ADHD (F90.0, F90.1, F90.2) is a neurodevelopmental condition of attention and impulse control with onset before age 12; generalized anxiety disorder (F41.1) is pervasive worry. They overlap on restlessness and concentration problems and frequently co-occur, in which case you code both.
Quick Comparison
Placed side by side, ADHD and generalized anxiety diverge on onset, on what is at the core of the presentation, and on what is actually driving the restlessness and concentration problems that make them look alike.
| Feature | ADHD (F90.x) | Anxiety (F41.1) |
|---|---|---|
| Onset | Symptoms present before age 12 | Can begin at any age; often later |
| Core feature | Attention and impulse control; a neurodevelopmental trait | Pervasive, excessive worry |
| Restlessness driver | Hyperactivity and difficulty sitting still, independent of worry | Physical tension and keyed-up feeling driven by worry |
| Concentration problem cause | Difficulty sustaining attention regardless of mood or worry | Worry crowds out attention; mind goes blank |
| ICD-10 code | F90.0 / F90.1 / F90.2 | F41.1 |
The core question: is the inattention there whether or not the person is worried? If attention problems exist independently of worry and predate it, that points to ADHD. If they rise and fall with the worry, that points to anxiety.
Where They Overlap
ADHD and generalized anxiety share a surface that makes them easy to confuse, and the overlap is why so many presentations get coded for one when the other is also present:
- Restlessness. ADHD hyperactivity and anxious keyed-up tension both look like a person who cannot sit still or settle.
- Concentration problems. Both conditions produce difficulty focusing and following through, though for different reasons.
- Sleep disruption. Racing thoughts in anxiety and a busy, hard-to-quiet mind in ADHD both interfere with falling asleep.
- Irritability and being on edge. Both can present with a short fuse and a sense of being overwhelmed by demands.
Because the presenting complaints are so similar, the differentiation has to rest on onset, pervasiveness, and what is driving the inattention rather than on the surface symptoms alone.
How to Tell Them Apart
Three questions separate ADHD from generalized anxiety:
Onset before age 12. ADHD is neurodevelopmental, so several inattentive or hyperactive-impulsive symptoms must have been present before age 12, typically with a childhood history across home and school. Generalized anxiety can begin at any age and often emerges later, so a clear adult onset with no childhood attention history argues against ADHD.
Pervasiveness across settings and time. ADHD symptoms are relatively stable traits present across most settings, regardless of whether the person is currently worried. Generalized anxiety worry waxes and wanes with stressors, and the concentration problems track with anxious periods rather than being constant.
Whether worry drives the inattention. This is the decisive question. In anxiety, the inattention is a downstream effect of worry: the mind goes blank or is crowded out by anxious thoughts. In ADHD, the inattention is present independent of worry and would be there even on a calm, low-stress day.
Do not force a choice when both fit. If a client has a clear childhood history of inattention that exists independent of worry and pervasive worry that predates and stands apart from the attention problems, both diagnoses may be warranted. Coding only one understates the clinical picture.
How to Code Each
ADHD is coded by presentation, and generalized anxiety has its own single code. Match the code to what the assessment supports:
| Code | Description | Notes |
|---|---|---|
| F90.0 | ADHD, predominantly inattentive type | Inattention without significant hyperactivity-impulsivity |
| F90.1 | ADHD, predominantly hyperactive-impulsive type | Hyperactivity-impulsivity without significant inattention |
| F90.2 | ADHD, combined type | Both inattentive and hyperactive-impulsive symptoms |
| F41.1 | Generalized anxiety disorder | Pervasive, free-floating worry across multiple domains |
For ADHD, choose the presentation: F90.0 when inattention dominates, F90.1 when hyperactivity-impulsivity dominates, and F90.2 when both are present. For generalized anxiety, use F41.1. Plain F90 is a non-billable category header and will be rejected for insufficient specificity.
When Both Are Present
ADHD and anxiety frequently co-occur; an anxiety disorder is present in roughly 30 percent of people with ADHD. When both conditions are genuinely present, there is no single combined code. You code both, for example F90.0 plus F41.1, and list the primary focus of treatment first.
- Do not collapse the two. Coding only the anxiety when ADHD is also present, or vice versa, understates the picture and can misdirect treatment.
- Order by focus of treatment. List the condition that is the primary focus of the current episode of care first, then the co-occurring diagnosis.
- Show your reasoning. Document the evidence for each diagnosis independently so the pairing supports medical necessity.
Documentation
Strong documentation should make the differentiation, and any co-occurrence, defensible:
Age of onset: for ADHD, note that symptoms were present before age 12 with a childhood history across settings such as home and school.
Pervasiveness: whether symptoms are stable across settings and time (pointing to ADHD) or wax and wane with worry (pointing to anxiety).
Driver of inattention: a brief note on whether the concentration problems exist independent of worry or are driven by it, which is the decisive differentiator.
Presentation for ADHD: which symptoms are present so the F90.0, F90.1, or F90.2 selection is supported.
Co-occurrence: when coding both, the independent evidence for each diagnosis and the primary focus of treatment.
Frequently Asked Questions
- Is it ADHD or anxiety?
- Start with two questions: when did the symptoms begin, and what drives the inattention. ADHD is a neurodevelopmental condition with symptoms present before age 12 and across settings; the inattention is there whether or not the person is worried. Generalized anxiety disorder is pervasive worry, and its concentration problems are driven by that worry, so they track with anxious periods. If attention problems predate the worry and exist independently of it, think ADHD; if the inattention only appears alongside worry, think anxiety. When both patterns are clearly present, you code both.
- Can you have both ADHD and anxiety?
- Yes, and it is common. An anxiety disorder co-occurs in roughly 30 percent of people with ADHD. There is no single combined code, so you bill both diagnoses, for example F90.0 plus F41.1, and list the primary focus of treatment first. Document how each condition presents so the pairing supports medical necessity.
- What is the ICD-10 code for ADHD?
- ADHD is coded by presentation: F90.0 for predominantly inattentive type, F90.1 for predominantly hyperactive-impulsive type, and F90.2 for combined type. Plain F90 is a category header and is not billable on its own; you must select the fourth-character code that matches the presentation.
- What is the code for anxiety?
- For generalized anxiety disorder the ICD-10-CM code is F41.1. Anxiety is a broad family, so F41.1 is specific to pervasive, free-floating worry across multiple domains. Other anxiety presentations use different codes, for example F41.0 for panic disorder and F40.10 for social anxiety disorder.
Differentiating ADHD from anxiety comes down to onset before age 12, pervasiveness across settings, and whether worry drives the inattention. Code ADHD by presentation (F90.0, F90.1, F90.2) and generalized anxiety as F41.1, and when both are truly present, code both.