The low arousal theory is a psychological theory explaining that people with attention deficit hyperactivity disorder (ADHD) and antisocial personality disorder seek self-stimulation by excessive activity in order to transcend their state of abnormally low arousal. This low arousal results in the inability or difficulty to sustain attention on any task of waning stimulation or novelty, as well as explaining compulsive hyperactive behavior.
A person with low arousal reacts less to stimuli than one without. This individual, according to Hare (1970) is "in a chronic state of 'stimulus-hunger'". To further explain, Mawson and Mawson (1977) claim that the individual needs more "sensory inputs" to feel normal.