Iron Status in Children With Attention Deficit Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent neurodevelopmental disorders, affecting ~5-8% of children worldwide. For about 60% children with ADHD, the symptoms persist into adulthood. Individuals with ADHD have poorer educational and social outcomes, increased injury incidences during daily activities and an elevated risk of developing more severe mental disorders.

Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder defined by persistent, impairing and developmentally inappropriate inattentive/disorganized and/or hyperactive/impulsive behaviors that lie at the far end of a normally distributed continuum.

Dopamine is one of the key neurotransmitters in the brain. Besides its regulatory role in motor and limbic functions, dopamine also regulates cognition, attention, and reward, each of which is impaired in ADHD. The nigrostriatal dopamine pathway is involved in motor control, while the mesolimbic dopamine pathway is involved in motivation and reinforcement learning. The mesocortical dopamine pathway originating in the ventral tegmental area (VTA) and projecting to the prefrontal cortex (PFC) plays a role in cognitive functioning.

Brain iron homeostasis may be important in the pathophysiology of ADHD because iron is a cofactor of the rate-limiting enzyme tyrosine hydroxylase, which is required for dopamine synthesis in the metabolism of dopamine and the hypodopaminergic state of the brain in ADHD results in the symptoms of the disorder. Moreover, iron is colocalized with dopamine in the brain of children with ADHD.

In children, iron deficiency can therefore lead to delayed cognitive, motor, attention and memory deficits, visual and auditory deficits, decreased school performance, and/or behavioral disorders, some with persistent long-term effects.