THE THEORETICAL PRINCIPLES OF ORTHOMOLECULAR PSYCHIATRY STEM FROM THE INTERRELATIONSHIP BETWEEN THE INDIVIDUAL AND TWO ENVIRONMENTS: THE PSYCHOSOCIAL ENVIRONMENT AND THE BIOCHEMICAL ENVIRONMENT. THE ROLES OF INFECTIONS, MALNUTRITION, AND ALLERGIES IN ALTERING BRAIN FUNCTION ARE DESCRIBED. THE PSYCHOLOGICAL STATES AFFECTING BRAIN FUNCTION ARE PERCEPTION, THOUGHT, FEELING (OR MOOD), AND BEHAVIOR. THE INTERACTION BETWEEN BIOLOGICAL AND PSYCHOSOCIAL IMBALANCES IS DISCUSSED FOR SCHIZOPHRENIC SYNDROMES, ANTIOSOCIAL BEHAVIOR, AND BIZARRE CRIMINAL ACTS. NUTRITION, SUPERNUTRITION, AND BORDERLINE MALNUTRITION ARE DISCUSSED IN TERMS OF THEIR AFFECTS ON THE BIOCHEMICAL ENVIRONMENT. THE THREE MOST COMMON FORMS OF CRIMINALLY RELATED MALNUTRITION ARE THE VITAMIN B DEPENDENCIES, THE SACCHARINE DISEASES (RELATIVE HYPOGLYCEMIAS), AND THE CEREBRAL ALLERGIES. THE NEED FOR AN ADEQUATE BIOCHEMICAL ENVIRONMENT AS WELL AS AN ADEQUATE SOCIAL ENVIRONMENT IS EMPHASIZED. THE CHAPTER CONTAINS NUMEROUS CASE HISTORIES AND REFERENCES. (GLR)