How do genetic risks overlap ADHD and bipolar? 

Both ADHD and bipolar disorder have strong genetic components, and research over the past decade has shown significant overlap between the two. According to the Royal College of Psychiatrists, both conditions tend to run in families, with heritability estimates of around 70 to 90 per cent for bipolar disorder and 70 to 80 per cent for ADHD. This means that close relatives of someone with either condition is more likely to experience similar mental health traits, though not necessarily the same diagnosis. These shared patterns suggest that overlapping genetic pathways influences how mood, motivation, and attention are regulated in the brain. 

Understanding shared genetic and biological factors 

Recent genome-wide association studies (GWAS) have provided strong evidence of genetic overlap. A large PubMed meta-analysis (2024) found a genetic correlation of roughly 0.65 between ADHD and early-onset bipolar disorder, highlighting shared genome-wide risk variants. These studies show that both conditions involve similar neurobiological mechanisms, particularly within dopamine and serotonin systems that influence mood and focus. Research from NICE and NHS guidance confirms that genetic and biological factors play a role in vulnerability to both conditions, even though they are not sufficient alone to determine who develops either disorder. 

Key shared genetic markers and pathways 

Genes affecting dopamine and serotonin transmission, including DRD4, DAT1, and SLC6A4, are linked to both ADHD and bipolar disorder. These genes influence impulsivity, attention, and mood regulation. Additionally, circadian rhythm genes, which control sleep and energy cycles, have been associated with both disorders. Evidence from Nature (2024) and PubMed suggests that disruptions in sleep-wake regulation and neurotransmitter balance may explain why many individuals experience overlapping symptoms such as mood swings, energy shifts, and concentration difficulties. 

Impact on diagnosis and treatment 

Recognising shared genetic risks helps clinicians understand why ADHD and bipolar disorder often appear together. A JAMA Psychiatry study found that individuals with higher genetic loading tend to experience earlier symptoms of onset and greater severity. However, as NICE guidance notes, genetic testing is not currently used for diagnosis because risk genes are common in the general population. Instead, awareness of shared biology supports more accurate assessment, early intervention, and informed discussions within families about mental health risk. 

Key takeaway 

ADHD and bipolar disorder share several genetic and biological risk factors involving dopamine, serotonin, and circadian systems. While these findings do not yet change clinical practice, they highlight why the two conditions often coexist and why early, detailed assessment remains essential. Understanding the shared roots of both conditions can improve awareness, reduce stigma, and encourage proactive support for individuals and families. 

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.