Co-occurring conditions
Short answer
Co-occurring conditions, also called coexisting conditions or comorbidities, are two or more health conditions present in the same person at the same time. Health agencies say ADHD often co-occurs with conditions such as anxiety, depression, sleep problems and learning disorders. Because some of these can also look like ADHD, evaluations try to identify what explains what.
When you read about adult ADHD, you will often see it discussed alongside other conditions. The term co-occurring is the tidy way of saying more than one thing can be true at once.
Three words, one idea
Co-occurring, coexisting and comorbid are used almost interchangeably. Each describes conditions that appear together in one person. None of them says that one condition caused the other.
Co-occurring conditions can also change how each one feels. Poor sleep can make inattention worse, and ongoing struggles with attention can feed worry or low mood. Untangling that loop is part of why evaluations take time.
What the agencies list
Overlap versus look-alikes
Here is the tricky part. Some conditions can sit alongside ADHD, and the same conditions can also produce symptoms that resemble it. Poor sleep, for example, can both coexist with ADHD and on its own make concentration hard.
For example, imagine someone with long-standing anxiety who has always assumed it explains their scattered focus. An evaluation might conclude that anxiety accounts for it, or that something else is present as well. Only a careful history can tell those stories apart.
Why evaluations look for them
What the screener cannot sort out
The ASRS v1.1 Screener asks about ADHD-related experiences only. It cannot tell whether a positive screen reflects ADHD, another condition, or several things at once. That is exactly the work of a clinical evaluation, and it is a good reason to mention every health condition and medication at an appointment.
If you already have a diagnosis such as anxiety or depression, it is still reasonable to raise attention concerns. Having one condition does not rule out another, and a clinician who knows your full history is best placed to consider both.
Keeping a simple list of past diagnoses, current conditions and medications makes this part of an appointment much easier.
A starting point for your next step.
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What conditions commonly co-occur with ADHD?
Health agencies mention anxiety, depression, sleep problems, learning disorders, disruptive behavior and addictions, among others.
Does having anxiety mean I do not have ADHD?
No. The two can occur together, and anxiety can also cause similar symptoms. A clinician can help work out which applies.
Is comorbidity the same as co-occurring?
Yes, in everyday use. Both describe two or more conditions present in the same person at the same time.
Sources
Source check: 2026-10-28. No medical review has occurred.
- NIMH, Attention-Deficit/Hyperactivity Disorder
- NHS, Attention deficit hyperactivity disorder (ADHD) in adults
- CDC, ADHD in Adults
- NICE guideline NG87, Attention deficit hyperactivity disorder: diagnosis and management
Published 2026-10-28. Factual source check: ADHDFalcon editorial team, factual source check, 2026-10-28. No medical review has occurred.