8 Adult ADHD Symptoms

Identifying the 8 Most Common Adult ADHD Symptoms

The most common symptoms of adult ADHD include difficulty focusing on tasks, impulsiveness, disorganization, forgetfulness, restlessness, difficulty completing tasks, frequent mood swings, and trouble managing stress. Recognizing these signs is crucial for seeking appropriate diagnosis and treatment, leading to improved daily functioning and quality of life.. 

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Alice Gendron

Founder of The Mini ADHD Coach

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The Most Common Symptoms of ADHD In Adults

For most adults with ADHD, you can’t always see the challenges that we navigate daily. But where it often goes unnoticed by others, you may not notice the signs yourself, especially if you don’t know what to look for. So what are the subtle signs that could be impacting your life? 

We’ll explore the most common symptoms of ADHD and share our own experiences. To start, we’ll look at:

  • An overview of adult ADHD symptoms
  • Zoning out or interrupting conversations 
  • Forgetfulness and losing things
  • Distractions and sensory overload
  • Impatience and ‘waiting time’
  • Impulsivity

Now that you know what to expect, let’s get into the nitty-gritty details of these symptoms.

An Overview of Adult ADHD 

Attention Deficit Hyperactivity Disorder (ADHD) is a complex neurodivergent condition that affects everyone differently. Two people, even with the same subtype of ADHD (there are three), can experience completely different symptoms.

Many of the common symptoms of ADHD  are caused by issues with the brain’s executive functions. This is the area of the brain related to mental skills like focus, attention, and memory.

Several known factors affect this (and likely some we don’t understand yet) like the brain’s effectiveness at producing chemicals, known as neurotransmitters, like dopamine and norepinephrine.  

Other factors include your personal circumstances and environmental factors, which is why you may notice your symptoms as an adult are different from when you were a child. 

You see, to be diagnosed with adult ADHD, you have to have had childhood symptoms, so naturally, adult symptoms are an evolution of childhood ADHD symptoms. 

Some adults may feel like their symptoms have faded over time. What this actually is is that you’ve either learned to manage the symptoms of this developmental disorder, or mask them. 

Childhood ADHD can seem more intense, but that’s because children are still growing and developing. They may also be experiencing learning disabilities and poor listening skills, which again, as we mature into young adults, we learn to manage.

You Asked…

What are 3 signs of ADHD in adults?

Three common signs of ADHD in adults include persistent inattention, hyperactivity, and impulsivity, affecting their work, relationships, and daily life.

Adult ADHD Diagnosis

Attention Deficit Hyperactivity Disorder (ADHD) is diagnosed using the 5th edition of the Diagnostic and Statistical Manual for mental health disorders (DSM-5), which is produced by the American Psychiatric Association.

To be diagnosed with adult ADHD:

  • You must experience at least five symptoms that meet the criteria for either hyperactivity-impulsivity or inattention.
  • The symptoms must be present in two or more settings and for at least six months to a disruptive extent.
  • These symptoms should be inappropriate for the person’s developmental level
  • The symptoms must have been present before the age of 12.

Your diagnosis journey can be challenging, as there are many comorbidities and mental disorders that can overlap with the symptoms of ADHD and lead to misdiagnosis, complicating the assessment and treatment process.

Many people, especially teenagers and young adults, are diagnosed with a mental health condition like depression and anxiety, long before they ever consider ADHD. And since they already have a diagnosis, they think they’re getting the right treatment for their condition, and often can’t understand why it’s not working.

This is because ADHD traits like lack of emotional dysregulation and mental hyperactivity (racing thoughts) can be experienced by those with mood disorders and anxiety disorders too.

If you are or have been, diagnosed with another condition, keep an open mind as you read through these common ADHD symptoms. It’s always better to understand the root cause of your conditions so you can treat ADHD first.

You Asked…

Can you develop ADHD in later life?

ADHD is a developmental disorder, not typically developed in later life. Symptoms present in childhood may go unrecognized until adulthood, giving the impression of late onset.

The 8 ADHD Symptoms You Should Know About

Interrupting Conversations Impulsively

One key element of both the Predominantly Hyperactive-Impulsive type of ADHD and the combined type is impulsivity. There are many ways this can show up in everyday life, but one of the most common is interrupting conversations.Finishing people’s sentences, butting in before you forget what you want to say, or adding unnecessary commentary are all forms of impulsively interrupting someone.Doing this repeatedly can often offend the person you’re speaking to, and signal that we don’t respect their thoughts or ideas - even if we do. This can easily lead to misunderstandings and relationship problems, as they just assume you’re either rude or have bad social skills.I know I’m guilty of doing this. But, it’s usually because I want to express my thoughts before I forget them, which I know I will. It’s either interrupt or admit ‘I forgot what I was going to say’ for the millionth time. It’s frustrating for us too. We’re usually taught how to identify social cues just like anyone else (although this can be a struggle for neurodiverse minds) and know that it’s perceived as rude immediately after blurting it out. But we can’t help it. The easiest way to avoid this becoming a problem is to tell the people you’re comfortable with beforehand. Pre-warning them that you might interrupt can prevent those awkward moments entirely. It’s also a good idea to apologize first, letting them know you appreciate what they’re saying.

Adult ADHD symptoms: Interupting people when they talk

Misplacing Items Due to Forgetfulness

Have you ever spent hours looking for something, only to find it somewhere completely bizarre? Yep, it happens a lot. And sometimes it’s completely in plain sight, not lost at all. I can’t count the number of times that my phone, which I’d spent 10 minutes turning the place upside-down looking for, turned out to be in my pocket or under where I was sitting.Many adults with ADHD are forgetful and inattentive. We’ll often be in our own worlds as we wander the house from room to room, not paying any attention. So when we put things down, we don’t even notice, let alone remember.And then there are the distractions. I’ll be looking for my ever-missing phone and notice that the plants need watering, the bin needs changing and I’ve got mail to sort. Well of course I need to sort all of these first. And order a new lightbulb. Oh! I need my phone. Where is it?Losing or misplacing things can be commonly experienced by someone with Attention Deficit Hyperactivity Disorder. ADHD individuals tend to lose their phones, keys, wallets, and other daily stuff potentially due to their dopamine levels and a problem with Object Permanence.According to the National Institute of Mental Health, Object Permanence is the cognitive ability to understand that objects continue to exist even when they can't be seen, heard, or felt. Adults with ADHD often struggle with object impermanence and may forget an object exists as soon as it isn’t in their line of sight. This is why many ADHD homes have open storage and clear containers, so their owners know what they own. Another way to manage this tendency to lose things is to make sure everything you own has a home, and you always make the effort to return it to its home..

Adult ADHD symptoms: Losing or misplacing things

Being Easily Distracted

Having ADHD often means you’re easily distracted and have difficulty paying attention.We’re drawn to anything that’s even slightly new or interesting. Many call this shiny object syndrome. This is because we have a heightened sensory system like each of our senses is dialed up to ten.This means we’re particularly sensitive to sounds, light, movement and even colors, and this can immediately pull our attention away from whatever we’re doing. This is often highly disruptive to our lives. Time-sensitive tasks become extra difficult because we never know when a distraction could set us behind schedule. Being distracted also leads to more careless mistakes.To manage this ADHD symptom, I pre-plan my days with to-do lists and timeblocking. For each task, I give myself more time than I think I’ll need to account for distractions.Digital distractions are a big one, so many people turn off notifications, use focus apps, or hide their phones away entirely until they’ve completed their tasks.

Adult ADHD symptoms: Being easily distracted


Anyone can be impatient and hate waiting around, but people with ADHD have a particularly low frustration tolerance for these things. Many of us with ADHD experience ‘waiting mode’. This is where, if you have a meeting or appointment later in the day, you feel stuck and can’t get anything done in the meantime. Personally, I get this when I’ve got a friend coming around. In the hours leading up to the time we agreed, I seriously struggled to do anything productive. And if they’re late, I get more annoyed than I should, with this sometimes turning into sadness or anger. If I get regular updates, it isn’t so bad, but if I have no idea what’s going on, I start to get anxious.The frustration of waiting can be compounded by other symptoms, such as trouble focusing, extreme restlessness, and inability to handle emotions. For a neurotypical person, it may seem easy to wait for an extra 15-30 minutes, but with many adults with ADHD, it can seem like forever. The best way I’ve found to manage this is to always have something to do that doesn’t require sustained mental effort. Podcasts and audiobooks are good options. I like to use waiting time to learn new things as it makes me feel productive in these otherwise ‘wasted’ moments.

Adult ADHD symptoms: Having difficulties to wait

Struggling with Impulsivity

"Oh! Look at that guitar, it’s beautiful AND it's on sale!" I didn’t know how to play the guitar or have any musical talent, but I’d suddenly fallen in love with the idea of being a musician. It was going to change my life. I quickly whipped out my credit card. Money wouldn’t be a problem when I was a legendary singer-songwriter. The joy I felt was immensely satisfying. But only for a couple of days. Inevitably, the guitar joined my long list of other hobbies I’d lost interest in and abandoned over the years.Impulsivity can be one of the most disruptive symptoms because it causes someone to speak or act immediately, without thinking of the consequences or planning ahead.In the moment, acting on impulsivity can feel really good. There’s the dopamine rush, which the ADHD brain craves, plus it often somehow feels like it relieves stress and anxiety. It also helps us avoid analysis paralysis, where making a decision can be overwhelming and paralyzing. But often, the consequences of these impulsive decisions outweigh the short-term relief we feel. In particular, a habit of impulse buying can result in financial issues, which has a knock-on effect on other areas of your life like your mental health.And then there’s riskier impulsive behaviors like substance abuse and binge drinking. There are ways to manage impulsivity. For example, with impulse buying, always wait at least 24 hours (ideally more) before checking out. You’ll usually find you no longer want it. For more serious forms of impulsivity like substance abuse, you should speak to a mental health professional about adult ADHD treatment. 

Adult ADHD symptoms: Struggling with impulsivity

Being Sensitive to Sensory Inputs

As we mentioned earlier, having a sensitive central nervous system can mean we experience heightened sensitivity to sensory stimuli like repetitive sounds, unpleasant smells, bright lights, or certain textures. When all these sensory inputs become too overwhelming to bear, it’s called sensory overload. Sensory overload forces the brain to respond as it would to a life-threatening situation, and enters fight, flight, or freeze mode.One of my biggest triggers happens when someone else is cooking. The clanging metal of pots and pans and the constant movement combined with whatever I’m trying to focus on is often overwhelming.While in a state of sensory overload, everything becomes too much. Background noise, light, touch - I personally can’t even bear to brush up against someone without it feeling like a shock: highly uncomfortable and upsetting. Knowing you’re susceptible to sensory stimuli is the first step forward because it means we can take steps to eliminate any potentially overwhelming stimuli. Here are a few ideas of how:

  • Always have noise-cancelling headphones or earplugs available. 
  • Use lamps or softer light bulbs instead of harsh overhead lighting.
  • Travel during less busy times (busy commuter trains have sent me into sensory overload a few times). 
  • Distance yourself from particularly strong smells, where possible.

When you’re in sensory overload, you want to reset your nervous system. My go-to solution is to lie down in a dark room for 10-15 minutes with headphones on, usually playing white noise, lo-fi, or my comfort songs.

Adult ADHD symptoms: Being sensitive to sensory inputs

Zoning Out During Conversations 

As someone with combined type ADHD - both hyperactive-impulsive and inattentive symptoms - long conversations can go two ways: either I interrupt them, or I zone out. It depends on how engaged and interested I am. If I’m not excited about a topic, my mind will take me someplace else. Maybe a beach, maybe inside my favorite TV show, who knows? And my excitement really is all or nothing, even regular - not boring - conversations can cause me to zone out.It’s not intentional. I don’t always know I’m doing it until later when I realize I don’t remember what was said. This symptom of inattention can put a strain on personal relationships. After all, you’re not paying attention to the other person, and often this is obvious. It’s understandable they could be offended. Practicing mindfulness can help you become more aware of your surroundings and ground yourself in the present in any situation, including conversations.

Adult ADHD symptoms: Zoning out during conversations

Struggling to Stay Organized

Difficulty staying organized is another big one, but unsurprising given other symptoms like forgetfulness and inattention. Organization is linked to executive functioning, which, as we mentioned earlier, many adults with ADHD have issues with.To stay on top of home organization and cleaning, I need a to-do list. Without one, nothing will get done. But even with one, my mind will wander and there’s a strong chance I’ll get distracted before I organize anything.Not only do we struggle with organizing our spaces, but our thoughts can get disorganized too. Internal hyperactivity can mean our thoughts are moving too quickly to be coherent and organized into well-structured thoughts. There are tons of organization tools and techniques. To-do lists and calendars are the essentials, but you may want something more complex to organize multiple areas of your life. We recommend you do research to find the one that works for you. And, a tip from someone who loves a good life management or productivity tool: it probably won’t work forever. You may quickly lose interest and seek the novelty of a new tool, so try not to invest too much time into one.

Adult ADHD symptoms: Struggling to stay organized

Visualize your ADHD traits!

Take our fun online quiz to visualize your ADHD traits and learn more about your brain!


You Asked…

What does ADHD in adults look like?

In adults, ADHD may manifest as difficulty focusing, impulsiveness, and disorganization, often leading to challenges in managing time, maintaining relationships, and achieving goals.

Navigating the Next Steps After Identifying ADHD Symptoms

Do you suspect you might have ADHD after recognizing the symptoms described? If so, it's crucial to consult a healthcare provider and seek evaluation from a mental health specialist. While the symptoms listed capture common experiences, ADHD's spectrum is broad, and other signs or co-occurring conditions might also play a role.

Once diagnosed, an ADHD specialist can guide you towards effective treatments, which may include medication, behavior therapy, or a combination tailored to your needs. Maintaining a healthy lifestyle - focusing on sleep, nutrition, exercise, and mindfulness - can also be a game-changer.

Want to understand more about how your symptoms show up in your life?

Our ADHD Self-Assessment Workbook by Alice is your perfect companion for exploring ADHD in the comfort of your home. Crafted by someone who's been through the late diagnosis journey, Alice designed this workbook to offer clarity, empathy, and understanding.

What You'll Find Inside

  • Detailed explanations and real-life examples for each ADHD symptom.
  • Self-assessment pages based on established criteria.
  • A comprehensive look at inattentive, hyperactive/impulsive, and unofficial ADHD symptoms.
  • Journaling sections with prompts for personal reflection.
  • Visual tools to map your unique ADHD profile.
  • Practical advice for pursuing a diagnosis and finding the right support.
  • Available for immediate digital download, you'll receive both a vibrant color version for digital devices and a printer-friendly black and white edition.

Grab your copy here for just $21, and start your journey towards finally understanding yourself.

Key Takeaways

  • ADHD symptoms vary among adults due to differences in brain functioning and how they’ve evolved from childhood over time.

  • Attention deficit hyperactivity disorder is diagnosed using the DSM-5 criteria, but comorbidities (such as a mood disorder) and overlapping symptoms can complicate the diagnosis process, leading to misdiagnosis and ineffective treatment.

  • Common symptoms of ADHD include:

    • Zoning out during conversations
    • Struggling to stay organized
    • Impatience and struggling to wait
    • Impulsivity
    • Being easily distracted
    • Interrupting conversations
    • Misplacing objects and forgetfulness
    • Sensory overload

Understanding and managing adult ADHD symptoms is crucial for improving daily functioning and overall well-being. 

By seeking proper diagnosis and adopting effective coping strategies, individuals can navigate their challenges more successfully. Remember, you're not alone in this journey, and with the right support and techniques, you can thrive despite ADHD's unique hurdles.

What’s Next?

To explore a potential adult ADHD diagnosis further, we recommend giving these articles a read next.

Signs of ADHD: Understanding Beyond the Official Criteria

8 ADHD Sypmtoms
Start your ADHD diagnosis journey!

Visualize and assess 25 ADHD traits and understand how they affect your life.

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Frequently Asked Questions (FAQs)

I have other friends with ADHD that don't exhibit these ADHD symptoms. Why is that?

ADHD symptoms can vary from person to person. Also, there are three types of ADHD: Predominantly Hyperactive-Impulsive, Predominantly Inattentive, and Combined ADHD Type. These categories have different symptoms for ADHD adults.

Can other mental health conditions affect the symptoms of ADHD?

Yes, they can. Comorbidities are other mental health conditions that can co-occur with ADHD. For example, ADHD and Anxiety Disorders can happen together and have overlapping symptoms, affecting your symptoms and diagnosis. Misdiagnosis can sometimes happen if these traits are overlooked.

How do you treat ADHD, and is it necessary to have ADHD medications?

There are different approaches to managing the different ADHD traits and symptoms. It can start with a healthy lifestyle and some self-care techniques to help you focus and calm yourself. If necessary, medications for ADHD can be taken under strict guidance from your physician. There are also different types of therapy, like Cognitive Behavioral Therapy, that can help you understand and change the way you think and act.

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