What is ICD-10 code F41.9?

F41.9 is the ICD-10-CM code for Anxiety disorder, unspecified. The FY2027 tabular list includes "Anxiety NOS" (not otherwise specified) under it. It sits in category F41 (Other anxiety disorders) alongside F41.0 (panic disorder), F41.1 (generalized anxiety disorder), F41.3 (other mixed anxiety disorders), and F41.8 (other specified anxiety disorders).

Is F41.9 a billable ICD-10-CM code?

Yes, F41.9 is a billable code in the FY2027 ICD-10-CM code set (effective October 1, 2026). It has no further subdivisions. Billable does not mean preferred, though; when the record supports a specific anxiety diagnosis, the specific code should be reported instead.

When should F41.9 be used?

The ICD-10-CM Official Guidelines for Coding and Reporting say codes titled "unspecified" are for use when the information in the medical record is insufficient to assign a more specific code. F41.9 fits an encounter where clinically significant anxiety is documented but the type (generalized, panic, social, phobic) has not yet been established, for example at a first visit before a full assessment.

What is the difference between F41.9 and F41.1?

F41.1 (Generalized anxiety disorder) is a specific diagnosis with its own criteria, including persistent, hard-to-control worry over months. F41.9 is the unspecified code for anxiety whose type has not been established. Once an assessment confirms generalized anxiety disorder, F41.1 replaces F41.9 on later claims.

What is the difference between F41.9 and F41.8?

Under the official guidelines, "other specified" codes are for when the record gives detail for which no specific code exists, while "unspecified" codes are for when the record lacks detail. F41.8 (Other specified anxiety disorders) includes terms such as mixed anxiety and depressive disorder. F41.9 is for anxiety documented without that detail.

Does anxiety after a stressor or trauma go under F41.9?

Usually not. Category F41 carries an Excludes2 note for anxiety in acute stress reaction (F43.0) and in transient adjustment reaction (F43.2). When anxiety follows an identifiable stressor, consider the adjustment disorder codes, such as F43.22 (Adjustment disorder with anxiety) or F43.23 (Adjustment disorder with mixed anxiety and depressed mood).

What scale is used to screen when F41.9 is coded?

The GAD-7 is the common choice. In its validation study, a cut point optimized sensitivity (89%) and specificity (82%) for generalized anxiety disorder (Spitzer et al., 2006). A follow-up primary care study found the GAD-7 and its two core items (GAD-2) performed well as screeners for generalized anxiety, panic, social anxiety, and post-traumatic stress disorder (area under the curve 0.80 to 0.91; Kroenke et al., 2007), which suits an unspecified anxiety presentation.

What should be ruled out before coding anxiety?

Medical conditions, medications, and substances can cause anxiety directly. The Merck Manual lists conditions such as cardiac arrhythmias, hyperthyroidism, asthma, COPD, and pheochromocytoma; medications for asthma, ADHD, and seizures; and substances such as caffeine and cocaine, plus withdrawal from alcohol or sedatives. Anxiety from a medical condition is coded F06.4; substance-induced anxiety uses the substance-specific codes in F10 to F19.

Can a client stay on F41.9 long term?

The guidelines ask that each encounter be coded to the level of certainty known at that encounter. F41.9 is appropriate while the anxiety type is unclear, but as assessment and measurement add detail, the record should support a more specific code. Documenting why the type is still unclear keeps the code choice defensible.

How is anxiety treated?

According to the Merck Manual, psychotherapy and medications are effective for most anxiety disorders, particularly together. Cognitive behavioural therapy has the strongest evidence among psychosocial treatments, and SSRIs are generally considered first-line medications, with response often taking six or more weeks. Exercise, sleep, and limiting caffeine can also help.

F41.9ICD-10-CMAnxiety Disorder, Unspecified

Official ICD-10-CM descriptor: Anxiety disorder, unspecified · Category header, not billable: use a more specific code

Clinically significant anxiety documented without enough information to assign a more specific anxiety disorder code. The FY2027 tabular list includes "Anxiety NOS" under this code.

Recommended screener

Validated screener
Generalized Anxiety Disorder 7-item Scale (GAD-7)
View scale

DSM-5-TR diagnostic criteria summary

F41.9 is a residual code rather than a criteria set of its own. It is used when:

Anxiety is clinically significant, causing distress or impairment in daily functioning.
The record does not support a more specific code, such as F41.0 (panic disorder), F41.1 (generalized anxiety disorder), F40.10 (social phobia), or a specific phobia in F40.2.
Other causes have been considered, including anxiety due to a medical condition (F06.4) and substance- or medication-induced anxiety.

DSM-5-TR lists "unspecified anxiety disorder" among its anxiety disorders, and the FY2027 ICD-10-CM tabular list includes "Anxiety NOS" under F41.9. The ICD-10-CM Official Guidelines state that unspecified codes are acceptable, even necessary, when they most accurately reflect what is known at the encounter, and that it would be inappropriate to choose a specific code the record does not support.

Source: Centers for Disease Control and Prevention / National Center for Health Statistics. ICD-10-CM Tabular List and Official Guidelines for Coding and Reporting, FY2027, Sections I.A.9 and I.B.18.

Differential diagnosis

Generalized Anxiety Disorder (F41.1), persistent, hard-to-control worry across many areas of life.
Panic Disorder (F41.0), recurrent unexpected panic attacks with ongoing concern about further attacks.
Social Anxiety Disorder (F40.10), fear centred on social or performance situations.
Other Specified Anxiety Disorders (F41.8), anxiety with documented detail that has no specific code, such as mixed anxiety and depressive disorder.
Adjustment Disorder with Anxiety (F43.22) or with Mixed Anxiety and Depressed Mood (F43.23), anxiety in response to an identifiable stressor.
Acute Stress Reaction (F43.0) and PTSD (F43.10), anxiety after a traumatic event.
Anxiety Disorder Due to Known Physiological Condition (F06.4), for example from hyperthyroidism or cardiac arrhythmia.

Common comorbidities

Anxiety often co-occurs with depression. In the GAD-7 validation study, anxiety and depression symptoms frequently co-occurred but were confirmed as distinct dimensions with independent effects on functioning (Spitzer et al., 2006). Screen for depression alongside anxiety, and code each condition that meets criteria. See the PHQ-9 vs GAD-7 comparison for overlapping anxious-depressive presentations.

Documentation patterns

Initial visit: GAD-7 score, the anxiety symptoms observed, what has been ruled out (medical, substance), and why a specific anxiety diagnosis cannot yet be made.
Follow-up visits: re-administer the GAD-7 and record new detail (worry pattern, panic attacks, social triggers) that may support moving to a specific code.
Comorbidities: PHQ-9 co-administered for depressive symptoms; both codes recorded if criteria are met.

Sources

Centers for Disease Control and Prevention, National Center for Health Statistics. (2026). ICD-10-CM Tabular List of Diseases and Injuries, FY2027 (effective October 1, 2026). https://ftp.cdc.gov/pub/Health_Statistics/NCHS/Publications/ICD10CM/2027/
Centers for Disease Control and Prevention, National Center for Health Statistics. (2026). ICD-10-CM Official Guidelines for Coding and Reporting, FY2027, Sections I.A.9 and I.B.18.
Spitzer, R. L., Kroenke, K., Williams, J. B. W., & Löwe, B. (2006). A brief measure for assessing generalized anxiety disorder: The GAD-7. Archives of Internal Medicine, 166(10), 1092–1097.
Kroenke, K., Spitzer, R. L., Williams, J. B. W., Monahan, P. O., & Löwe, B. (2007). Anxiety disorders in primary care: Prevalence, impairment, comorbidity, and detection. Annals of Internal Medicine, 146(5), 317–325.
Barnhill, J. W. (2026). Overview of anxiety disorders. Merck Manual Professional Edition.

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Frequently asked questions

What is ICD-10 code F41.9?
F41.9 is the ICD-10-CM code for Anxiety disorder, unspecified. The FY2027 tabular list includes "Anxiety NOS" (not otherwise specified) under it. It sits in category F41 (Other anxiety disorders) alongside F41.0 (panic disorder), F41.1 (generalized anxiety disorder), F41.3 (other mixed anxiety disorders), and F41.8 (other specified anxiety disorders).
Is F41.9 a billable ICD-10-CM code?
Yes, F41.9 is a billable code in the FY2027 ICD-10-CM code set (effective October 1, 2026). It has no further subdivisions. Billable does not mean preferred, though; when the record supports a specific anxiety diagnosis, the specific code should be reported instead.
When should F41.9 be used?
The ICD-10-CM Official Guidelines for Coding and Reporting say codes titled "unspecified" are for use when the information in the medical record is insufficient to assign a more specific code. F41.9 fits an encounter where clinically significant anxiety is documented but the type (generalized, panic, social, phobic) has not yet been established, for example at a first visit before a full assessment.
What is the difference between F41.9 and F41.1?
F41.1 (Generalized anxiety disorder) is a specific diagnosis with its own criteria, including persistent, hard-to-control worry over months. F41.9 is the unspecified code for anxiety whose type has not been established. Once an assessment confirms generalized anxiety disorder, F41.1 replaces F41.9 on later claims.
What is the difference between F41.9 and F41.8?
Under the official guidelines, "other specified" codes are for when the record gives detail for which no specific code exists, while "unspecified" codes are for when the record lacks detail. F41.8 (Other specified anxiety disorders) includes terms such as mixed anxiety and depressive disorder. F41.9 is for anxiety documented without that detail.
Does anxiety after a stressor or trauma go under F41.9?
Usually not. Category F41 carries an Excludes2 note for anxiety in acute stress reaction (F43.0) and in transient adjustment reaction (F43.2). When anxiety follows an identifiable stressor, consider the adjustment disorder codes, such as F43.22 (Adjustment disorder with anxiety) or F43.23 (Adjustment disorder with mixed anxiety and depressed mood).
What scale is used to screen when F41.9 is coded?
The GAD-7 is the common choice. In its validation study, a cut point optimized sensitivity (89%) and specificity (82%) for generalized anxiety disorder (Spitzer et al., 2006). A follow-up primary care study found the GAD-7 and its two core items (GAD-2) performed well as screeners for generalized anxiety, panic, social anxiety, and post-traumatic stress disorder (area under the curve 0.80 to 0.91; Kroenke et al., 2007), which suits an unspecified anxiety presentation.
What should be ruled out before coding anxiety?
Medical conditions, medications, and substances can cause anxiety directly. The Merck Manual lists conditions such as cardiac arrhythmias, hyperthyroidism, asthma, COPD, and pheochromocytoma; medications for asthma, ADHD, and seizures; and substances such as caffeine and cocaine, plus withdrawal from alcohol or sedatives. Anxiety from a medical condition is coded F06.4; substance-induced anxiety uses the substance-specific codes in F10 to F19.
Can a client stay on F41.9 long term?
The guidelines ask that each encounter be coded to the level of certainty known at that encounter. F41.9 is appropriate while the anxiety type is unclear, but as assessment and measurement add detail, the record should support a more specific code. Documenting why the type is still unclear keeps the code choice defensible.
How is anxiety treated?
According to the Merck Manual, psychotherapy and medications are effective for most anxiety disorders, particularly together. Cognitive behavioural therapy has the strongest evidence among psychosocial treatments, and SSRIs are generally considered first-line medications, with response often taking six or more weeks. Exercise, sleep, and limiting caffeine can also help.