The medicines for ADHD work by increasing the amount of dopamine or norepinephrine that is available. They can also increase the number of their receptors that are available, acting as if to make one number earlier to hit and to make an appropriate connection.
Children who have ADHD have slightly smaller brains than children without the disorder; medications that are used to treat ADHD aren’t causing a difference in brain size and don’t appear to affect the normal brain development.
Dopamine: a chemical found in the brain that acts as a neurotransmitter and is an intermediate compound in the synthesis of noradrenaline.
Norepinephrine: also called noradrenaline, a neurotransmitter, released by adrenergic nerve terminals in the autonomic and possibly the central nervous system, that has such effects as constricting blood vessels, raising blood pressure, and dilating bronchi.
Receptors: an end organ or group of end organs of sensory or afferent neurons, specialized to be sensitive to stimulating agents, as touch or heat.
Noradrenaline: a hormone secreted by the adrenal medulla, increasing blood pressure and heart rate, and by the endings of sympathetic nerves, when it acts as a neurotransmitter both centrally and peripherally.
Neurotransmitter: a chemical by which a nerve cell communicates with another nerve cell or with a muscle.
Synthesis: the forming or building of a more complex substance or compound from elements or simpler compounds.
Adrenergic: releasing epinephrine.
Autonomic: produced by internal forces or causes; spontaneous.