Attention deficit disorder and allergy: a neurochemical model of the relation between the illnesses.

Empirical studies suggest that allergies play an etiological role in a small subgroup of children who suffer from attention deficit-hyperactivity disorder (ADHD). Research indicates that allergic reactions results in cholinergic hyperresponsiveness and beta-adrenergic hyporesponsiveness in the autonomic nervous system. Evidence is reviewed that similar imbalances in central nervous system cholinergic/adrenergic activity play a causal role in manic and depressive behaviors. It is hypothesized that allergic reactions engender cholinergic/adrenergic activity imbalances in the central nervous system, leading to poorly regulated arousal levels and ADHD behaviors in some children.