Can ADHD Cause Anxiety and Overthinking?
Here’s What’s Really Going On

If your brain never seems to switch off looping through worries, replaying conversations, or spiralling into “what ifs” at 2am you’re not imagining it. There’s a real, science-backed reason why ADHD and anxiety so often show up together.

What is ADHD, really?

Most people picture ADHD as a hyperactive kid who can’t sit still in class. But ADHD Attention Deficit Hyperactivity Disorder is far more nuanced than that. It’s a neurodevelopmental condition that affects how your brain regulates attention, impulse control, and emotion.

Adults with ADHD often describe it less as “can’t focus” and more as “can’t control what I focus on.” And that loss of control? It’s a perfect breeding ground for anxiety.

Research consistently shows that 50% or more of adults with ADHD also have a co-occurring anxiety disorder making it one of the most common combinations in mental health

So, can ADHD actually cause anxiety?

Yes though it’s a bit more layered than a simple cause-and-effect. ADHD doesn’t automatically “give” you an anxiety disorder. But living with an unmanaged or undiagnosed ADHD brain creates conditions where anxiety absolutely thrives. Here’s why:

1. Executive dysfunction makes daily life feel overwhelming

Executive function is the brain’s management system it handles planning, prioritising, starting tasks, and managing time. ADHD disrupts this significantly. When simple tasks like paying a bill or replying to an email feel monumental, it’s natural to feel a constant background hum of dread and worry. Over time, that hum becomes anxiety.

2. Rejection Sensitive Dysphoria (RSD)

This one doesn’t get talked about enough. Many people with ADHD experience RSD an intense emotional reaction to the perception of criticism or rejection. Even a slightly curt text from a friend can send the ADHD brain into a spiral of “Did I do something wrong? Are they mad at me?” That spiral? That’s anxiety and it can be crippling.

3. Years of “failing” takes a toll

Before diagnosis, many people with ADHD spend years being told they’re lazy, scattered, or not trying hard enough. That repeated experience of falling short despite genuinely trying builds a deep undercurrent of anxiety. You start anticipating failure before you’ve even begun.

“Living with undiagnosed ADHD is like running a marathon in shoes two sizes too small and then being told you’re just not a very good runner.”

Why does ADHD cause overthinking specifically?

Overthinking isn’t just a quirky habit it’s an almost inevitable feature of the ADHD brain

The ADHD brain struggles to “park” thoughts

A neurotypical brain can file a thought away: “I’ll deal with that tomorrow.” The ADHD brain doesn’t have a reliable filing system. Thoughts stay in the foreground, looping and demanding attention. This is why falling asleep can feel impossible your brain is still actively processing everything that happened today, plus everything that might happen tomorrow.

Working memory issues keep dragging you back

Working memory the mental sticky note where you hold information temporarily is often impaired in ADHD. When you’re worried you’ll forget something important, your brain tries to compensate by thinking about it. Constantly. Even when you don’t want it to.

Hyperactivity goes internal

In many adults with ADHD, especially women, hyperactivity doesn’t look like bouncing off walls it looks like an internal mental restlessness. Thoughts racing, jumping between topics, never feeling mentally “still.” This is often mistaken for anxiety on its own, when it’s actually a core feature of ADHD.

Symptoms that look like both ADHD and anxiety

This is where things get genuinely tricky. Some symptoms straddle both conditions, which is one reason ADHD is so often misdiagnosed as anxiety disorder particularly in women and girls.

Symptom	How it shows up
Trouble concentrating	Hard to focus due to worry or mental noise
Restlessness	Can’t sit still or feel mentally calm
Procrastination	Avoiding tasks due to overwhelm or fear of failure
Sleep difficulties	Mind won’t switch off at bedtime
Irritability	Frustration from constant mental exhaustion
Racing thoughts	Mind won’t slow down, especially at night

Because these symptoms overlap so heavily, it’s really important to see a professional who understands both conditions. Treating only anxiety without addressing the underlying ADHD often means you’re managing symptoms without ever fixing the root cause.

What can actually help: practical strategies

Managing ADHD-related anxiety and overthinking isn’t about “thinking less” or “just relaxing.” It requires working with your brain, not against it.

1. Get a proper dual assessment – If you suspect both ADHD and anxiety, push for evaluation of both. The treatment path for ADHD-driven anxiety is different from anxiety disorder alone and the order in which you treat them matters

2. Externalise your thinking – Brain dumps, voice memos, sticky notes get thoughts out of your head and into the physical world. This reduces the mental load your brain feels it has to constantly maintain.

3. Create structure but make it flexible – Rigid schedules often backfire with ADHD. Time-blocking with built-in buffers and self-compassion for when plans shift tends to work much better.

4. Try ADHD-specific therapy (CBT or DBT) – Standard CBT for anxiety doesn’t always land with ADHD brains. Look for therapists who specialise in neurodivergent clients the approach is meaningfully different.

5. Talk to a psychiatrist about medication options – For many people, treating ADHD with stimulant or non-stimulant medication also significantly reduces anxiety because you’re addressing the root dysregulation, not just the symptom.

6. Build a “worry window.” – Set aside 15 minutes a day where you’re allowed to overthink freely. Outside that window, when anxious thoughts arrive, tell your brain “noted we’ll deal with that at 5pm.” Sounds weird, but it works.

Frequently asked questions

Can ADHD medication make anxiety worse?

For some people, stimulant medications can initially heighten anxiety or increase heart rate. This is why it’s so important to work with a psychiatrist who knows your full picture. Often the dose is adjusted, or a non-stimulant like Strattera (atomoxetine) is considered instead. For many, treating the ADHD actually calms the anxiety.

Why do I overthink at night specifically?

Daytime stimulation often gives the ADHD brain just enough input to stay regulated. At night, when external stimulation drops, the brain looks for its own stimulation and lands on thoughts, worries, and “what ifs.” This is incredibly common with ADHD and often improves significantly with proper treatment.

Can you have ADHD with anxiety but no hyperactivity?

Yes. The inattentive presentation of ADHD (previously called ADD) doesn’t involve visible hyperactivity. People with this type often fly under the radar for years. Internally, though, the mental restlessness and anxiety can be just as intense.

Is it ADHD or anxiety or both?

It can absolutely be both. Research suggests roughly half of people with ADHD also have a diagnosable anxiety disorder. The key distinction: ADHD anxiety usually stems from dysregulation and overwhelm, whereas primary anxiety disorder tends to involve more generalised, pervasive worry patterns. A mental health professional can help you tease these apart.

Is ADHD-related overthinking the same as OCD?

They can look similar on the surface but are different conditions. OCD involves intrusive thoughts and compulsive behaviours driven by a specific anxiety loop. ADHD overthinking is more scattered and tied to working memory struggles. That said, ADHD and OCD can co-occur, which is another reason proper assessment matters.

The bottom line

Yes ADHD absolutely can cause anxiety and overthinking. Not because there’s anything fundamentally broken in you, but because living in a world that isn’t designed for your brain type creates very real psychological stress over time.

The encouraging part? Once you understand what’s actually driving the anxiety, you can start addressing it at the source. With the right support whether that’s therapy, medication, practical strategies, or simply the validation of finally having a name for what you’ve been experiencing things genuinely can get better.

If any of this has resonated with you, consider speaking to your GP or a mental health professional about a comprehensive ADHD evaluation. You deserve support that actually fits your brain.

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Can ADHD Cause Anxiety and Overthinking?Here’s What’s Really Going On