The Different Types of ADHD
Attention Deficit Hyperactivity Disorder is a neurodevelopmental disorder characterised by patterns of inattention, hyperactivity and impulsivity. Individuals with ADHD experience different symptoms, which often change over time and during different life stages like puberty, adulthood and the menopause.
ADHD can also be subcategorised into three main categories:
1. Predominantly Inattentive Type (ADHD-PI)
The inattentive subtype of ADHD accounts for 20–30% of cases. People with inattentive type ADHD can have difficulty keeping their concentration, get easily distracted, or forget things. This means they may struggle with following instructions, organisation, time tracking and management, finishing tasks, and attention to detail.
2. Predominantly Hyperactive-Impulsive Type (ADHD-PHI)
Despite negative stereotypes presenting ADHD as a disorder of hyperactivity and impulsiveness, the hyperactive-impulsive ADHD subtype accounts for only around 15% of cases. However, the physical symptoms of this type of ADHD (excessive movement and/or talking, restlessness, fidgeting and restlessness) can make it easier to recognise. What’s less easy to spot (and often more debilitating) is individuals’ non-physical hyperactivity: racing thoughts, ruminations, and a constant struggle to relax and slow down.
3. Combined Type (ADHD-C)
As probably expected, the combined type ADHD includes both inattentive and hyperactive-impulsive symptoms, depending on the individual. This is the most common type of ADHD – accounting for around 50–75% of all cases.
Conditions that coexist with ADHD
ADHD can co-exist with other neurodevelopmental conditions and disorders, like dyslexia, dyspraxia, dyscalculia and dysgraphia, as well as some mood and anxiety disorders. These comorbidities can affect individuals’ experiences of ADHD.
There is also a significant overlap between ADHD and autism:
-
1
Around 50–70% of individuals with autism also present with ADHD. -
2
A recent poll of adults in England with suspected or diagnosed ADHD also revealed that 45% of them reported to have autism as well.
Changes in ADHD over time
One thing that I have noticed on my own journey, which research backs up, is that ADHD can change over time.
In the past, it was believed that children normally grew out of ADHD in adulthood. It’s now thought that these estimates are flawed because they didn’t take a lifelong trajectory of ADHD into account.
After looking into ADHD over the long term, studies suggest that symptoms and impairments change more over time than initially thought. I am showing more traits of autism than I did a few years ago, but I think that could be because my medication is suppressing a lot of my ADHD traits.
The reasons for ADHD symptoms changing over time are complex and individual, but it can be due to a combination of environmental and lifestyle factors. If you have inattentive or combined type ADHD and struggle with memory or organisation, the already heavy mental load of adult responsibilities is probably going to make that worse. If you are hyperactive-impulsive type ADHD but you’re working in an environment where you feel you have to mask symptoms, they may not be obvious to outsiders.
ADHD is not a monolith
With different subtypes and presentations of ADHD, changes in symptom expression across the lifespan, and the frequent presence of comorbid conditions such as anxiety, depression, or learning differences, each individual’s experience of ADHD can look quite distinct and may shift over time. As a result, ADHD cannot be understood or managed as a single, uniform condition.
Instead, it is a dynamic and highly individualised neurodevelopmental profile, where symptoms, challenges, and strengths can evolve in response to developmental stage, environment, and life demands. This variability means that treatment approaches and coping strategies should not be static; they need to be regularly reviewed and adapted so they remain effective and responsive to a person’s current needs, circumstances, and goals.
1. https://pmc.ncbi.nlm.nih.gov/articles/PMC8918663/
2. https://www.healthwatch.co.uk/blog/2025-07-28/impact-having-adhd-and-autism
https://cks.nice.org.uk/topics/attention-deficit-hyperactivity-disorder/background-information/prevalence/
About the Author
Ruth Bartlett is a Neuroinclusive Communications Specialist and founder of Wordsted. She combines her background in communication and community support with her neurodivergent lived experience to help organisations and teams bridge the gap between systems, processes, and their neurodivergent consumers and employees.
