Role of Perinatal Adversities on Tic Severity and Symptoms of Attention Deficit/Hyperactivity Disorder in Children and Adolescents With a Tic Disorder:

Objective: To investigate the role of perinatal adversities with regard to tic severity and comorbid attention deficit/hyperactivity disorder (ADHD) symptoms in children with a tic disorder. Methods: In 75 children and adolescents with a tic disorder, we retrospectively assessed presence of pregnancy, delivery, and postnatal complications and of prenatal exposure to smoking and alcohol. Children with and without these perinatal adversities were compared regarding tic and ADHD symptom severity. Furthermore, through linear regressions, we investigated whether perinatal adversities would interact with presence in first-degree relatives of tic or any mental disorders with the tic or ADHD measure as outcome. Results: Presence of delivery complications was related to tic severity and prenatal smoking exposure to severity of comorbid ADHD symptoms. The relationship between smoking exposure in utero and ADHD symptom severity appeared to be more pronounced in children with a positive family history of mental disorders. Conclusion: This study provides evidence of a role for perinatal adversities in the etiology of tic disorders. Children with perinatal adversities may be vulnerable to develop more severe tics or comorbid ADHD symptoms in the presence of a positive family history of mental disorders, suggesting a role for gene-environment interactions.