Do post-trauma symptoms mediate the relation between neurobiological stress parameters and conduct problems in girls?
OBJECTIVE
Attenuated activity of stress-regulating systems has consistently been reported in boys with conduct problems. Results in studies of girls are inconsistent, which may result from the high prevalence of comorbid post-trauma symptoms. Therefore, the aim of the present study is to investigate post-trauma symptoms as a potential mediator in the relation between stress-regulation systems functioning and conduct problems in female adolescents.


METHODS
The sample consisted of 78 female adolescents (mean age 15.4; SD 1.1) admitted to a closed treatment institution. The diagnosis of disruptive behaviour disorder (DBD) was assessed by a structured interview-the diagnostic interview schedule for children version IV (DISC-IV). To assess post-trauma symptoms and externalizing behaviour problems, self-report questionnaires, youth self report (YSR) and the trauma symptom checklist for Children (TSCC) were used. The cortisol awakenings response (CAR) measured hypothalamic-pituitary-adrenal (HPA) axis activity, whereas autonomous nervous system (ANS) activity was assessed by heart rate (HR), pre-ejection period (PEP) and respiratory sinus arrhythmia (RSA). Independent t-tests were used to compare girls with and without DBD, while path analyses tested for the mediating role of post- trauma symptoms in the relation between stress regulating systems and externalizing behaviour.


RESULTS
Females with DBD (n = 37) reported significantly higher rates of post-trauma symptoms and externalizing behaviour problems than girls without DBD (n = 39). Path analysis found no relation between CAR and externalizing behaviour problems. With regard to ANS activity, positive direct effects on externalizing behaviour problems were present for HR (standardized β = 0.306, p = 0.020) and PEP (standardized β = -0.323, p = 0.031), though not for RSA. Furthermore, no relation-whether direct or indirect-could be determined from post-trauma symptoms.


CONCLUSIONS
Present findings demonstrate that the neurobiological characteristics of female externalizing behaviour differ from males, since girls showed heightened instead of attenuated ANS activity. While the prevalence of post-trauma symptoms was high in girls with DBD, it did not mediate the relation between stress parameters and externalizing behaviour. Clinical implications and future directions are discussed.
Department of Child and Adolescent Psychiatry, VU University Medical Center, p/a De Bascule, P.O. Box 303, 1115 Duivendrecht, The Netherlands.
Kimberly A
KA
Babel
Department of Child and Adolescent Psychiatry, VU University Medical Center, p/a De Bascule, P.O. Box 303, 1115 Duivendrecht, The Netherlands.
Tijs
T
Jambroes
Department of Child and Adolescent Psychiatry, VU University Medical Center, p/a De Bascule, P.O. Box 303, 1115 Duivendrecht, The Netherlands.
Sanne
S
Oostermeijer
Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
Peter M
PM
van de Ven
Department of Child and Adolescent Psychiatry, VU University Medical Center, p/a De Bascule, P.O. Box 303, 1115 Duivendrecht, The Netherlands ; Department of Criminal Law and Criminology, Leiden University, Leiden, The Netherlands.
Arne
A
Popma
Department of Child and Adolescent Psychiatry, VU University Medical Center, p/a De Bascule, P.O. Box 303, 1115 Duivendrecht, The Netherlands ; Department of Child and Adolescent Psychiatry, Curium-Leiden University Medical Center, Leiden, The Netherlands.
Robert R J M
RR
Vermeiren
Department of Child and Adolescent Psychiatry, VU University Medical Center, p/a De Bascule, P.O. Box 303, 1115 Duivendrecht, The Netherlands.
Theo A H
TA
Doreleijers
Department of Child and Adolescent Psychiatry, VU University Medical Center, p/a De Bascule, P.O. Box 303, 1115 Duivendrecht, The Netherlands.
Lucres M C
0000-0001-8475-4050
LM
Jansen
Autonomic nervous system; Conduct problems; Girls; Hypothalamic–pituitary–adrenal-axis; Post-trauma