Background-The aim of the present paper was to investigate the relationship between behavioral symptoms and attentional and executive functions and hematological variables related to iron deficiency and anemia, ferritin, hemoglobin, mean corpuscular volume (MCV), and red cell distribution width (RDW) in children and adolescents with attention deficit-hyperactivity disorder (ADHD).

Objective It has been suggested that both low iron and zinc levels might be associated with Attention Deficit Hyperactivity Disorder (ADHD) symptoms. However, the association of zinc and iron levels with ADHD symptoms has not been investigated at the same time in a single sample. Method 118 subjects with ADHD (age = 7–14 years, mean = 9.8, median = 10) were included in the study. The relationship between age, gender, ferritin, zinc, hemoglobin, mean corpuscular volume and reticulosite distribution width and behavioral symptoms of children and adolescents with ADHD were investigated with multiple linear regression analysis. Results Results showed that subjects with lower zinc level had higher Conners Parent Rating Scale (CPRS) Total, Conduct Problems and Anxiety scores, indicating more severe problems. CPRS Hyperactivity score was associated both with zinc and ferritin levels. Conners Teacher Rating Scale (CTRS) scores were not significantly associated with zinc or ferritin levels. Conclusions Results indicated that both low zinc and ferritin levels were associated with higher hyperactivity symptoms. Zinc level was also associated with anxiety and conduct problems. Since both zinc and iron are associated with dopamine metabolism, it can be speculated that low zinc and iron levels might be associated with more significant impairment in dopaminergic transmission in subjects with ADHD.

Attention defi cit hyperactivity disorder (ADHD) is a neurobehavioral disorder characterized by pervasive inattention and/or hyperactivity-impulsivity. It has been suggested that ADHD symptoms are associated with restless legs syndrome (RLS), which is a neurological condition that is defi ned by an irresistible urge to move the legs. Increasing evidence suggests iron deficiency may underlie common pathophysiological mechanisms in subjects with ADHD and with RLS. To further defi ne the relationship between iron defi ciency and RLS in children and adolescents with ADHD, we evaluated 87 ADHD subjects: 79 boys and 8 girls with age 9.3 ± 2.5 years (6-16 years). Various psychopathologies and the severity of the ADHD symptoms and serum ferritin levels were assessed. Diagnosis of RLS was made according to the International RLS Group criteria. The patients were evaluated for the iron defi ciency (ferritin < 12 ng/ml). RLS was found in 29 (33.3%) of the 87 ADHD subjects. Parentand teacher-rated behavioral and emotional problems and the severity of ADHD symptoms were not signifi cantly different between ADHD subjects with RLS and those without RLS (n = 58). The rate of iron defi ciency was signifi cantly higher in ADHD subjects with RLS (n = 6, 20.7%) when compared with ADHD subjects without RLS (n = 1, 1.7%, p = 0.005). Our results showed that depleted iron stores might increase the risk of having RLS in ADHD subjects. Iron defi ciency, which is associated with both ADHD and RLS, seems to be an important modifying factor in the relationship between these two conditions. restless legs syndrome; attention defi cit hyperactivity disorder; iron defi ciency; ferritin; dopamine

Our aim was to investigate the relation between behavioral symptoms and hematological variables which are related with iron deficiency and anemia, ferritin, hemoglobin, mean corpuscular volume (MCV), and reticulosite distribution width (RDW) in children and adolescents with pure Attention Deficit Hyperactivity Disorder (ADHD) or ADHD comorbid with other psychiatric disorders. The sample consisted of 151 subjects with ADHD, 45 of these subjects had other comorbid conditions. Conners Parent (CPRS) and Teacher Rating Scales (CTRS) were obtained. Comorbid ADHD subjects had lower mean hemoglogin and MCV. In the ADHD group in general, CPRS and CTRS Total scores were significantly negatively correlated with ferritin level. When only pure ADHD subjects were taken into account, the correlations did not reach statistical signifance. Overall, these results suggested that lower ferritin level was associated with higher behavioral problems reported by both parents and teachers. Presence of comorbid conditions might increase the effect of lower iron stores on behavioral measures.

Background Iron is a co-factor of tyrosine hydroxylase which is a critical enzyme in dopamine synthesis. Dopamine has been implicated in the pathophysiology of ADHD. Our objective was to investigate the association of ferritin level with parent and teacher ratings and cognitive measures after controlling for age, gender, ADHD subtype, comorbid conditions, hemoglobin, mean corpuscular volume and reticulosite distribution width in a large sample. Methods The study included 713 children and adolescents with ADHD (613 males; age 7–15). Conners Parent Rating Scale (CPRS) and Conners Teacher Rating Scale (CTRS) were obtained. In a subgroup of patients we conducted Digit Span, Digit Symbol, Trail Making Tests as measures of attention and executive functioning. Results Multiple regression analysis indicated that CPRS Hyperactivity score was significantly associated with ferritin level (B=−.12; t=−3.1; p:.002). Other CPRS and CTRS scores as well as cognitive measures were not associated with ferritin level. Conclusions Although it is not possible to make an inference on causality in cross-sectional studies, the results of this largest scale cross-sectional field study to date suggest that lower ferritin level might be associated with parent-reported hyperactivity after controlling for important confounding factors.