The present invention includes a system and method for computerized analysis of a patient's electroencephalogram (EEG) recorded by electrodes placed on the scalp, for the purpose of predicting patient response to medications and therapeutic agents commonly used in psychiatric practice. The prediction of the responses to medications (adverse, no effect, favorable outcome) is an important problem in the clinical practice of psychiatry. A growing number of therapeutic agents are available to the clinician but these agents generate variable responses when prescribed based solely on the patient's history and current symptoms. The present invention is used by physicians to improve patient outcome by selecting agents most likely to be effective for a given patient, using a standardized analysis of the digitized EEG and comparison of individual patient EEC data to a particular database of similar patients whose clinical outcome to pharmacotherapy is known.