The role of iron deficiency in children with ADHD – a systematic review

Abstract

Attention deficit hyperactivity disorder (ADHD) is one of the most common developmental neuropsychiatric disorders among children and adolescents. Due to the prevalence of ADHD, there has been a vast interest in knowing its causes. One of the well-known factors involved in the development of ADHD is thought to be the neurotransmitter dopamine, which requires iron in order to be produced in the body. The purpose of this systematic literature review is to investigate the relationship between low iron levels (serum ferritin) and the symptoms of ADHD in children, as well as to study the differences between the different subtypes of ADHD in regards to iron deficiency in children. For this literature review, 12 articles that fit the entry criteria were found. Some of the researches used a setting of study and control groups while others compared the participants within the same experimental group. There was one intervention study as well. Regardless of the diversity of the study design, the researches provided consistent results: the levels of ferritin were significantly lower in the ADHD study groups than in the control groups. Due to the small number of intervention studies, it is not possible to draw very precise conclusions about the quality of the relationship between these two factors; however, there is some evidence of the effect of iron supplements on decreasing the symptoms of ADHD. Differences between the subtypes of ADHD in relation to iron deficiency were not found, but hyperactivity and impulsivity can be seen to be directly related to iron deficiency in children. Based on the results, it seems that discovering and treating iron deficiency as part of the diagnosis of ADHD is important, especially with children presenting symptoms of hyperactivity.