Why is diagnosis delayed in ADHD + bipolar individuals? 

Delayed diagnosis in people with both ADHD and bipolar disorder is common and often deeply frustrating. According to NHS England’s Independent ADHD Taskforce Report (2025), overlapping symptoms such as impulsivity, distractibility, and mood swings frequently blur the line between the two conditions. Because these symptoms can appear similar, clinicians may initially treat mood instability while missing long-standing ADHD features. This overlap can lead to years of uncertainty before a full, accurate diagnosis is reached. 

Why diagnostic delays happen 

Identifying ADHD in people who also have bipolar disorder requires careful assessment of symptoms, timing, and persistence. Many of the core features overlap, which makes it challenging for both patients and clinicians. As explained by the Royal College of Psychiatrists, ADHD symptoms are chronic and present since childhood, while bipolar symptoms occur in episodes of mania or depression that begin later in life. During active mood episodes, mood-driven behaviours may hide or mimic ADHD, delaying recognition. 

Symptom overlap and clinical confusion 

A 2025 PubMed review found that between 15 and 20 per cent of people with bipolar disorder also meet the criteria for ADHD. When both conditions occur together, ADHD may only become apparent once mood symptoms stabilise. NICE advises deferring an ADHD diagnosis until mood is stable to avoid confusing temporary mood-related changes with chronic attention difficulties, as outlined in NICE NG87 and NG136. 

System barriers and patient experience 

Delays are not only clinical but also systemic. Long NHS waiting lists, limited access to multidisciplinary assessments, and inconsistent regional pathways all contribute to late diagnosis. Reports such as Healthwatch UK’s 2025 ADHD report note that women and minoritised groups are particularly affected by under-recognition and slower referrals. These delays can cause distress, poor treatment experiences, and increased risk of relapse or self-harm, as reported by RCPsych. 

Key takeaway 

Diagnosis is often delayed in ADHD and bipolar individuals because symptoms overlap, fluctuate, and are influenced by system barriers. According to NICE and NHS guidance, accurate diagnosis relies on timing, chronicity, and multidisciplinary assessment once mood is stable. Recognising these complexities helps ensure earlier support, appropriate treatment, and better long-term outcomes. 

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.