ADHD risk factors: what may raise the chance of ADHD

What ADHD is

ADHD is a developmental disorder marked by persistent symptoms of inattention, hyperactivity and impulsivity. Some people mostly have inattention, others mostly hyperactivity and impulsivity, and some have both. Symptoms begin in childhood and can interfere with relationships and with school or work. ADHD is well known in children and teens, but many adults also have it, and effective treatments are available (NIMH). It is one of the most common disorders diagnosed in children (NIMH).

It is common to show these behaviors some of the time. For people with ADHD, the behaviors are frequent, happen across several settings such as school, home and work, and interfere with daily life (NIMH). There is no score or calculator on this page; the factors below are the ones NIMH and MedlinePlus name.

What may raise the chance of ADHD

Researchers are not sure what causes ADHD. It probably results from a combination of factors (NIMH) (MedlinePlus):

• Genes. Many studies suggest that genes play a large role (NIMH).
• Brain development. Researchers are looking at differences in brain development and neurobiology between people with and without ADHD (NIMH).
• Environmental factors under study. Factors that might increase the risk include brain injuries, nutrition and social environments (NIMH) (MedlinePlus). NIMH-supported research is also looking at hormones and other molecules, and at exposures before birth and early in life (NIMH).

NIMH says researchers are still studying these environmental factors (NIMH).

How ADHD shows at different ages and in different people

Anyone can have ADHD. Boys and men tend to show more hyperactive and impulsive symptoms, while girls and women are more likely to be diagnosed with inattentive ADHD (NIMH). In children, hyperactivity and impulsivity are the most common symptoms; as school and social demands grow, inattention often becomes more noticeable. Teens usually show less hyperactivity and may seem restless or fidgety. Adults can show inattention, restlessness and impulsivity, and may be irritable or have frequent mood changes (NIMH).

Some adults were not diagnosed when younger because the disorder was not recognized, it was mild, or they managed well until the demands of adulthood. It is never too late to seek a diagnosis and treatment (NIMH) (MedlinePlus).

Signs and symptoms

• Inattention: careless mistakes, trouble concentrating or listening when spoken to directly, trouble following instructions or finishing tasks, trouble organizing tasks and managing time, losing things such as keys, wallets and phones, being easily distracted, and forgetting daily activities (NIMH) (MedlinePlus).
• Hyperactivity and impulsivity: fidgeting or squirming, getting up when expected to stay seated, running or climbing when it is not appropriate (or feeling restless, in teens and adults), being constantly "on the go", talking excessively, answering before questions are finished, trouble waiting, and interrupting others (NIMH) (MedlinePlus).

How ADHD is diagnosed

Symptoms must begin in childhood, before age 12. Children up to 16 must show at least six symptoms of inattention, hyperactivity and impulsivity, or both; people over 16 must show at least five. The symptoms must last at least 6 months, appear in two or more settings, and interfere with social, school or work functioning (NIMH). Stress, sleep disorders, anxiety, depression and other conditions can cause similar symptoms, so a health care provider needs to do a thorough evaluation (NIMH). There is no single test to diagnose ADHD (MedlinePlus).

ADHD often occurs with other conditions, such as disruptive behavior, learning disorders, sleep problems, anxiety or depression (NIMH). See anxiety risk factors and depression risk factors.

In adults, some autism symptoms can overlap with ADHD, which can make autism harder to diagnose (NIMH). See autism risk factors.

Treatment and getting help

There is no cure, but treatment can reduce symptoms and improve functioning. Common treatments are medication, psychotherapy and other behavioral interventions; for children, treatment often includes parent education and school-based programs (NIMH). Stimulants are the most common medicines for ADHD and must be prescribed and monitored by a health care provider (NIMH). If you are unsure where to get help, a health care provider is a good place to start and can refer you to a mental health professional such as a psychologist, psychiatrist or clinical social worker (NIMH).

The 988 Lifeline is free and confidential and available 24/7 (988 Lifeline).

Common questions

Is ADHD genetic?

Many studies suggest genes play a large role, but ADHD probably results from a combination of factors (NIMH).

Can adults have ADHD?

Yes. Many adults have ADHD, and some are not diagnosed until adulthood, although symptoms must have begun before age 12 (NIMH) (MedlinePlus).

Is ADHD different in girls?

Girls and women are more likely to be diagnosed with inattentive ADHD, while boys and men tend to show more hyperactive and impulsive symptoms (NIMH).