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What Are the Top 3 Signs of ADHD? 

PostedOctober 13, 2025
UpdatedOctober 13, 2025
ByMy Patient Advice
Author: Avery Lombardi, MSc | Reviewed by: Dr. Rebecca Fernandez, MBBS

ADHD is characterised by a variety of symptoms, but the top 3 signs of ADHD are generally inattention, hyperactivity, and impulsivity. These core symptoms can impact daily functioning, relationships, and academic or professional performance. Recognising these top 3 signs of ADHD is crucial for early intervention and proper diagnosis. 

Take an ADHD test

Inattention 

Inattention is one of the most prominent signs of ADHD. Individuals with ADHD often struggle to stay focused on tasks, particularly those that are repetitive or boring. They may frequently lose focus during conversations, forget instructions, or misplace things like keys or assignments. This can lead to difficulties in school, work, or managing daily tasks. 

Hyperactivity 

Hyperactivity refers to excessive physical movement, fidgeting, or restlessness. While this symptom is more obvious in children, adults with ADHD can also experience internal restlessness, which might not be as visible. In children, it often shows up as difficulty sitting still, running around, or being overly active in situations where stillness is required, such as in a classroom setting. 

Impulsivity 

Impulsivity is another key symptom. This involves making decisions without considering the consequences. It can manifest as interrupting others during conversations, difficulty waiting for turns, or engaging in risky behaviours without thinking them through. Impulsivity can disrupt social interactions and lead to challenges in work and academic settings. 

In conclusion, recognising these key symptoms and understanding the diagnostic criteria is the first step toward seeking an accurate diagnosis and effective treatment plan. ADHD symptoms can vary widely in severity, so it’s essential to seek professional help if these signs are affecting daily life. 

Visit providers like ADHD Certify for personal consultations and expert guidance tailored to your unique situation. 

For a deeper dive into the science, diagnosis, and full treatment landscape, read our complete guide to Signs, Symptoms, and Self-identification of ADHD.  

Take an ADHD test
Avery Lombardi, MSc, author for my patient advice - mypatientadvice.co.uk
Avery Lombardi, MSc
Author

Avery Lombardi is a clinical psychologist with a Master’s in Clinical Psychology and a Bachelor’s in Psychology. She has professional experience in psychological assessment, evidence-based therapy, and research, working with both child and adult populations. Avery has provided clinical services in hospital, educational, and community settings, delivering interventions such as CBT, DBT, and tailored treatment plans for conditions including anxiety, depression, and developmental disorders. She has also contributed to research on self-stigma, self-esteem, and medication adherence in psychotic patients, and has created educational content on ADHD, treatment options, and daily coping strategies.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy. 

Dr. Rebecca Fernandez, MBBS, author and a reviewer for my patient advice - mypatientadvice.co.uk
Dr. Rebecca Fernandez, MBBS
Reviewer

Dr. Rebecca Fernandez is a UK-trained physician with an MBBS and experience in general surgery, cardiology, internal medicine, gynecology, intensive care, and emergency medicine. She has managed critically ill patients, stabilised acute trauma cases, and provided comprehensive inpatient and outpatient care. In psychiatry, Dr. Fernandez has worked with psychotic, mood, anxiety, and substance use disorders, applying evidence-based approaches such as CBT, ACT, and mindfulness-based therapies. Her skills span patient assessment, treatment planning, and the integration of digital health solutions to support mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewer's privacy.