Iron deficiency and risk of ADHD

Attention deficit hyperactivity disorder (ADHD) is shown as one of the most common disorders in school-aged children. It mostly affects boys, with an estimated global prevalence of 5.9–7.1% of children and adolescents worldwide. Although the underlying pathophysiology of ADHD remains complex and not clearly understood, nutritional factors, like iron deficiency, have been proven to have an important role in this disease.

ADHD symptoms:

• Inattention
• Impulsivity
and/or
• Hyperactive/impulsive behaviours

ADHD side effects:

ADHD has widespread effects on the functioning and development of affected children. In addition, it has considerable impact on others including family members, peers and teachers. ADHD can lead to other disorders and academic difficulties as well as relationship and social functioning problems.

ADHD has long-term adverse effects on social-emotional development, vocational success and academic performance. This affects not only developing countries but also in developed ones. The latter will show as educational difficulty, social exclusion, school dropout and criminality. Recent studies show that this disorder is not limited to childhood but persists throughout the period of adulthood in 30–50% of the sufferers. Unemployment, frequent job switches, divorce and low socio-economic status could be the result of adulthood ADHD.
Beside its impact on quality of life, children with ADHD also suffer from co-occurring medical and psychiatric conditions. For example such as anxiety disorder, depressive disorder, enuresis, restless leg syndrome and serious stomach problems.

Aetiology:

Despite numerous studies investigating the aetiology of the disease, the ADHD’s pathophysiology remains unclear. Prenatal and perinatal risk factors, genetic factors and neurobiological alterations are considered to have a role. ADHD is commonly considered to develop as a result of interactions between genetic and environmental factors.
Genetic factors:
As a predominantly heritable condition, polymorphism in dopamine receptors and dopamine transporters play an important role in the disease’s pathophysiology. Dopamine regulates ADHD’s main clinical features: psychomotor activity and executive functions.
Environmental factors:
Among environmental risk factors, nutritional factors including certain micronutrient deficiencies have been increasingly implicated as possible risk factors for ADHD. Glucose metabolism, fatty acid metabolism, and mineral or vitamin deficiencies, may affect brain function and are associated with the pathogenesis and symptoms of ADHD. In fact Environmental factors are potentially modifiable and may represent preventable targets for these disorders.

Iron deficiency and ADHD:

Iron deficiency has attracted more attention on having a role on the pathogenesis of ADHD. Based on documented evidence in scientific literature, iron deficiency may be associated with many neuropsychiatric manifestations such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder, anxiety disorder and bipolar mood disorders.
Besides, Iron plays an important role in the regulation of dopaminergic activity.

Reduced cerebral iron increases ADHD risk:
• Iron is a cofactor for the enzymes active in the synthesis of some neurotransmitters, like dopamine. Normal iron levels are associated with the normal density of dopamine receptors and dopamine carriers.
• Basal ganglions in the brain need iron for a normal function.

Iron deficiency may lead to ADHD because:

• It will lower the amount of dopamine synthetised, transported and received at its receptors.
• As mentioned above dopamine plays the main role in symptoms of ADHD.

References:

1. Bener A, Kamal M, Bener H, Bhugra D. Higher prevalence of iron deficiency as strong predictor of attention deficit hyperactivity disorder in children. Ann Med Health Sci Res. 2014;4(Suppl 3):S291-S297. doi:10.4103/2141-9248.141974
2. Islam K, Seth S, Saha S, Roy A, Das R, Datta AK. A study on association of iron deficiency with attention deficit hyperactivity disorder in a tertiary care center. Indian J Psychiatry. 2018; 60(1):131-134. doi:10.4103/psychiatry.IndianJPsychiatry_197_17
3. Demirci K, Yildirim Baş F, Arslan B, Salman Z, Akpinar A, Demirdaş A. The Investigation of Symptoms and Diagnoses of Adult-Attention Deficit/ Hyperactivity Disorder in Women with Iron Deficiency Anemia. Noro Psikiyatr Ars. 2017; 54(1):72-77. doi:10.5152/npa.2016.12464
4. Tseng PT, Cheng YS, Yen CF, et al. Peripheral iron levels in children with attention-deficit hyperactivity disorder: a systematic review and meta-analysis. Sci Rep. 2018;8(1):788. Published 2018 Jan 15. doi:10.1038/s41598-017-19096-x
5. Abou-Khadra MK, Amin OR, Shaker OG, Rabah TM. Parent-reported sleep problems, symptom ratings, and serum ferritin levels in children with attention-deficit/hyperactivity disorder: a case control study. BMC Pediatr. 2013; 13:217. Published 2013 Dec 30. doi:10.1186/1471-2431-13-217
6. Lange KW, Hauser J, Lange KM, et al. The Role of Nutritional Supplements in the Treatment of ADHD: What the Evidence Says. Curr Psychiatry Rep. 2017; 19(2):8. doi:10.1007/s11920-017-0762-1
7. Wang Y, Huang L, Zhang L, Qu Y, Mu D. Iron Status in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis. PLoS One. 2017; 12(1):e0169145. Published 2017 Jan 3. doi:10.1371/journal.pone.0169145