Attention deficit hyperactivity disorder (ADHD) is a most common psychiatric disorder in the childhood. The exact pathomechanisms related to ADHD core symptoms--hyperactivity, impulsivity and inattention--are still unclear. The developmental dysfunction of cortical-striatal-thalamic-cortical network combined with the dysregulation of catecholamine neurotransmitters could be responsible for symptoms of the disorder. Magnetic resonance spectroscopy is a method which allows a partial view on molecular mechanisms of biochemical and metabolic processes in human brain by in vivo measurement. We address the hypothesis of a potential pathomechanisms associated with ADHD symptoms which is based on the studies concerning magnetic resonance spectroscopy method and ADHD.