Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition that causes people to become impulsive and hyperactive and pay less attention to everyday activities.

Healthcare professionals typically diagnose ADHD during childhood, but the condition can persist into adulthood.

According to the Anxiety and Depression Association of America (ADAA), 60% of children with ADHD in the United States grow into adults with ADHD.

They also note that under 20% of adults with ADHD receive a diagnosis or treatment, and that around a quarter of these adults seek medical help.

This article will discuss what adult ADHD is, its causes and symptoms, how doctors diagnose and treat it, and whether or not any other conditions may coexist with ADHD.

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Even though doctors tend to diagnose ADHD in childhood, the condition can also affect adults.

ADHD, which some people may also know as ADD, is a neurodevelopmental condition that causes inattention, impulsivity, and hyperactivity.

The Royal College of Psychiatrists state that ADHD tends to improve as a person grows up. For example, a person will typically become less hyperactive over time. However, they may still have difficulty concentrating, be impulsive, and take risks.

As a result, an adult with ADHD may find it difficult to learn, work, and get along with others. Adults with ADHD may also be more likely to experience anxiety, depression, and low self-esteem.

According to the Royal College of Psychiatrists, some symptoms of ADHD in adults include:

  • becoming easily distracted and finding it difficult to pay attention, especially when bored
  • finding it difficult to listen to other people, including interrupting and finishing their sentences
  • finding it difficult to follow instructions
  • finding it difficult to organize and finish activities
  • becoming restless and unable to sit still
  • being forgetful
  • becoming irritable, impatient, or frustrated easily
  • finding stressors difficult to deal with
  • being impulsive

According to the Centers for Disease Control and Prevention (CDC), healthcare professionals will diagnose adults with ADHD based on the criteria in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), which is a book that outlines the symptoms of mental health conditions.

Based on which symptoms a person experiences, a doctor will decide which of the three types of ADHD a person has. This might be:

  • Predominantly inattentive presentation: An individual may find it difficult to finish a task, pay attention to detail, or follow instructions. They may also find that they are easily distracted.
  • Predominantly hyperactive-impulsive presentation: An individual may talk a lot and fidget. They may feel restless and find it difficult to wait their turn.
  • Combined presentation: An individual may experience the symptoms of the above two types equally.

To receive a diagnosis of adult ADHD, a person will have to show five or more of the following symptoms for at least 6 months (which are typically inappropriate for that adult’s developmental level).

Inattentive presentation

They may often:

  • fail to pay close attention to details or make careless mistakes in work or other activities
  • have difficulty paying attention to tasks and activities
  • not appear to listen when a person speaks to them directly
  • not finish chores or duties in the workplace
  • have difficulty organizing activities and tasks
  • avoid, or be reluctant to do, tasks that require mental effort over a long period of time
  • lose things necessary for tasks and activities
  • get easily distracted
  • become forgetful in daily activities

Hyperactive-impulsive presentation

They may often:

  • fidget with their feet or hands or not be able to sit still
  • stand up when remaining seated is expected
  • become restless
  • be unable to quietly take part in leisure activities
  • be very active and “on the go”
  • talk a lot
  • interrupt questions
  • have difficulty waiting their turn
  • interrupt others

Other criteria

As well as experiencing some of the above symptoms, they must also:

  • have experienced several inattentive or hyperactive-impulsive symptoms before the age of 12
  • experience these symptoms in at least two settings, such as at home and at work
  • show that there is evidence that these symptoms are interfering with their daily activities
  • show that these symptoms are not the result of another mental health condition, such as anxiety or depression

According to the National Institute of Mental Health (NIMH), once a healthcare professional diagnoses ADHD, they are likely to prescribe medication and refer a person for therapy.

The following sections will discuss these treatments in more detail.


Medication usually consists of either stimulants or non-stimulants.

Stimulants increase the amount of dopamine and norepinephrine in the brain. These are two chemicals that make it easier for people to think and pay attention.

However, stimulants may not be suitable for people with high blood pressure, seizures, liver or kidney diseases, or anxiety disorders.

Non-stimulants take longer to work than stimulants, but they also improve focus and attention and reduce impulsivity.

Some doctors may prescribe both stimulants and non-stimulants to the same person to increase their effectiveness.


Doctors may also refer a person for therapy.

Behavioral therapy and cognitive behavioral therapy aim to help a person change their behavior patterns and teach them methods to reinforce their desired behaviors.

Doctors may also suggest that a person joins a support group.

The CDC explain that researchers are still unsure about what causes ADHD.

However, there is increasing evidence to suggest that genetics may play a part in who develops this condition and who does not.

As well as genetics, the following factors may increase the chance of a person having ADHD:

  • brain injury
  • exposure to environmental factors such as lead during pregnancy or at a young age
  • alcohol and tobacco use during pregnancy
  • low birth weight
  • premature birth

The CDC also suggest that there is currently no research that conclusively confirms that factors such as watching too much television, consuming too much sugar, or certain parenting practices cause ADHD.

Although these factors may make the symptoms worse, there is not enough evidence to say that these are main causes of ADHD.

According to one 2017 article, there are several conditions that adults with ADHD may also have.

These are:

Bipolar disorder

According to the NIMH, bipolar disorder and ADHD can coexist.

Bipolar disorder is a condition that causes people to be restless, talkative, and distractible. They may also have periods of depressive and manic moods.

The 2017 article states that between 9.5% and 21.2% of adults with bipolar disorder also have adult ADHD, and that between 5.1% and 47.1% of adults with ADHD have bipolar disorder.

Researchers suggest that having either ADHD or bipolar disorder under the age of 18 increases the likelihood that people will develop the other condition over time.


Depression is another condition that commonly coexists with ADHD.

Some research has suggested that between 18.6% and 53.3% of adults with ADHD also experience depression.

Adults with both ADHD and depression self-report that their quality of life is lower than that of those with depression alone.

Learn more about ADHD and depression here.


Adults with ADHD are more likely to also have anxiety than those who do not have ADHD.

The ADAA state that 50% of adults with ADHD also experience an anxiety disorder.

Adults with ADHD who also have a social phobia, such as fear when meeting or talking to people, are more common than adults with ADHD who also experience a panic disorder.

Substance use

According to the 2017 article, use of alcohol, nicotine, cannabis, or cocaine is one of the most common coexisting conditions with adult ADHD.

Some researchers suggest that substance use is twice as common in adults with ADHD as it is with those who do not have this condition.

The most common type of substance use among people with ADHD is cigarette use.

Adults with ADHD tend to have a stronger dependence on nicotine than adults who do not have ADHD.

People with ADHD are also more likely to use substances to manage their mood or help them sleep than people without this condition.

Personality disorder

The same 2017 study reports that more than 50% of adults with ADHD also have personality disorders, and that 25% of adults with ADHD have two or more personality disorders.

A person should see a doctor if they believe that they are experiencing any of the symptoms of ADHD and it is interfering with their daily activities.

Doctors can diagnose and manage the symptoms of ADHD so that people can carry on their daily activities without interruption.

ADHD is a neurodevelopmental condition that causes inattentiveness, hyperactivity, and impulsivity.

Doctors can diagnose ADHD if a person experiences enough of the symptoms outlined in the DSM-5, which is a book that details the symptoms of various mental health conditions.

Once a doctor has diagnosed ADHD, they can work with individuals to help them manage and treat the symptoms.

There are several other coexisting conditions that a person with ADHD may have. These include bipolar disorder, depression, and substance use.

A person should see a doctor if they believe that they are experiencing any symptoms of ADHD and those symptoms are interfering with their daily activities.

Doctors will prescribe medications, refer a person to therapy, or both.