When ADHD Symptoms Might Be Your Thyroid
Difficulty concentrating, forgetfulness, fatigue, irritability, brain fog. These symptoms could describe ADHD. They could also describe a thyroid disorder. Both an underactive and an overactive thyroid can affect concentration, memory, mood, and energy, which is why the two are easy to confuse.
This overlap matters for two reasons. First, people with undiagnosed thyroid problems may be misidentified as having ADHD. Second, and perhaps more commonly, people who have ADHD may also have a thyroid condition that's making their symptoms worse without anyone noticing.
The Symptom Overlap
Hypothyroidism (underactive thyroid) shares these symptoms with ADHD: mental fog, difficulty concentrating, forgetfulness, fatigue, sluggishness, and depressed mood. In the inattentive presentation of ADHD, the overlap is particularly easy to miss.
Hyperthyroidism (overactive thyroid) mimics different ADHD symptoms: restlessness, difficulty sitting still, irritability, racing thoughts, difficulty sleeping, and emotional reactivity. This can look very similar to the hyperactive-impulsive presentation of ADHD.
Research on whether thyroid problems are more common in people with ADHD is mixed, and most people with ADHD have normal thyroid function. But because the symptoms overlap, an untreated thyroid problem can make ADHD symptoms look or feel worse.
Getting the Right Diagnosis
A simple blood test can check your thyroid function. The basic panel includes TSH (thyroid-stimulating hormone), and if that's abnormal, free T3 and free T4 levels. This test is inexpensive, widely available, and can be done at any standard lab.
Consider getting your thyroid checked if:
- Your ADHD symptoms have worsened without an obvious cause
- You experience persistent fatigue beyond what's typical for you
- You've noticed changes in weight, temperature sensitivity, or hair/skin quality
- ADHD medication feels less effective than it used to
- You have a family history of thyroid disorders (they often run in families)
What to Do With the Results
- If your thyroid is normal: You've ruled out an important confounding factor. Your ADHD treatment plan can proceed with more confidence.
- If your thyroid is abnormal: Treatment with thyroid medication often improves the cognitive symptoms that overlap with ADHD. Some people find that treating their thyroid reduces their ADHD symptoms significantly, though it rarely eliminates them entirely if ADHD is also present.
- If you have both conditions: Both need treatment. Treating ADHD without addressing thyroid dysfunction (or vice versa) will leave you feeling only partially better. Work with your doctor to address both.
ADHD is diagnosed only when symptoms aren't better explained by another condition, so a thorough evaluation considers medical causes. Ask your doctor whether thyroid testing makes sense for you, especially if your symptoms are atypical, started in adulthood, or your treatment response is poor.