It is a neurodevelopmental disorder, meaning impairing symptoms must have been present in childhood, except for when ADHD occurs after traumatic brain injury.
[12] Diagnosis is made clinically, via a comprehensive, structured interview with the purpose of obtaining a full history of the individual's current and childhood symptoms and their negative impact on daily functioning.
[6][13][14] Supplemental history obtained from people close to the individual in different settings (e.g., parents, siblings, partners, teachers, coworkers, and employers) can help confirm a diagnosis.
[17][18] Individuals with ADHD exhibit deficiencies in self-regulation and self-motivation, which in turn foster problematic characteristics such as distractibility, procrastination, and disorganization.
These result in problems with sustaining attention, planning, organization, prioritization, time management, impulse control, and decision making.
[7] The difficulties generated by these deficiencies can range from moderate to extreme, resulting in the inability to effectively structure their lives, plan daily tasks, or think of and act accordingly even when aware of potential consequences.
[23] Studies on adults with ADHD have shown that, more often than not, they experience self-stigma and depression in childhood, commonly resulting from feeling neglected and different from their peers.
Unlike other symptoms of ADHD that tend to improve or decline with age, emotional dysregulation has been shown to be more persistent into adulthood.
[10][12][13] The Adult ADHD Self Report Rating Scale (ASRS) is a validated screening tool recognized by the World Health Organization (WHO) with a sensitivity and specificity of 91.4% and 96.0%, respectively.
[13] Screening can guide clinical decision-making toward the proper diagnostic and treatment methods, can prevent further negative outcomes, and can reduce medical costs that may result from underdiagnosis.
[10][13] Individuals who should be screened for ADHD include any adult with a chronic history of behaviors consistent with inattention, hyperactivity, impulsivity, restlessness, and emotional instability that started in childhood or early adolescence.
As a result, when they seek treatment as adults, they may not demonstrate the level of dysfunction that is more readily recognized in individuals with ADHD.
[7] Other results of adult ADHD are higher reported incidences of traffic citations, missed workdays, and accidents.
[33] According to Fritz in a 2016 study, adult men with ADHD may be able to focus better on mental tasks after completing some type of physical exertion.
[15][7] In females with ADHD, inattention often manifests as susceptibility to distraction, disorganization, feeling overwhelmed, forgetfulness, absence of effort or motivation, and difficulty receiving constructive criticism in professional settings.
[15] Notable symptoms of ADHD specific to adult females include lower self-esteem which can lead to self-harm, greater difficulty in maintaining relationships, increased risk of anxiety and/or mood disorders.
[9][15] Females, beginning in childhood, are also more likely to develop compensatory strategies that may ultimately mask some of the primary symptoms of ADHD, because of societal gender roles that pressure young women/girls to take up less space and not be disruptive.
Consequently, females demonstrate a higher frequency of a "life-persistent" form of ADHD, which helps explain the narrowing male-to-female diagnostic ratio from childhood to adulthood.
[15] Another possible explanation for the male-to-female diagnostic ratio seen in adulthood is that adult diagnosis relies more heavily on self-report than reports from parents or teachers.
[36] Several lines of research based on structural and/or functional imaging techniques, stimulant drugs, and psychological interventions have identified alterations in the dopaminergic and adrenergic pathways of individuals with ADHD.
The uptake transporters for dopamine[37] and norepinephrine[38] are overly active and clear these neurotransmitters from the synapse a lot faster than in other individuals.
[41] This is vital to ensure that adults with ADHD can make informed decisions about their treatment and have other benefits, such as improved relationships with others.
[41] A 2025 meta-analytic systematic review of 113 randomized controlled trials demonstrated that stimulant medications significantly improved core ADHD symptoms in adults over a three-month period, with good acceptability compared to other pharmacological and non-pharmacological treatments.
[49] For people who cannot be treated with stimulants due to a substance use disorder or other contraindications, atomoxetine is the suggested first-line treatment in the UK.
It is particularly effective for those with the predominantly inattentive concentration type of attention deficit due to being primarily a norepinephrine reuptake inhibitor.
A rare but potentially severe side effect includes liver damage and increased suicidal ideation.
[41] Viloxazine, another selective norepinephrine reuptake inhibitor, was FDA-approved to treat ADHD in children, adolescents, and adults.
[54] Psychotherapy, including behavioral therapy, can help an adult with ADHD monitor their own behaviour and provide skills for improving organization and efficiency in daily tasks.
[27][55] Research has shown that, alongside medication, psychological interventions in adults can be effective in reducing symptomatic deficiencies.
[34] The expansion of the definition for ADHD beyond only being a condition experienced by children was mainly accomplished by refocusing the diagnosis on inattention instead of hyperactivity.