Diagnostic Codes: DSM-5 vs ICD-10

It is common for therapists entering private practice to begin to scrutinize diagnostic codes and wonder about the value and differences between the ICD-10 and DSM-5 codes. The similarities between the two sets and when to use them can be confusing, so we will be digging in to each of these diagnostic tools to help clarify the relationship and what their purposes are.

What is the DSM-5?

The DSM-5 is considered the most comprehensive and critical resource for mental health professionals today. The DSM is a manual for assessment and diagnosis of mental disorders, and is widely used by therapists, social workers, psychologists, and other behavioral and mental health professionals in treating their patients. The DSM does not include information or guidelines for treatment of any disorder, but focuses on assisting the healthcare provider in determining an accurate diagnosis and classification.

The original publication of the DSM in 1952 listed only 60 mental disorders.

The Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, was first published in 1952 and listed sixty mental health disorders. Its goal was primarily to create a single nomenclature for psychopathology as, at the time, several separate diagnostic systems were in use, none of which were cross-walked to match one another for reporting or treatment coordination. The APA recognized the issue and developed the DSM as a result.

Today, the DSM-5 boasts over 300 mental health disorders and has undergone major revisions throughout the last six decades.

The most recent version of the DSM (version 5) was published in 2013, and stands on the shoulders of more than 60 years of research and effort by hundreds of international experts in all aspects of mental health, with the purpose of improving mental health diagnoses, treatment, and research. The manual is intended to avoid diagnostic confusion and inequalities in practical diagnostic work, and therefore creates a common language for clinicians, and utilizes specific criteria to facilitate an objective assessment of symptom presentations.

What is ICD-10?

The ICD-10 is the 10th revision of a classification tool for medical diagnoses compiled by the World Health Organization (WHO). Formally known as the International Statistical Classification of Diseases and Related Health Problems (typically abbreviated to simply ICD), this medical classification list contains codes for diseases, signs and symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or diseases.

The widespread use of the ICD codeset by WHO member nations assists in the tracking and reporting on diseases worldwide.

This international codeset dates back to 1983 when extensive research began. The work was further supported by the World Health Assembly in 1990, and introduced in 1994 by WHO member nations. The current version, ICD-10, represents the 10th revision of this system, which is used extensively across the world; nearly 30 countries use ICD-10 for healthcare reimbursement purposes in their respective health systems, while approximately 120 countries use ICD-10 to report on diagnostic and medical statistics (including cause of death reports).

Here in the US, the National Center for Health Statistics maintains the US version of ICD-10. With permission of the WHO, the US utilizes a modified version of ICD-10, called ICD-10 CM, which stands for Clinical Modification. The ICD-10 CM has over 70,000 codes and its codes are required for use in healthcare claims submission for purposes of reporting and reimbursement. The US transitioned from ICD-9 to ICD-10 in October 2015, after several years of delay.

While mental health professionals will use DSM-5 codes for diagnostic and treatment purposes, ICD-10 codes must always be used for reimbursement.

Why Are There Two Code Sets?

It may appear that the DSM-5 is redundant and unnecessary in light of the ICD-10 CM coding system. However, the DSM-5 gives mental health professionals criteria and definitions to classify diseases through a common language, while ICD-10 assigns a code that is used for reimbursement in claims processing. It is also important to note that the DSM-5 is strictly intended for mental disorders. While ICD-10 includes those same conditions, it contains conditions and diseases related to the entire human physiology, and does not cover mental disorders in the same depth as the DSM-5 does. This represents one of the most important differences between ICD-10 and DSM-5.

Since the DSM-5 and ICD-10 are separate lists and are maintained by separate entities, there are at times disconnects between the two sets; not all diagnoses that appears in the DSM-5 have a direct correlation in the US version of ICD-10 (e.g. dementia, which is noted in DSM-5 as a neurocognitive disorder, which is not how ICD-10 characterizes dementia). However, in most cases, the nomenclature is quite similar. The important practical difference between the sets is that while therapists will use the DSM-5 codes for diagnostic and treatment purposes, ICD-10 codes are used for reimbursement: DSM-5 codes are not strictly reimbursable by insurance payers, therapists must submit ICD-10 codes on insurance claims or their claims will be rejected.

Looking Forward

While in the future, as the ICD codeset continues to be developed and becomes more in-depth and detailed in its descriptions of diseases, the work of the APA through the DSM may become redundant. As these diagnostic tools are updated, the US may be able to incorporate more nuance and description into the US-specific versions of future ICD-CM editions to allow a more streamlined and simplified publication for healthcare professionals that assists mental and behavioral healthcare professionals in their crucial work to properly diagnose and treat mental disorders.

For the foreseeable future, mental health providers will continue to use the DSM-5 to identify and diagnose mental disorders, while using the ICD-10 CM codes to bill for reimbursement. To read about the most commonly used diagnostic codes within KASA by our users, click here.