How do overlapping symptoms cause misdiagnosis? 

When symptoms of ADHD, autism, anxiety, and depression overlap, it often becomes challenging for healthcare professionals to make an accurate diagnosis. Many people experience shared traits such as inattentiveness, restlessness, emotional dysregulation, and low mood, which can appear similar across several conditions. According to NICE guidance on ADHD (NG87), these overlapping features mean that diagnosis should always involve a detailed developmental history, structured assessments, and information from multiple sources such as family or teachers. 

Why overlapping symptoms make diagnosis difficult 

Autism guidance from NICE (CG142) and the NHS England Autism Framework (2023) explain that characteristics such as social communication differences and repetitive behaviours can resemble ADHD-related attention issues or anxiety-linked withdrawal. This overlap can lead to children or adults being misdiagnosed with depression or anxiety when their primary difficulties are neurodevelopmental. 

NICE and NHS guidance 

NICE recommends that ADHD should be diagnosed by specialists who apply DSM-5 or ICD-10 criteria and carefully distinguish between neurodevelopmental and mental health disorders. The NHS ADHD Taskforce (2025) notes that “diagnostic overshadowing” often occurs when anxiety or depression masks ADHD or autism traits. Clinicians are advised to assess the persistence and context of symptoms across home, school, and social environments rather than relying on single clinical observations. 

Expert and research perspectives 

The Royal College of Psychiatrists’ 2023 guidance highlights how masking and gender bias contribute to diagnostic delays, particularly among women and girls. A 2022 review published in PubMed (Frazier et al.) found that emotional instability, impulsivity, and concentration difficulties frequently overlap, leading to confusion between ADHD, autism, and mood disorders. 

Key takeaway 

Overlapping symptoms across ADHD, autism, anxiety, and depression can blur diagnostic boundaries. However, careful, multidisciplinary, and longitudinal assessment enables clinicians to distinguish between conditions more accurately. Greater awareness of masking, gender bias, and developmental context is essential to improve diagnostic accuracy and ensure timely access to appropriate support. 

Harriet Winslow, BSc

Author

Harriet Winslow is a clinical psychologist with a Bachelor’s in Clinical Psychology and extensive experience in behaviour therapy and developmental disorders. She has worked with children and adolescents with ADHD, autism spectrum disorder (ASD), learning disabilities, and behavioural challenges, providing individual and group therapy using evidence-based approaches such as CBT and DBT. Dr. Winslow has developed and implemented personalised treatment plans, conducted formal and informal assessments, and delivered crisis intervention for clients in need of urgent mental health care. Her expertise spans assessment, treatment planning, and behavioural intervention for both neurodevelopmental and mental health conditions.

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

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.