Final answer:
The DSM is mainly used by mental health professionals in the United States, although its influence extends to other countries.
Step-by-step explanation:
The DSM (Diagnostic and Statistical Manual of Mental Disorders) is primarily used by professionals in the field of mental health within The United States. Created by the American Psychiatric Association, the DSM serves as a standardized system for diagnosing and classifying mental disorders, and it is periodically updated to reflect new research and clinical experience. Although it is an American publication, the DSM's influence extends to other countries, predominantly in North America, but it is not the primary diagnostic manual outside the U.S. In Europe, for example, many professionals prefer using the ICD (International Classification of Diseases) for diagnosis.