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Types of ADHD and How They Manifest in Adults

The definitions of hyperactive and inattentive ADHD were built with children in mind. Understanding how they translate into adulthood can help identify ADHD among adults and take the necessary steps to start addressing ADHD symptoms.

November 2022, Agave Health Team

The majority of people have heard and read about the main types of ADHD: hyperactive, inattentive, and combined. In the context of adult ADHD, these definitions may initially seem arbitrary. After all, like most things about ADHD, they were defined with children in mind.

ADHD indeed presents itself differently in children and adults - a fact confirmed by the Centers for Disease Control and Prevention (CDC). And it is precisely due to these differences that most adults with ADHD move through life undiagnosed and untreated.

Understanding those patterns and signs is empowering, as it helps one take charge of their life and address difficulties they’ve likely faced since childhood.


In adults, inattention tends to be a more prevalent concern than hyperactivity.

“Some people think of ADHD as mostly the hyperactive boy type, but many people with ADHD struggle mostly with inattentive symptoms, such as distractibility, forgetfulness, disorganization, procrastination, and poor time management,” states Mark Bertin, MD, a developmental pediatrician, in Psychology Today.

Inattention can manifest itself through a range of symptoms, including:

  • Distractfulness

  • Forgetfulness

  • Struggles with time management and planning

  • Difficulty prioritizing

  • Trouble multitasking

  • Procrastination

As a result of these symptoms, adults with ADHD tend to have more marital disagreements, difficulties building their career, get into accidents, and more. Such occurrences can lead to much bigger consequences. For instance, forgetting to book or missing health appointments can further deteriorate one’s health. Procrastination or inconsistency may get in one’s way of maintaining a healthy lifestyle: keep up with a healthy diet, get enough sleep and exercise.

In addition to the direct impacts of inattentive ADHD on physical health and overall wellbeing, absence of diagnosis can also lead to low self-esteem, anxiety, and depression because people can misinterpret their struggles as personal failures.


When hyperactivity persists into adulthood, it manifests itself through rushed thinking, restlessness, and impulsivity.

Adults with hyperactive ADHD are often described as spontaneous, overly chatty, and hot-tempered. They struggle to reign in their thoughts and emotions - positive or negative - which can impact relationships with loved ones, friends, and colleagues.

Restlessness can be equally pernicious; it can even limit one’s career. For example, many adults with ADHD find sitting in front of the computer all day unbearable. Conversely, choosing a career path that works with rather than against one’s symptoms can be liberating.

When are inattention and hyperactivity signs of ADHD?

Everyone feels overwhelmed, emotional, and disorganized at times. However, this doesn’t mean that everyone has ADHD. Those with ADHD experience a pervasive and continuous pattern of inattention or hyperactivity (or both). For this reason, one receives a formal diagnosis of ADHD only when they experience symptoms for at least six months and only when they recall signs of ADHD before age 12.

Current research maintains that ADHD is a neurodevelopmental disorder that usually appears in childhood and persists until adulthood. And the persistence is very common: a large-scale study published in the American Journal of Psychiatry in 2021 suggests that 50% of all children diagnosed with ADHD experience symptoms in adulthood.

Note that these symptoms can sometimes come and go. Rather than always being forgetful, adults with ADHD can do well for some time but suddenly be overwhelmed again —this process, known as overcompensation, is widespread among adults with ADHD.

One aspect that helps confirm ADHD in adults is that usually, symptoms spread to several life contexts: work, home, and sometimes even online. The presentation of symptoms in various settings is a criterion of ADHD, as per the DSM-5*.

Knowing how the different types of ADHD manifest themselves in adulthood versus childhood can bring great relief to ensure one isn’t wrong in believing they might have ADHD. Moreover, whether formally diagnosed or not, one can always build skills that help navigate those symptoms even without seeking medication. Cognitive behavioral therapy and coaching are known to be particularly effective in building those skills and carry no risk.

*The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (5th edition)

References: American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, 5th edition. Arlington, VA., American Psychiatric Association, 2013.

Sibley MH, Arnold LE, Swanson JM, et al. Variable patterns of remission from ADHD in the multimodal treatment study of ADHD. Am J Psychiatry. 2021.


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