The Research On The Function Of Hypothalamus-pituitary-adrenal Axis In Children With Attention Deficit Hyperactivity Disorder

Objective:(1)To investigate the function and pathogensis ofhypothalamic-pituitary-adrenal (HPA) axis in children with attention deficithyperactivity disorder (ADHD).(2) To investigate plasma cortisol levels and behaviorchange before and after taking methylphenidate(MPH) or atomoxetine (ATX) inchildren with ADHD.Methods: Using a prospective, double-blind, randomized case-control trail,children with ADHD were recruited according to the4thediton of Diagnostic andStatistical Manual Ⅳ(DSM-Ⅳ).114ADHD children were classified into threesubtypes:predominantly inattentive type of ADHD(ADHD-I,n=39), predominantlyhyperactive-impulsive type of ADHD(ADHD-HI,n=31),and combined type of ADHD(ADHD-C, n=44),61age-match healthy children were recruited. The cognitivefunction were measured by Raven’s Standard Progressive Matrices(SPM) andbehavior were assessed by Conner Parent Symptom Questionnaire(PSQ)inchildren.The research on function of HPA axis:(1)18children with ADHD and13control children provided saliva,salivary cortisol levels were detected by EnzymeLinked Immunosorbnent Assay(ELISA),the groups were compared with each other.(2)The levels of plasma cortisol(8:00) were determined by Chemoluminescenceimmunoassay in experimental group and control group,the groups were comparedwith each other.(3)24hUFC levels were assayed by Chemoluminescenceimmunoassay in33children with ADHD and20control children,the groups werecompared with each other.(4)Plasma ACTH (8:00)levels of13ADHD children and19normal control children were determined by Electrochemiluminescenceimmunoassay, the groups were compared with each other. The effect of therapy of MPH or ATX:(1)31ADHD children’s symptoms were measured by DSM-IV beforeand after treatment for1month,the results of both groups were compared with eachother.(2) The plasma cortisol levels of45ADHD children were detemined byChemoluminescence immunoassay before and after taking MPH or ATX for1month,the results of both groups were compared with each other.Results:1.General information114ADHD children were classified into three subtypes:39ADHD-I(34.21%),31ADHD-HI(27.19%),44ADHD-C(39.00%),including105males and9females(11:1)and the mean age was8.7±2.3years old(6～16years old).2.The assessment of cognitive functionThere were no significant differences for the scores of Raven Test among thethree subtypes of ADHD（F=1.93,P>0.05）.3.Behavioral assessmentLearning problem、implusive/hyperactive、anxiety,and hyperactivity index inthe three subtypes show no differences(P>0.05),but conduct problem in the ADHD-Cwere higher than those in the ADHD-I,which were lower than those in the ADHD-HI（P<0.05），and Psychosomatic problem in theADHD-I were lower than those in theADHD-C and ADHD-HI based on PSQ(P<0.05).4.The research on function of HPA axis(1)There were no significant differences in salivary cortisol levels betweenADHD group and control group（t=1.45，P>0.05）.(2)The plasma cortisol levels ofADHD subgroups were lower than that of control group after the stress（P<0.05）;Thecortisol levels of ADHD-HI group was significantly lower than that of ADHD-I group（P<0.05）,no significant differences between ADHD-HI group and ADHD-C groupwere revealed（P>0.05）,and so did between ADHD-C group and ADHD-I group（P>0.05）.(3)There were no significant differences for the levels of24hUFCbetween ADHD group and control group（t=1.47,P>0.05）(4)Plasma ACTH levelsbetween ADHD group and control group had no obviously differences（t=0.19， P>0.05）.5.The effect of treatment on plasma cortisol levels and behavior(1)Children with ADHD after treatment had less symptom counts, met theDSM-Ⅳ critria than those before treatment（z=4.46,P<0.01）.(2)The levels of plasmacortisol increased significantly after the therapy(t=5.18,P<0.001).(3)The correlationbetween behavior and plasma cortisol levels before and after treatment in childrenwith ADHD were used to analyse（r=-0.32,P<0.05）.Conclusion：(1)There were no differences on intelligence quotient among thesubgroups of ADHD; conduct problem in ADHD-C subgroup were more serious thanthat of the other two subgroups.(2)Children with ADHD exist hyporeactivity of HPAaxis under stress state.(3)MPH or ATX may improve the symptoms of ADHD, and theelevation is closely related to improvement of behavior.