Evaluation of iron and iron-related parameters in children and adolescents with attention deficit hyperactivity disorder

Objective: This study aimed to compare parameters of iron deficiency in patients with attention deficit hyperactivity disorder (ADHD) and healthy controls, investigate the differences among subtypes of ADHD, and assess the relationship between level of ferritin and severity of ADHD symptoms.

Methods: The study included 200 patients with ADHD and 100 healthy controls. The ADHD group consisted of 100 patients with ADHDCombined subtype and 100 patients with ADHD-Predominantly Inattentive subtype. The diagnosis was made using the Schedule for Affective Disorders and Schizophrenia for School-Age Children - Present and Lifetime Version, a semi-structured interview. Levels of intelligence were assessed using a short form of the Wechsler Intelligence Scale for Children. The patients with a history of using atomoxetine or stimulants or any psychotropic agents or iron preparations, those with a comorbid psychiatric disorder or any acute/ chronic systemic disease, and those with a history of infection in the last one month were not included in the study. Clinical evaluations were made using socio-demographic data form, DSM-IV Based Attention Deficit and Disruptive Behavior Disorder Screening and Rating Scale (Parent-Teacher) and Conners’ Rating Scale – Revised: Long Form (Parent-Teacher) (CPRS-R:L, CTRS-R:L).

Results: No meaningful difference was found between patients with ADHD and healthy controls in serum ferritin, serum iron, iron binding capacity, hemoglobin, hematocrit, mean corpuscular volume, red blood cell count, and red cell distribution width parameters; and ADHD subtypes also did not differ from each other in these parameters. A negative correlation was observed between CPRS-R:L Hyperactivity and CTRS-R:L Hyperactivity scores and serum ferritin levels in the ADHD group.

Conclusion: As can be seen, the results of studies on ADHD and serum ferritin levels are still inconsistent. Clarification of findings is considered to be of importance for the etiology and treatment of ADHD. Our study included pure ADHD patients, and ADHD subtypes were very well defined. Examining the literature, it is seen that our study includes the largest number of patients in identification of ADHD subtypes. There is a need for further studies on this subject with a greater number of cases. For further studies, we recommend the analysis of molecules involved in the regulation of iron homeostasis besides peripheral iron parameters.