Mental Health ICD-10 Cheat Sheet

As a therapist, you may find the billing and claims submission process cumbersome. And for good reason: billing is complex due to the requirements of insurance companies that want detailed justification for the services you’re providing. In addition to the CPT services codes that you’ll bill for, you must also include ICD-10 diagnoses codes in your claims. In this post, we explore a bit of background on the ICD-10 and offer a cheat sheet for mental health ICD-10 codes that you can use as a reference. 

What is the ICD-10 Exactly?

Before we dive into the specifics of how the ICD-10 is laid out and share the codes applicable to mental health, here’s what you should know about the code set to give you a broader understanding. 

“ICD” stands for International Classification of Disease and is the title of the classification tool for medical diagnoses compiled by the World Health Organization (WHO). It was originally designed to help medical professionals worldwide communicate with one another about various diseases in an effort to cooperate in their efforts, particularly in cases of epidemics and pandemics. Now it’s used for a variety of purposes, including insurance billing.

The WHO updates the ICD periodically and the current version is the ICD-10. This is a worldwide reference, so the U.S. has developed its own clinical modification (ICD-10-CM) for use in this country. While the ICD-10-CM is based on the WHO’s ICD-10 set, there are a few unique differences. (Typically, when people in the U.S. refer to the ICD-10, they’re talking about the ICD-10-CM.) The U.S. version has over 70,000 different codes that describe diseases, signs and symptoms, abnormal findings, complaints, and external causes of injury or diseases. These codes are used in the healthcare claims submission process for purposes of reporting and reimbursement — they help provide justification for providing a client with the services you did.

How the ICD-10 Mental Health Codes Are Organized: G, Z, and F Codes

The mental health ICD-10 codes are organized into three primary categories: G, Z, and F. 

The G codes comprise diseases of the nervous system. The Z codes describe situations where the client doesn’t have a specific disorder but services are required anyway, such as if a client has a personal history of psychological trauma or if an authority body has requested a general psychiatric examination for someone. The F codes make up the majority of the mental health ICD-10 codes.

ICD-10 Codes for Mental Health Cheat Sheet

While there are many codes that may conceivably be used in healthcare situations, you won’t encounter all of them in your therapy practice. You’re unlikely to encounter the G codes since these are typically dealt with in a medical setting, but we’ve included the ones in this cheat sheet that you may come across. The list also includes the Z codes you’re likely to encounter. Since the F category is the most robust, we’ve included the most common F codes in this list, although you may encounter others that are less common. You can find a complete list of the major F subcategories here

Common G Codes

  • G20 (Parkinson's disease)
  • G30 (Alzheimer's disease)
  • G90 (disorders of autonomic nervous system)

Common Z Codes

  • Z00.4 (general psychiatric examination, not elsewhere classified)
  • Z03.2 (observation for suspected mental and behavioral disorders)
  • Z04.6 (general psychiatric examination, requested by authority)
  • Z09.3 (follow-up examination after psychotherapy)
  • Z13.3 (special screening examination for mental and behavioral disorders)
  • Z13.4 (special screening examination for certain developmental disorders in childhood)
  • Z50.4 (psychotherapy, not elsewhere classified)
  • Z54.3 (convalescence following psychotherapy)
  • Z63.0 (problems in relationship with spouse or partner)
  • Z71.1 (person with feared complaint in whom no diagnosis is made)
  • Z71.9 (counseling, unspecified)
  • Z81.8 (family history of other mental and behavioral disorders)
  • Z91.4 (personal history of psychological trauma, not elsewhere classified)

Common F Codes

  • F41.1 (generalized anxiety disorder)
  • F43.23 (adjustment disorder with mixed anxiety and depressed mood)
  • F43.22 (adjustment disorder with anxiety)
  • F33.1 (major depressive disorder, recurrent, moderate)
  • F43.20 (adjustment disorder, unspecified)
  • F41.9 (anxiety disorder, unspecified)
  • F43.21 (adjustment disorder with depressed mood)
  • F43.12 (post-traumatic stress disorder, chronic)
  • F34.1 (dysthymic disorder)
  • F43.10 (post-traumatic stress disorder, unspecified)
  • F32.1 (major depressive disorder, single episode, moderate)
  • F33.0 (major depressive disorder, recurrent, mild)
  • F32.9 (major depressive disorder, single episode, unspecified)
  • F90.2 (attention-deficit hyperactivity disorder, combined type)
  • F60.9 (personality disorder, unspecified)
  • F40.228 (other natural environment type phobia)
  • F43.25 (adjustment disorder w mixed disturb of emotions and conduct)
  • F06.1 (catatonic disorder due to known physiological condition)
  • F33.2 (major depressive disorder, recurrent severe without psychotic features)
  • F41.0 (panic disorder without agoraphobia)
  • F90.0 (attention-deficit hyperactivity disorder, predominantly inattentive type)
  • F32.0 (major depressive disorder, single episode, mild)
  • F42.2 (mixed obsessional thoughts and acts)
  • F84.0 (childhood autism)

Use as a Reference, But Understand the Nuances of the Codes

It’s important to note that you shouldn’t rely on the short descriptions of the codes only. Payers can be very particular when it comes to the codes they’re looking for to accompany specific services, and you’ll want to make sure you’re using the right ones. This is especially important as occasionally a therapist will use a code or set of codes that have a higher pay rate than the one they should be using (this practice is called upcoding or unbundling), and payers see this as abuse or fraud. However, with an understanding of the details of each diagnosis, this cheat sheet will serve as a reminder to jog your memory.

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