Lower serum ferritin levels and higher inattentiveness in attention deficit hyperactivity disorder in a case–control study

Abstract

Introduction: Attention deficit hyperactivity disorder (ADHD) has hyperactivity, impulsivity, and inattentiveness. Brain iron stores influence dopamine synthesis and behavior. Serum ferritin is a marker for iron stores. Few studies are there on serum ferritin levels in ADHD, and the results showed either way as low or equal to controls. Contradictory results were observed in two published Indian studies, hence the need for the study. Aims and Objectives: The objectives of this study were to compare serum ferritin and hematological indexes between children with ADHD and normal controls and also to compare ADHD subscales in two of ADHD groups divided on a cutoff serum value of below 15 ng/ml (World Health Organization criteria). Materials and Methods: Children with ADHD without comorbidities were compared with controls at a child and adolescent psychiatry unit, Hyderabad, India, after ethics committee approval. The assessments included Conners' Parent Rating Scale (CPRS)-Revised (S), serum ferritin, and hematological indexes. Results: Two-three children with ADHD and 38 normal children as controls participated. The mean (standard deviation [SD]) of serum ferritin levels in the ADHD group 28.26 (16.46) and controls 23.06 (18.88) was not statistically significant. Significantly higher mean values (14.60) on cognitive/inattention subscale was noticed In below (15 ng/ml) serum ferritin level group compared to the mean (11.50) in above (15 ng/ml) serum ferritin group. Negative nonsignificant correlation (r = −0.366) between cognitive-inattention subscale of ADHD and serum ferritin levels was noticed. Conclusions: Iron-deficiency state showed higher inattentiveness on CPRS subscale than noniron-deficiency state. There is a weak negative correlation between serum ferritin and inattentiveness.