Childhood Trauma and Social Anxiety
Current estimates are that somewhere between 4 and 8 percent of adults suffer from SAD in any year, and that the percentage of people suffering from the disorder at some time in their lives is even higher. Such a rate makes social anxiety, after depression and alcoholism, the third most common psychiatric disorder. Knowing how many people suffer from a disease is, of course, not enough. We'd like to be able to predict which people are going to suffer from a given disease so that we can intervene early to prevent it. To do this, researchers look for risk factors--clues that suggest a disease is likely to occur. In the case of social anxiety (and many other psychiatric illnesses) one of the things they look for is developmental problems in childhood. If a particular kind of childhood problem leads to later social anxiety disorder, it is identified as a risk factor for the disorder, one of the contributing causes of a disease. This is what a team of Canadian researchers did in 2001 when they set about to examine the backgrounds of people with SAD. They depended for their data on a large health survey undertaken by the Ontario Ministry of Health.
The study found that certain childhood events are highly correlated with SAD later in life. Childhood sexual abuse, the lack of a close relationship with an adult, failure in early grades of school, and dropping out of high school were all associated with SAD. So were moving more than three times as a child, involvement with the juvenile justice system, and running away from home. Social class, on the other hand, had no bearing whatsoever on whether a person would suffer from the disorder. Being a firstborn male increased the risk for social anxiety; firstborn females experienced no such increased risk.
But things are never so simple. The authors of the study are careful to point out that these associations are not the same as causes. Itis perfectly plausible, for example, that a child who runs away from home is already suffering from a form of social anxiety, so that it isn't running away that caused social anxiety, but the social anxiety that caused the running away. The same problem might apply to any other of the risk factors identified. So the authors' correlations, accurate though they are, tell little about whether these childhood events actually cause social anxiety.
Childhood trauma seems to play a role in other closely related anxiety diseases as well. Panic disorder and generalized anxiety disorder have both been found to be significantly related to past childhood physical or sexual abuse--in fact, in some studies these disorders appear to be more closely related to such abuse than social anxiety disorder.
Childhood behavior, even when it isn't pathological, might also be a predictor of social anxiety disorder. I see some kids who seem naturally curious; they like to explore new environments, meet new people. Others are more withdrawn. Inhibited behavior--a consistent tendency in children to display fear and withdrawal in any new situation--gives me a hint that social anxiety will develop. A carefully designed study published in 2001 demonstrated that behavioral inhibition was associated with a higher risk for SAD as well as other anxiety disorders. (There was also some good news for shy kids: behavioral inhibition has a lower association with disruptive behavior.)
The next question is why childhood personality or behavior predicts social anxiety in adulthood, and the answer is not at all self-evident. Many feel that childhood experience makes people modify their attitudes about the world and the extent to which they fear it. Some speculate that childhood trauma actually causes biological changes in the brain that lead to social anxiety, and this finds some support in animal studies. By manipulating the environment of young macaque monkeys, and then testing their reactions to anxiety-provoking drugs later in life, researchers were able to show that astressful environment in juveniles was likely to produce anxious adults, and even actual permanent neuronal changes in the animals' brains caused by early experience.
The experiment worked like this. Two groups of five female macaques and their infants were the subjects. In the first group, mothers had easy access to their food rations. In the second group, mothers had to search for their food in a device that hid the rations under a pile of wood chips. This required considerable time--and considerable anxiety--in finding the food. Both groups of infants matured normally, but the second group were raised by anxious parents. Presumably this anxiety would affect their treatment of their infants.
When the infants were six months old, the researchers gave them anti-anxiety drugs. The infants raised by anxious mothers responded more to the drugs as measured by observations of their social behavior than did those raised by non-anxious parents. Apparently, anxious mothers had transmitted their anxiety to their children, even to the extent of causing biological changes that would result in a different response to anti-anxiety medicines.
But of course I treat people, not monkeys, and it has been almost impossible for researchers to connect a specific traumatic event in a person's life to the development of social anxiety disorder. A minority of patients report a specific event that they feel led to the development of their problem, but their reports are not always reliable. Often there is a long delay between the time a patient feels symptoms and the time he seeks help, and in the interval many traumatic events may have happened and been forgotten. It is probably true that traumatic events by themselves are unlikely to be the cause of social anxiety--significant proportions of people without social anxiety have experienced traumatic events, and some studies show as little as 15 percent of those with social anxiety can point to a specific traumatic event as the source of their problem.
Nevertheless, there are some suggestive findings about less dramatic or specific events. Constant rejection or bullying by peers, for example, may sensitize kids who are already at risk for social anxiety. One study found that "behavioral inhibition" in five- to twelve-year-olds (assessed by parents looking back at the past), long-lasting separation from parents, and a parental history of psychopathology were all associated with the incidence of social anxiety. Whether or not any of these things are actual causes of social anxiety, however, is another unanswered question.
Genes and Your Destiny
If it is differences in brain structure that cause a tendency to social anxiety, then it is clear that genetics may also play a part. Everyone notices that "the apple doesn't fall far from the tree," that not only physical appearance but also children's behavior tends to resemble that of their parents. But noticing such similarities is not the same as scientifically proving that they are inherited, and certainly far from proving exactly what the mechanism of inheritance is. The inheritance of physical traits--eye and hair color, height, weight, and so on--is complicated enough. When it comes to the inheritance of behavioral traits, the complexity increases enormously, and the uncertainties begin to multiply.
That shyness is inherited is not a new observation. In 1872, Charles Darwin published The Expression of Emotion in Man and Animals, in which he asserted that shyness--or at least its physiological manifestation in blushing--was an inherited characteristic. He quotes the observations of a physician: "Even peculiarities in blushing seem to be inherited. Sir James Paget, whilst examining the spine of a girl, was struck at her singular manner of blushing; a big splash of red appeared first on one cheek, and then other splashes, variouslyscattered over the face and neck. He subsequently asked the mother whether her daughter always blushed in this peculiar manner; and was answered, 'Yes, she takes after me.' Sir J. Paget then perceived that by asking this question he had caused the mother to blush; and she exhibited the same peculiarity as her daughter." In 1890, William James, in The Principles of Psychology, quoting Darwin approvingly, counted shyness as a basic human instinct.
SAD clearly runs in families. But to say that something "runs in the family" is not the same as saying it is carried in the genes. Sorting out what is genetic and what is environmental is the most difficult part of the problem. One way to do this is with twin studies. Since identical twins have exactly the same genes, differences in twins' behavior can, at least with greater justification than those b...
