Relation of maternal stress during pregnancy to symptom severity and response to treatment in children with ADHD.

Objective: There is considerable evidence that maternal stress is associated with behavioural disturbances in offspring. The objective of this study was to examine whether there is an association between the severity of maternal stress during pregnancy and the severity of symptoms of attention-deficit hyperactivity disorder (ADHD). A second objective was to examine whether there is an association between maternal stress and children's response to methylphenidate (MPH).

Methods: Using the Kinney Medical and Gynecological Questionnaire, we assessed 203 children with ADHD, aged between 6 and 12 years, regarding maternal stress during pregnancy. We assessed symptom severity with the Child Behavior Checklist (CBCL) and Conners' Global Index for Parents (CGI-P) and Teachers (CGI-T). Subjects were recruited from the ADHD clinic and the day-treatment program of the Child Psychiatry Department of the Douglas Hospital, Montréal, Quebec. The quality of their therapeutic response was assessed in a double-blind, placebo-controlled randomized 2-week crossover trial of MPH.

Results: The most severe symptoms as assessed by the CBCL were found in the moderate stressor group, (p < 0.002), whereas, according to the CGI-P (emotional liability), the most severe symptoms were found in the severe stressor group (p < 0.029). There was no statistically significant difference between degree of response to MPH and level of maternal stress.

Conclusion: Children with ADHD whose mothers were exposed to moderate and severe stress during pregnancy tend to develop more severe symptoms than children with ADHD whose mothers were not exposed to prenatal stress. It is therefore important to minimize stress in pregnant women.