In a double-blind, placebo-controlled study, the efficacy and safety of alprazolam was investigated in childhood and adolescent anxiety disorders. Thirty patients (mean, 12.6 years) diagnosed with overanxious or avoidant disorders participated in the study. Evaluations included clinical, laboratory, cognitive, and qualitative EEG measurements. On a clinical global rating, there was no statistical difference between alprazolam and placebo. Relative to baseline EEG, acute alprazolam administration increased beta power in the right occipital lead, and chronic administration increased beta power in both leads. Alprazolam was well tolerated, and adverse effects were few, mild, and transient.