the 1960s and 1970s. Gender-based behavioral differences were blamed on the domineering patriarchal society, and the fact that women were twice as likely to become depressed was thought to be because their lives were harder. The thinking was that since society was causing these problems, something could be done to solve them. But the belief in progress and the importance attached to the social environment had its darker side. When things went wrong, they were attributed to upbringing and especially to the mother's role. A dominant mother would make her son homosexual, a cold mother would have an autistic child, and a mother who sent out mixed messages resulted in a schizophrenic child that needed to be “rescued from the claws of its damaging family.” Transsexuals were considered psychotic, criminality resulted from having the wrong friends, stick-thin models were thought to cause epidemics of anorexia, and abuse or abandonment was said to result in borderline personality disorder. Nowadays very little is left of these credos.

That our characteristics, potential, and limitations are to a great extent determined in the womb doesn't, of course, mean that our brains are “complete” when we're born. A baby's brain continues to develop if provided with affectionate, secure, and stimulating surroundings. It's shaped by a constant process of learning as well as by native language acquisition and the imprint of religious beliefs. And, just as in the womb, the issue isn't about brain versus environment but about the strong interaction between the two. Crucially, however, the earlier that environmental influences come into play, the
stronger and more lasting their effects will be. And the further a child's development progresses, the less scope there is for characteristics still to be programmed in the brain. Our character—that is, our innate qualities—emerges more and more strongly in the course of early development. Of course, what we learn is stored in our memory systems, which provide some ongoing plasticity. Moreover, after early development, society can influence our behavior, but our character can't be changed. And though behavioral changes—often achieved only with considerable difficulty by clinical psychologists and psychiatrists—can help people with personality disorders cope better with the character-related problems that emerged during early development, they don't eliminate such problems. It's not for nothing that the word
character
comes from a Greek word meaning “engraved,” like the symbol stamped on a coin.

Congenital isn't the same as hereditary. The latter term refers to inherited characteristics: From the moment that our father's and mother's genes were shuffled, we were permanently dealt a significant part of our character, IQ, and likelihood of brain disorders. But from the moment of conception, the uterine environment crucially influences brain development. The combination of inherited characteristics and intrauterine effects on brain development gives rise to congenital properties.

It's only very rarely that we can do anything about the genetic burden handed down to a child. In the case of Down syndrome and other chromosomal abnormalities, there's the option of prenatal diagnosis and, if a pathological gene has been found, abortion. Occasionally in vitro fertilization is a possibility, allowing the selection of an embryo that doesn't have the defect in question, which can then be replaced in the uterus. This can, for instance, be done in the case of early-onset or familial Alzheimer's. Heel pricks are used to test
newborn babies for various genetic diseases, treatment of which can prevent damage to the developing brain. One such condition is congenital adrenal hyperplasia (CAH), which prevents the adrenal gland from producing cortisol, leading to overproduction of testosterone. This has the potential not only to disrupt the sexual differentiation of the brain but also to make the child acutely ill. Other disorders scanned for include congenital hyperthyroidism, a condition in which thyroid hormone deficiency impairs brain development, and phenylketonuria, a metabolic disease that can damage the brain but can be treated through a special diet. It isn't yet possible to repair genetic disorders of the brain using molecular technology.

Environmental factors are crucial to brain development, but contrary to what was thought in the 1960s and 1970s, it isn't so much the social environment after birth as the chemical environment before birth that's most influential—and the earlier the stage of development, the greater its impact. Very considerable health gains can be achieved during early development that will have lasting and significant effects on the rest of the child's life. To this end, pregnant women should take medication as sparingly as possible and avoid exposure to other chemical substances that can affect the development of their child's brain. They also need proper nutrition and sufficient iodine to ensure that both their own and their baby's thyroid hormones function properly. We know from experience of the Dutch famine (“Hunger Winter”) of 1944–1945 that intrauterine malnutrition increases the risk of schizophrenia, depression, antisocial personality disorders, addiction, and obesity. Since my own intrauterine residence coincided with that same famine, I was fortunate that my pregnant mother's friends and acquaintances gave her some extra food. Heaven only knows where they got ahold of it. In fact, my mother produced enough milk even to feed another baby—a Jewish infant being secretly sheltered somewhere—whose identity we never discovered. The consignments of milk were delivered by a chain of female couriers. In today's world there are still two hundred million children who aren't as fortunate and who are caught in a vicious
cycle as a result. Malnutrition in the womb disrupts the functioning of their brains, preventing them, when they reach adulthood, from providing the next generation with sufficient food and an optimal start in life. The only way this cycle can be broken is by improving the distribution of the world's food supply. There are also still many regions of the world with an iodine shortage, which leads to fetal thyroid malfunction, resulting in impaired brain development and mental disability. In principle, this problem can easily be solved with iodized salt, if a structural supply could be ensured for these regions.

The lasting effects of chemical substances on early brain development are thought to contribute substantially to psychological and psychiatric problems later in life. These disorders don't emerge until demands are made on the brain systems that were altered during early development. A newborn baby can appear healthy but later prove to have learning disorders because it was exposed to alcohol, cocaine, lead, marijuana, DDT, or antiepileptic drugs before birth. Children run a greater risk of depression, phobias, and other psychiatric problems if their mothers took DES or smoked during pregnancy and a greater risk of transsexuality if their mothers took drugs like phenobarbital or diphantoine. Chemical substances are also thought to contribute to developmental disorders caused by a mix of factors, like schizophrenia, autism, SIDS, and ADHD.

Sometimes achieving health gains seems potentially easy. Twenty-five percent of pregnant women still have the occasional glass of alcohol, and 8 percent smoke. If all pregnant women in the Netherlands were to stop smoking, very premature births would be cut by a third, the number of babies with low birth weight would be greatly reduced, and health costs would be cut by many millions. Add to that the gains resulting from the reduced incidence of
ADHD, which is linked to impulsive and violent behavior and juvenile delinquency, and you wonder why pregnant women still smoke. But theory is one thing and practice another. Achieving behavioral changes is extremely difficult, especially when addictive substances are involved. And nicotine patches aren't without risks to the unborn child either.

A lot of unnecessary medication is taken during pregnancy. Sometimes doctors prescribe drugs under pressure from the patient; sometimes they are passed on by a friend or neighbor. Even over-the-counter drugs like aspirin and acetaminophen can affect the fetus. The thalidomide tragedy raised awareness of the potentially damaging effect of chemical substances on unborn children, but it also left doctors inclined to think that the risk is confined to the first three months of pregnancy. This isn't the case; such substances continue to affect brain development right up to the moment of birth. Take the established practice of administering large quantities of adrenal gland hormones over a prolonged period to promote lung development both in premature babies and babies at risk of being born prematurely. In my inaugural speech thirty years ago I warned against this, having found from animal studies that these substances do help mature the lungs but at the same time impede brain development. Indeed, learning and behavioral disorders, smaller brains, a lower IQ, motor impairments, and an increased risk of ADHD have been found among children who were exposed to large amounts of these hormones. These days they are administered much more sparingly.

Sometimes, though, pregnant woman need treatment for conditions like epilepsy or depression. It's essential that doctors address these problems early on, so that if a patient plans to become pregnant, the safest drug can be prescribed. It would also be beneficial, if at all possible, to consider alternative therapies for pregnant women with depression, like light therapy, transcranial magnetic stimulation, or even placebos—especially since there are justifiable doubts about the effectiveness of antidepressants, while placebos are turning out to be surprisingly effective.

There can be little doubt that our gender identity and sexual orientation are programmed for the rest of our lives while we're still in the womb. Our sex organs differentiate in the first months of pregnancy, while sexual differentiation of the brain takes place in the second half of pregnancy. Since these processes are separate, it's impossible to determine, in those rare cases when children are born with indeterminate gender, whether the brain has developed along male or female lines. In the past, doctors have often been far too quick to operate. They would “make” the baby a girl, to establish clarity for the parents and child. We now know from patient associations that imposed gender identity frequently causes problems in later life. In cases of doubt regarding the sexual differentiation of the brain, it's better to assign a provisional sex until the child's behavior makes its gender identity clear. Some operations can be carried out in such a way as to be reversible.

Since our gender identity is determined so early on in development, it isn't necessary to defer a sex change until an advanced stage of adulthood to be sure that an individual really wants such a change. On the contrary, an early sex change has many advantages. First, it's much better for someone to get used to their new gender before they have finished their education and settled into a career and a relationship. It's of course also easier to turn a man into a convincing woman before he has grown into a hulking six-footer with broad shoulders and a deep voice.