How the study was done

For the researchers to conduct the study, they brought on board data of more than 73,000 Denmark births. They analyzed this data and found out that the possibility of children whose mothers smoked 10 or more cigarettes during pregnancy stood a higher chance of developing a chronic tic disorder. Their risk was calculated to be 66 percent.

Tics are sudden, repeated, non-rhythmic muscle movements, which are accompanied by sounds or vocalizations. After one has suffered both motor and vocal tic for more than a year, the Tourette syndrome is usually diagnosed. Treatment of tics is only done when they begin to interfere with the child’s self-image or activities. Some of the treatment options available are antipsychotic, clonidine or cognitive behavioural therapy.

The severity of tics is varies widely and they happen in close to 20% of children, most of whom do not undergo diagnosis or any evaluation. The most severe type of tics is Tourette syndrome and happens in happens in 3 – 8 children per 1000. The male to female ratio of occurrence is 3:1.

Typically, tics begin at the ages of 4 years to 6 years but before 18. When the child gets to the age of 10 to 12, they increase to the peak and then start to decline in adolescence. By the time adolescence comes to an end, they disappear completely by progress to adulthood in about 1 percent of the children. The etiology is not defined, but tics seem to be linked to one’s family. There are some families in which it draws a pattern of dormancy.

Scope of the study

Mothers who smoke heavily during pregnancy were shown by the study to have caused twofold to threefold increase in a child’s risk for chronic tics in combination with other neuropsychiatric conditions, like attention-deficit/hyperactivity disorder (ADHD).

Dr. Dorothy Grace, a professor of psychiatry at the Icahn School of Medicine at Mount Sinai in New York City and also senior study author said that it is important we identify causes for chronic tic disorders. The importance of doing so is that once the specific risk factors are known, developing more effective prevention mechanisms would be possible.

Grice continued to explain that the findings of the study are a pointer to the fact nicotine exposure impacts brain development in a fatal manner. But the study failed to prove a cause-and-effect relationship. She said that the next study should aim at knowing how environmental factors affect the risk.

The other effects of maternal smoking are that it causes premature births and birth of underweight babies. This, later on, affects the behavior of the child causing the problems discovered by the study.

The study was published in the September issue of the Journal of the American Academy of Child and Adolescent Psychiatry.