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Understanding ADHD symptoms

Understand ADHD core symptoms like inattention, impulsivity, and hyperactivity. Learn how they differ by age and gender, and what conditions ADHD can co-occur with.

Three young women lying on a picnic blanket in a park, smiling and reading a magazine together, with flowers around them on a sunny day.
Dr Daniel
Medically reviewed by Danielle Mulligan ADHD Clinician

Reading time: 3 min

Uploaded on: January 27, 2026

ADHD is a neurodevelopmental condition, meaning that it impacts how your brain works, affecting things like behaviour, focus, and how you respond to the world around you.

If you think you or someone close to you may have ADHD, you might have lots of questions about it and its symptoms.

So, in this post, we’ll take a look at:

  • What the symptoms look like in
    • children,
    • teenagers, and
    • adults
  • What are some differences between genders
  • And what other conditions can cause similar symptoms or happen at the same time as ADHD

What are the core symptoms of ADHD?

ADHD doesn’t look the same for everyone, and its symptoms can vary from person to person.

It can show up as:

  • Mostly inattentive ADHD type, when staying focused and organised is the main struggle
  • Mostly hyperactive-impulsive ADHD type, when restlessness and acting on impulse are more noticeable
  • Mixed ADHD type, which presents as a mix of both inattentive and hyperactive-impulsive symptoms

Inattention Inattention symptoms of ADHD: Difficulty sustaining attention in tasks or play. Trouble following instructions and completing tasks. Getting easily distracted by external stimuli. Frequently losing or misplacing necessary items. Difficulty organising tasks and activities. Challenges with finishing tasks on time. Avoiding or disliking tasks that require sustained mental effort. Forgetfulness in daily activities. Making careless mistakes. Appearing not to listen when spoken to directly. Hyperactivity Hyperactive symptoms of ADHD: Fidgeting or squirming in seats. Leaving your seat in situations where remaining seated is expected. Running about or climbing in inappropriate situations (in adults, may be restlessness). Difficulty playing or engaging in leisure activities quietly. Being "on the go," acting as if "driven by a motor." Excessive talking. Interrupting conversations. Impulsivity Impulsive symptoms of ADHD: Blurting out answers before questions have been completed. Difficulty waiting for your turn. Interrupting or intruding on others. Acting without thinking of consequences. Difficulty controlling emotions.

ADHD is usually diagnosed when these symptoms start to seriously impact your everyday life, whether that’s at school, work, or in social situations.

Jump to ADHD Symptoms by Age and Gender.

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Reading time: 3 min

Uploaded on: January 27, 2026

Dr Daniel
Medically reviewed by Danielle Mulligan ADHD Clinician Registered with GMC (15A0206E) January 27, 2026 Meet Danielle Mulligan
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Written by Focused Content Team
Last updated on January 27, 2026
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