Objective: Attention Deficit Hyperactivity Disorder (ADHD) is observed 3-5 times more in boys. The etiology of ADHD is not known precisely. Environmental and genetic factors may both play a role . Child adoption and genetic studies support this view. Being a first child is a risk factor. Stress hormones, nicotine, caffeine, alcohol and their metabolites can pass through the placenta and reach the fetal brain. It is thought that nicotine has a role in the development of ADHD by modulating the dopamine receptors.
Methods: 72 children between the ages of 7 and 13who applied to GMMA (Gulhane Military Medical Academy) child and adolescent psychiatry polyclinic and received a diagnosis of ADHD according to DSM-4 diagnostic criteria, 17 girls (23.6%) and 55 boys (76.4%),were included in the study consecutively. A total of 119 children,60 girls (50.4%) and 59 boys (49.6%) who applied to GMMA pediatric polyclinic and in whom no mental disease was detected according to DSM-IV diagnostic criteria were included into the study, matching the age characteristics with the case group. Exposure to nicotine has been studied in two forms, “active’’ and “passive’’. Information on the exposure to nicotine in the perinatal and postnatal period was analyzed and ranked using a semi-structured form.
Results: The level of exposure to nicotine of the case group was found significantly higher than in the control group (Z=-4.154, p<0.001). The level of exposure to nicotine of the boys within the case group was detected significantly higher than among the boys in the control group (Z=-4.403, p<0.001). No significant difference was detected between the level of exposure to nicotine of the girls in the case group and the control group (Z=-1.109, p=0.267).
Conclusion: Nicotine affects and damages especially the structure of dopaminergic pathways and receptors during the development of the central nervous system. It is remarkable that no significant difference was detected between girls with the diagnosis of ADHD and girls in the healthy control group. This finding supports the assumption that factors other than nicotine contribute to ADHD development in girls exposed to nicotine in the perinatal period. Moreover, it was interpreted as one of the reasons for observing ADHD in boys 3-5 times more frequently compared to girls. This finding is compatible with studies that find the estimated relative risk to be lower in girls. As a result, the obtained data suggested that the exposure to nicotine in the perinatal period is a risk factor for ADHD development, although it is not a determining factor separately. It was detected that this effect is more significant in boys than that in girls.