1. Clinical evaluations have been made upon 1,450 trials with chlorpromazine, a combination of Thorazine and reserpine, Frenquel, Pacatal, and Serpasil.2. The patient material utilized for this study consisted of a very chronic, inpatient population of a state hospital with a very high percentage of schizophrenic reactions.3. All 5 compounds tested appear to be of benefit in some respect, but not to the same degree.4. Thorazine appears to be the most generally effective, and Frenquel the least.5. All drugs appear most effective in the treatment of early cases and least effective in the very chronic.6. High dosages of drugs do not appear to provide any benefit over and above the benefit derived from moderate dosage.7. The incidence of side-effects is highest with Thorazine and Thorazine combined with reserpine and lowest with Frequel.8. Combined Thorazine-reserpine therapy does not follow the prediction that the good effects of each drug would be potentiated and the ill effects merely additive. Thorazine-reserpine produces a prohibitively high incidence of serious untoward effects.9. Patients who do not respond to one drug may respond to another. Patients who respond moderately to one drug may respond maximally to another.10. No single diagnostic category seems to respond outstandingly to any one drug.11. Hyperactivity, combativeness and tension respond best to ataraxics. The response of insight, affect, judgment, and realistic planning is disappointing.12. Our results support the concept that ataractic drugs are of value in the treatment of psychiatric disorders.