When women come to us for consultation, we focus primarily on the risks of exposure to psychotropic medications. It is important, however, to consider the impact of other, potentially harmful, exposures that are common in women who suffer from psychiatric illness. For example, pregnant women with psychiatric illness are more likely to smoke and to use alcohol or recreational drugs. Smoking is relatively common, with about 10% of all women smoking at some point during their pregnancy. The rates are even higher among women with psychiatric illness.
A substantial body of literature supports a link between smoking during pregnancy and externalizing disorders such as attention-deficit/hyperactivity disorder (ADHD), although it has been difficult to separate exposure from genetic vulnerability and other potential confounding variables. Using functional magnetic resonance imaging (fMRI), researchers from the Central Institute of Mental Health in Germany examined the long-term effects of maternal smoking on areas of the brain important to inhibition control.
Functional magnetic resonance imaging was performed for the offspring (n=178) at 25 years of age. Prenatal smoking and lifetime ADHD symptoms were determined using standardized parent interviews at the offspring’s age of 3 months and over a period of 13 years (from 2 to 15 years of age).
The researchers noted that the adults with prenatal exposure to maternal smoking demonstrated hypoactivity in inhibitory regions of the brain, including the anterior cingulate cortex (ACC) and the inferior frontal gyrus (IFG). These changes in brain activity are similar to those observed in patients diagnosed with ADHD.
The authors conclude in stating, “Our results suggest that smoking during pregnancy may have widespread long-term effects on neural activity and development independent of prenatal and postnatal adversity, as well as substance abuse, among the offspring. Therefore, our findings strengthen the importance of smoking cessation programs for pregnant women and women planning to become pregnant, to minimize prenatal exposure to tobacco smoke by the offspring.”
Ruta Nonacs, MD PhD
Holz NE, Boecker R, Baumeister S, Hohm E, et al. Effect of prenatal exposure to tobacco smoke on inhibitory control: neuroimaging results from a 25-year prospective study. JAMA Psychiatry. 2014 Jul 1;71(7):786-96.