Attention Deficit Hyperactivity Disorder (ADHD) Overview

ADHD is a neurodevelopmental disorder that is characterized by inattention, hyperactivity, and/or impulsivity.^{1 , 2} Although ADHD can be diagnosed at any age, ADHD symptoms typically emerge in early childhood and can cause significant disruption in everyday life, impacting relationships, sleep, and school or work performance.³ Children with ADHD are at increased risk for injuries, while adults and teens with ADHD are more likely to engage in risky behaviors, such as substance use.³ Most individuals with ADHD have one or more co-occurring conditions, with more than two-thirds affected by disorders such as sleep disorders; anxiety, depression, and other mood disorders; learning disorders; or substance use disorders.^{3 , 4}

ADHD's exact cause is unknown; it is likely a result of a combination of factors.¹ ADHD commonly involves gene variants, each with small effects, that interact with environmental factors to influence individual risk.⁴ Less commonly, it results from rare gene variants or chromosomal abnormalities that can directly cause ADHD as part of a broader genetic syndrome.⁴ ADHD tends to run in families, suggesting a strong genetic component.⁴ Other possible risk factors include environmental factors, such as prenatal exposures and complications, heavy metal exposure, and child health conditions (e.g., brain injuries).^{1 , 2 , 4 , 5}

ADHD is diagnosed at a lower rate in girls than in boys, with studies indicating that boys are two to three times more likely to receive a diagnosis than girls; by adulthood, however, women and men receive diagnoses at roughly the same rate.^{2 , 6} ADHD is often underdiagnosed in girls and teens early in life, which is largely attributed to less overt symptom manifestation.^{6 , 7} They typically exhibit a predominance of inattention symptoms (meaning difficulty remaining focused, distractibility, or disorganization) accompanied by internalizing features, whereas boys and men are more likely to present with pronounced hyperactive-impulsive behaviors that are externally observable.⁶ ADHD in girls and women carries unique risks, including social difficulties, such as bullying; relationship problems, including partner violence; and higher rates of teenage pregnancy, eating disorders, nonsuicidal self-injury, suicidal ideation, and suicide attempts.⁸ Limited evidence suggests ADHD symptoms in females may fluctuate with hormonal life stages, often worsening during periods of hormonal change, such as puberty, across the menstrual cycle, and possibly during perimenopause.⁹ These shifts may be related to shifts in estrogen levels.⁹ Higher-estrogen states may be associated with symptom stability or improvement.⁹

Diagnosing ADHD is a multi-step process. Thorough assessment involves a series of ruling out other conditions (e.g., anxiety, depression, thyroid disease, sleep problems), reviewing medical and family history, and using questionnaires and/or interview questions to assess symptoms and functioning.^{1 , 2} Compensatory behaviors in females, such as socially adaptive behaviors or increased resilience that mask or downplay symptoms in certain settings, can make diagnosis more difficult.^{8 , 10} Treatment for ADHD is highly individualized and may include a combination of medication, behavioral treatments (e.g., cognitive behavioral therapy), and education and training to help individuals and families develop skills and strategies for managing their condition.^{1 , 2} Two types of medications, stimulants and nonstimulants, are approved by the Food and Drug Administration to help reduce ADHD symptoms and improve functioning.¹⁰

The primary NIH organization for research on ADHD is the National Institute of Mental Health (NIMH). NIMH supports research to better understand the causes of ADHD; improve diagnosis across the lifespan; and evaluate the effectiveness of treatments, services, and interventions for people with ADHD and their families.

A 2020 consensus review that was supported by NIMH found that ADHD in females is frequently underrecognized and often presents with more inattentive symptoms and internalizing comorbidities, contributing to delayed diagnosis and unique functional impairments across the lifespan.¹⁰ These findings highlight the need for improved, sex-informed diagnostic approaches and tailored clinical strategies to better identify and treat ADHD in girls and women.

Current NIMH research is exploring a range of approaches to improve ADHD treatment and understanding in children and adults, including how new technologies, such as virtual reality and mobile apps, can aid in behavior-change therapies. Researchers are examining the effectiveness of potential newer treatment approaches—such as cognitive training, mindfulness, and neuromodulation—both independently and in combination with standard ADHD treatments. NIMH is also conducting symptom-based studies in children, adolescents, and young adults to investigate the neural and genetic underpinnings of impulsivity and compulsivity—traits that commonly overlap with ADHD—to inform future diagnostic and treatment approaches.¹¹