Feeling foggy, slow and unable to concentrate can feel like an attention problem. Sometimes it is. Often, the real cause is fatigue from a medical or sleep problem, and treating that cause clears the fog.
Medical causes worth ruling out
- Anemia, which reduces oxygen delivery and causes tiredness
- Thyroid problems, especially an underactive thyroid
- Low vitamin B12, more common in older adults and with some medicines or stomach conditions
- Blood sugar problems, including diabetes
- Sleep apnea and other sleep disorders
- Depression, which commonly causes fatigue and slowed thinking
How fatigue and ADHD differ
Fatigue-related fog usually has a starting point and often comes with low energy, extra sleepiness or other physical symptoms. ADHD begins in childhood and usually shows signs back to school years, even when energy is good.
How we sort it out
Your provider asks about sleep, mood, energy and medical history, and when your history calls for it, orders basic blood tests or coordinates with your primary care provider. If an attention problem remains once other causes are addressed, ADHD testing and evaluation are the next step.
Request an ADHD evaluation if you want a thorough, careful workup. Read how ADHD testing works and what it costs first so you know what to expect.
This article is general health information and does not replace advice from your own provider.
Frequently Asked Questions
Common causes include anemia, an underactive thyroid, low vitamin B12, blood sugar problems, sleep apnea and depression. Side effects of some medicines can also contribute.
Yes. Fatigue from poor sleep or a medical problem can cause trouble focusing that looks like ADHD. ADHD begins in childhood, while fatigue-related fog usually has a recent starting point.
When your history calls for it, common tests include a complete blood count for anemia, a thyroid test, a blood sugar or A1C test and sometimes a vitamin B12 level.