Have you heard the claim, “People with ADHD have higher cortisol all the time—they’re stuck in fight-or-flight”?
It’s a neat, simple explanation that fits perfectly into a marketing hook: Unfortunately, it’s not what the research shows.
The truth is more complicated—and more interesting. ADHD and cortisol don’t have a one-size-fits-all relationship. Depending on your age, the time of day, the type of stress, and whether you have other conditions alongside ADHD, your cortisol pattern could be lower, higher, or about the same as someone without ADHD.
Let’s unpack the science!
What is cortisol?
Cortisol is a hormone released by your adrenal glands as part of the body’s main stress response system known as the hypothalamic-pituitary-adrenal, or HPA axis.
It follows a daily rhythm:
Highest in the morning (the Cortisol Awakening Response, or CAR) to help you wake up and feel alert.
Gradually drops through the day, reaching its lowest point late at night.
Cortisol also spikes temporarily in response to stress: a normal, adaptive reaction. Over time, too many cortisol spikes—or if our cortisol stays elevated for too long—can lead to blunted reactivity or lower baseline cortisol.
What does the research say about ADHD and cortisol?
While you may have heard that people with ADHD are more likely to have higher cortisol, many studies actually show that people with ADHD have lower baseline cortisol. The implications of this are complex, which we’ll explore in more detail after reviewing the research.
1. Morning cortisol is often lower in people with ADHD
Meta-analysis findings show:
- Lower morning cortisol in youth with ADHD compared to typically developing peers
- Lower total cortisol output across the day
- Genetic evidence suggests a reverse causal relationship—ADHD may contribute to reduced morning cortisol, but reduced morning cortisol does not seem to lead to ADHD.
2. Stress reactivity is mixed—and depends on the situation.
While baseline cortisol may be lower, stress responses vary:
- Some adults with ADHD have shown a stronger cortisol spike than those without ADHD during challenging tasks, especially during anticipation and right after the stressor. Studies show this spike is also associated with stress perception, meaning people who feel like they have more stressors in life seem to experience those spikes.
- Other studies—particularly for people with ADHD combined with oppositional defiant disorder (ODD) or inattentive subtype—show a blunted stress response.
This variability means the HPA axis in ADHD isn’t simply “over” or “under” active—it can respond in opposite ways depending on the person and the context.
What does this mean?
- Morning cortisol: Often lower in ADHD
- Daily rhythm: Can have fewer highs and lows, but not always
- Stress response: Can be blunted, exaggerated, or normal depending on comorbidities, types of stress, and individual biology
Realistically, we don’t understand enough about cortisol and ADHD to make any conclusive remarks, but it’s safe to say ADHD does not automatically mean “high cortisol all the time.”
We don’t know if the average ‘lower cortisol’ is a feature of ADHD or if it is more connected to over-activation of fight-or-flight responses. We also don’t know enough about how it affects subtypes and the overlap with other conditions.
Why this matters
Marketing that aims to frame ADHD as a constant fight-or-flight state often sells “cortisol-lowering” supplements or lifestyle plans. But if your baseline cortisol is already low, further reducing it might not help—and could make you feel worse.
A more useful approach is learning how to regulate your cortisol:
- Support healthy morning cortisol levels (light exposure, consistent wake times)
- Manage anticipatory anxiety and improve stress recovery
- Identify personal triggers for both over- and under-activation of your stress response
- Create consistency in your chaos: eat three meals a day, exercise regularly, etc.
If you read that and thought, “Well, that sounds impossible,” I created two eBooks—The ADHD Guide to Interoception and The ADHD Guide to Nervous System Regulation—with you in mind. These resources teach you how to finally understand your body’s individual needs through a neurodivergent lens while giving you tools to improve how your body responds to stress.
Whether you’re a therapist or you have ADHD yourself, purchase the bundle to finally feel like your body came with a user’s manual.
ADHD and cortisol have a complex relationship. The best way to understand your own stress biology is through a combination of self-awareness, professional evaluation, and context. The key is developing the internal awareness and the skills to understand what state your body is in.
