Final answer:
The primary tool used to classify and diagnose psychological disorders is the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association.
Step-by-step explanation:
The primary tool that is used to classify and diagnose psychological disorders is the Diagnostic and Statistical Manual of Mental Disorders (DSM), currently in its fifth edition (DSM-5). Published by the American Psychiatric Association, the DSM-5 is comprehensive and regularly updated to reflect advancements in the understanding of mental health. This manual provides standard criteria for the classification and diagnosis of mental disorders, enabling mental health professionals to communicate effectively and consistently about various psychological conditions.
While there are other tools such as the Minnesota Multiphasic Personality Inventory (MMPI) and the International Classification of Diseases (ICD) by the World Health Organization, the DSM-5 is the most widely used manual in the United States for psychiatric diagnoses. It is important to recognize that the DSM-5 is not without controversy, as the process of classifying and diagnosing mental disorders is complex and evolving.