The State of Monoamine Activity in Children with Tyc Hyperkinesis and the Combined Type of Attention Deficit Hyperactivity Disorder (ADHD)

Abstract

Aim: the primary purpose of this study was to explore the state of monoamine activity in children with tic disorder at a combined type of attention deficit disorder (ADHD). Patients and methods: 404 children aged 6–10 years with a combined type of ADHD were divided into three subgroups according to the monoamine activity: 1 subgroup with a combination of hypofunction of dopaminergic and hyperfunction of the noradrenergic system — 120 patients, 2 subgroup with a combination of hyperfunction of the noradrenergic system with a relative balance of dopamine — 136 patients, 3 subgroups with biochemical parameters of monoamine indicators within the reference values — 148 children. The levels of monoamines, their precursors and metabolic products in daily urine were determined by high performance liquid chromatography with electrochemical detection: dopamine, norepinephrine, adrenaline and serotonin, their metabolites — homovanilic acid, vanillylmandelic acid, 5-hydroxytryptophan and 5-hydroxyindoleacetic acid, and their precursors tryptophan and tyrosine. To assess the severity of the symptoms of ADHD, the SNAP-IV scale was used, and tic severity was determined using the Yale global tick severity scale. Results: сommon to all subgroups under consideration is characteristic that the severity of the tick correlates, fi rst, with increased impulsivity (1 subgroup р = 0.0001, 2 subgroup р = 0.045, 3 subgroup р = 0.015). The degree of manifestation of the main symptoms of ADHD in children has competitive behavior with tics, which is associated with decompensation of the biochemical balance of monoamine systems. In subgroup 1, there is an increase in the consumption of norepinephrine (p = 0.002) with a large formation of metabolites and a further weakening of the activity of the dopamine (p = 0.029) and serotonin (p = 0.038) systems. In subgroup 2, the dopamine system is deficient (p = 0.001) and the inhibitory function of the serotonin system increases (p = 0.003). In subgroup 3, the activity of the noradrenaline system increases with minimal participation of the dopamine system and a weakening of the influence of the serotonin system (p = 0.006). Conclusion: in cases of comorbidity of ADHD and tic disorder in children, observation revealed a change in the state of noradrenergic and dopamine systems and weakening of the inhibitory effect of serotonin, which probably has an effect on the general psychopathological profile.