Intellectual and behavioral characteristics and their relations with serum 5 hydroxytryptamine level in children with attention deficit hyperactivity disorder complicated by oppositional defiant disorder

Xueping GAO

ABSTRACT

BACKGROUND:

Oppositional defiant disorder(ODD) often occurs as a comorbid condition of attention deficit hyperactivity disorder(ADHD),characterized by defiant behaviors.ADHD children with ODD have more extensive impairments than those with ADHD alone. Some studies suggest that decreased serum 5 hydroxytryptamine(5 HT) level is related to aggressive behavior in ADHD, but no relevant report is available in China.

OBJECTIVE:

To investigate the clinical features of ADHD with ODD,and their relations with serum 5 HT.

DESIGN:

A randomized case controlled study taking the ADHD children with or without ODD as the subjects for study.

SETTING:

Mental Health Institute of the Second Xiangya Hospital.

PARTICIPANTS:

Sixty one ADHD children(53 boys and 8 girls) aged 7 to 14 years visiting the Children's Clinic of Mental Health Institute of Central South University from June 2002 to May 2003 were recruited and divided into two groups based on the symptomatic criteria of ODD recommended by the Diagnostic and Statistical Manual of Mental Disorder(DSM Ⅳ )ADHD group(n=33,without ODD) and ADHD+ ODD group(n=28).

INTERVENTIONS:

The parents of the enrolled children(n=61) were asked to complete the Achenbach child behavior checklist (CBCL),and the teachers(n=31) completed the teacher's report form (TRF).Two milliliters of fasting venous blood was drawn from these children and the serum separated by centrifugation for quantification of 5 HT using external standard method,and whole blood 5 HT was analyzed by LD 10AD high performance liquid chromatography(HPLC). MAIN OUTCOME

MEASURES:

Scores of CBCL,TRF and Chinese Wechsler Intelligence Scale for Children(C WISC) and serum 5 HT levels.

RESULTS:

In the ADHD+ ODD group,the scores of CBCL and TRF for externalizing, aggressive behaviors and total scores for behavioral problems rated by the parents and teachers were significantly higher than those of the ADHD group(t=2.28 to 3.76,P< 0.05 to 0.01);the former group also had significantly higher scores of CBCL for anxiety/depression and internalizing(t=2.27 to 2.35,P< 0.05), but had significantly lower serum 5 HT level[(327.01± 164.84) μ g/L vs (451.11± 250.89) μ g/L](t=2.32,P< 0.05).

CONCLUSION:

Children with ADHD and comorbid ODD receive poorer ratings on all variables including externalizing and internalizing problems,adjustment variables and attention impairment. Increased aggressive behavior and lowered 5 HT level may be the biological markers of impulsive behavior in ADHD children with ODD.