Psychiatry is a branch of medicine which deals with the identification and treatment of mental illness. Psychology is the science of understanding, interpreting, and classifying the various aspects of human behavior. Clinical psychology is psychology practiced by a licensed professional with a Ph.D. or Psy. D. in psychology. The field of clinical psychology has developed and standardized a host of procedures and practices to detect, evaluate, and treat abnormal behavioral conditions and mental disorders.
Neuropsychology is a highly specialized discipline within the field of psychology.
The science of neuropsychology focuses on cognition, i.e., the ability of the mind and brain to think, reason, remember, learn, comprehend, etc. Clinical neuropsychology is practiced by a licensed psychologist specializing in neuropsychology. This specialty field has developed a variety of clinically standardized tests and procedures to evaluate the cognitive and functional effects of brain injury, brain damage, and organic brain disease. Neurology is a field encompassing the science and study of the human brain and nervous system and its diseases. The function and practice of a clinical neurologist differs substantially from that of a neuropsychologist.