Everything You Need to Know About ADHD

By Olivia Guy-Evans, published May 20, 2022 | Fact Checked by Saul Mcleod, PhD

Human head with many thoughts, task and ideas. Child or adult with ADHD syndrome. Attention deficit hyperactivity disorder. Mental health, psychology concept. Vector flat style illustration.

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition. This condition is categorised by developmentally inappropriate levels of inattention, impulsivity, and hyperactivity.

It is common for everyone to experience some level of difficulty with attention or with controlling impulsive behaviour, but for those with ADHD, the problems are so pervasive and persistent that they can interfere with every aspect of their lives.

The first known documentation of ADHD is from 1902 where it was coined for some children. Since then, the condition has been given numerous names, one of these being attention deficit disorder (ADD).

ADD is often still used today although the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) only lists ADHD to describe individuals with this condition, regardless of whether they display symptoms of hyperactivity.

ADD vs ADHD: What are the Differences?

ADHD is usually first diagnosed in childhood, believed to affect around 11% of school-aged children.

Children with ADHD usually have difficulties concentrating on the task at hand, find that their attention can shift between several things at once, and they may be unable to sit still for long periods of time.

The symptoms for ADHD are thought to continue into adulthood for more than three quarters of the cases (Brown, 2013).

Whilst the symptoms can change with time, they can still interfere with an adult’s functioning, specifically in their relationships, health, work, and finances.


ADHD symptoms in adults onboarding mobile app page screen set. Hyperactive kid signs walkthrough 5 steps graphic instructions with concepts. UI, UX, GUI vector template with linear color

ADHD symptoms in adults onboarding mobile app page screen set. Hyperactive kid signs walkthrough 5 steps graphic instructions with concepts. UI, UX, GUI vector template with linear color

Below are some of the common experiences and traits individuals with ADHD may report:

  • Tasks, homework, or chores tend to take them a long time to complete

  • Often forgetful – they may forget birthdays, instructions, or homework

  • They are often accused of not trying or appearing to not care

  • Appear to underachieve in areas of life where they may have a lot of potential

  • Have a low tolerance for boredom

  • Issues with time management such as getting up, getting to work or school on time, or getting to appointments

  • They may miss important information because they have ‘zoned out’

  • They may hyper-focus on tasks that interest them, to the detriment of important activities like sleep and social interaction

  • Might find reading a book from start to finish challenging or may find it difficult to take in what they have read

  • They may face financial problems due to impulsive spending and forgetting to pay bills

  • They may have trouble getting to sleep, staying asleep, and waking up on time

  • Often might not trust themselves to do what they say they will 

  • May have low-self-esteem after years of not meeting their own and other people’s expectations. 

  • Problems with executive function and working memory

ADHD can present differently in children and adults. In children, the symptoms of ADHD can typically cause problems in school such as getting low grades or getting into trouble for disruptive behaviours.

Children with ADHD may often experience delays in independent functioning and may behave younger than their peers. Many children may have mild delays in language, motor skills, or social development.

Likewise, children with ADHD may have lower frustration tolerance, difficulty controlling their emotions, and may often experience mood swings. 

In adulthood, ADHD can change to some extent. The hyperactive symptoms can become less visible, finding they can relatively sit still despite any internal restlessness.

This internal restlessness be in the form of rapid and changing thinking, thoughts, and ideas. The inattentive symptoms of ADHD usually remain consistent although adults can usually have more control over their environments than children.

Whilst children typically must remain sitting at a desk most of the day, some adults can design a life or choose a job which suits their ADHD symptoms.

So, instead of choosing a career that involves sitting at a desk, they may choose a career that involves moving around, physical labour, or travelling to different places for work.

In adults with ADHD, they may find they have difficulties with their peers and social situations, have inconsistent performance at work, engage in risky sexual behaviours, and have chronic feelings of frustration, guilt, or shame.

Some of the negative outcomes of ADHD may include losing a job that they are not suited for, becoming bankrupt due to issues managing finances, marriage problems, and addictions. 

Types of ADHD

The DSM-5 criteria for ADHD lists three presentations of the condition that people who have the condition fall into: predominantly inattentive presentation, predominantly hyperactive-impulsive presentation, and combined hyperactive-impulsive and inattentive presentation.

Below are the types of presentations and some of the traits associated with each one.

ADHD predominantly inattentive presentation

  • Has significant difficulty sustaining attention

  • Do not appear to be listening in conversations

  • Fails to give close attention to details or makes careless mistakes

  • Finds themselves easily distracted

  • Tends to lose things often, such as their keys or phone

  • Struggles to follow through with instructions

  • Has difficulty with organisation

  • Dislikes tasks which require sustained mental effort and may avoid these tasks

  • Has difficulty completing a task from start to finish

  • Can be very forgetful in daily activities

  • Often procrastinates from tasks

ADHD predominantly hyperactive-impulsive presentation

  • Has difficulty remaining seated

  • Fidgets with their hands or feet

  • In children - often runs about or climbs excessively

  • In adults – extreme restlessness

  • Talks excessively

  • Has difficulty engaging in activities quietly

  • Act as if driven by a motor

  • Gives or shouts out answers to questions before the questions have been completed

  • Difficulty waiting or taking turns

  • Interrupts others

  • Excessively high levels of activity which may present as physical and/or verbal overactivity

  • Tend to dominate conversations

  • Behaviours can be loud and disruptive

ADHD combined presentation

This is where the individual meets the criteria for both the inattentive and hyperactive-impulsive presentations. 


There is no single test for ADHD therefore a comprehensive evaluation is necessary to establish a diagnosis, rule out other causes, and determine the presence of co-existing conditions.

An evaluation can take a long time and should include a thorough history of the individual and a clinical assessment of the individual’s academic, social, and emotional functioning and developmental level.

Some of the professionals that can diagnose ADHD include:

  • Clinical psychologist

  • Clinical social workers

  • Nurse practitioners

  • Neurologists

  • Psychiatrists 

  • Paediatricians 

It can prove complicated to diagnose ADHD in children as many conditions can contribute to similar symptoms, such as anxiety, depression, and certain types of learning disorders.

A thorough history of the child should be obtained from the parents and teachers, and where appropriate, from the child. 

Although some ADHD symptoms are evident in early childhood, some may not experience significant problems until later in life.

For adults, diagnosis also involves gathering information from multiple sources, including ADHD symptom checklists, standardised behaviour rating scales, a detailed history of past and current functioning, and information obtained from people who know the person well.

Adults may seek a diagnosis when they have experienced significant problems in one or more areas of living, such as in their job or career, academic underachievement, or relationships. 

A comprehensive evaluation for ADHD should include a thorough diagnostic interview, using structured or semi-structured interviews. Many professionals may also ask individuals to complete questionnaires before their evaluation.

The interviewer should ask pre-determined, standardised sets of questions in order to increase reliability and to decrease the chances that a different interviewer would come to a different conclusion.

For a diagnosis to be met, the DSM-5 criteria states that there must be a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.

This is characterised by 6 or more of the predominately inattention presentation symptoms, or of the predominantly hyperactivity and impulsivity symptoms, or both.

These symptoms must have persisted for at least 6 months to a degree that is inconsistent with developmental levels and negatively impacts directly on social and academic/occupational activities.

Several of the inattentive or hyperactive-impulsive symptoms must have been present prior to the age of 12 years and must be present in two or more settings (e.g., at home, school, or work; with friends or relatives; in other activities).

For a diagnosis, the ADHD symptoms evidently interfere with, or reduce the quality of, social, academic, or occupational functioning.

Also, the symptoms should not be better explained by another mental disorder such as mood, anxiety, or personality disorders. Moreover, the professionals would have to specify whether the severity of the symptoms, whether these are mild, moderate, or severe. 


There is uncertainty surrounding the causes of ADHD, although it is generally believed to have neurological and genetic origins. More than 20 genetic studies have demonstrated evidence that ADHD is strongly inherited.

causes of ADHD

This means that if someone has ADHD there is a good chance that they have a family member who also has the condition. 

Research suggests that there is a structural difference in the brains of those with ADHD compared to those who do not have the condition (Bonath et al., 2016).

It was found that those with ADHD had reduced grey matter volumes in their anterior cingulate cortex, occipital cortex, cerebellar regions, and bilateral hippocampus/amygdala.

This reduction in grey matter volume could be an explanation for why people with ADHD have attentional problems, since grey matter is involved in learning, memory, cognitive processes, and attention. 

There are believed to be some factors in the environment which may increase the likelihood of someone having ADHD:

  • Exposure to lead or pesticides in early childhood

  • Premature birth or low weight at birth

  • Brain injury

It has been believed in the past that certain environmental factors may cause ADHD, although these have not been found to be the case.

Some of the factors that do NOT cause ADHD but may make the condition worse include watching excessive amounts of TV, eating sugar, family stress, parenting styles, and traumatic experiences.

Even though environmental factors such as family stress does not cause ADHD, it can change the way ADHD presents itself and may result in additional problems such as anti-social behaviours (Langley et al., 2010). 

Researchers are continuing to study the exact relationship between ADHD and environmental factors but point out that there is no single cause that can account for all cases of ADHD. 

Underlying differences in the brain are likely to be an underlying cause of ADHD, with some researchers looking at dopamine as a possible contributor.

Dopamine is a neurotransmitter of the brain which functions to regulate emotional responses and is involved in motivation, feelings of pleasure, and rewards. 

It has been observed that levels of dopamine are different in people with ADHD. A study which used the neuroimaging technique of positron emission tomography (PET) found that there was a significant reduction in dopamine synaptic markers in the dopamine reward pathways of those with ADHD, and that this may be associated with symptoms of inattention (Volkow et al., 2009).

One of the dopamine pathways in the brain, the mesoaccumbens dopamine pathway, which projects from the ventral tegmental area (VTA) to the nucleus accumbens (involved in reward and motivation), has been hypothesised to underlie the reward and motivational deficits observed in ADHD (Johansen, et al., 2009). 

Researchers believe that the differences in the levels of dopamine is due to the neurons in the brains of those with ADHD have higher concentrations of proteins called dopamine transporters.

The concentration of these proteins is known as dopamine transporter density (DTD). The role of dopamine transporters is to reuptake dopamine from the synaptic cleft during neurotransmission so that dopamine does not reach the next neuron and influence the brain.

A higher DTD results in a lowering of dopamine levels in the brain which may be a risk factor for ADHD. One of the first known studies of DTD in 1999 measured DTD in 6 adults with ADHD. There was shown to be a 70% increase in DTD compared with those without ADHD (Dougherty et al., 1999).

A more recent study in 2015 suggested that the dopamine transporter DAT1 may specifically influence ADHD-like traits. However, this may only be the case for mood instability traits (Jeong et al., 2015). 

Co-existing conditions

More than two-thirds of people who have ADHD also have at least one other co-existing condition. Occasionally, ADHD may overshadow other conditions, making it harder to notice.

Likewise, the other condition may overshadow ADHD, making it harder to recognise ADHD symptoms. 

Disruptive behaviour disorders

About 40% of people who have ADHD also have oppositional defiant disorder (ODD). Symptoms of this condition involve arguing, losing one’s temper, a refusal to follow rules, a tendency to blame others, anger, being vindictive, and being spiteful. 

Conduct disorder (CD) is another behavioural disorder which can occur in around 27% of children, 45-50% of adolescents, and 20-25% of adults with ADHD.

Children and adolescents with CD may be aggressive to others, destroy property, lie, steal, or skip school. Adults, meanwhile, may exhibit behaviours which can get them in trouble with the law. 

Mood disorders

Studies suggest that up to 53.3% of adults with ADHD may also have depression (Katzman et al., 2017).

Approximately 14% of children with ADHD have depression compared to 1% of children without ADHD. Up to 20% of those with ADHD may also show signs of bipolar disorder.

Typically, the ADHD symptoms will occur first, followed by the mood disorder, perhaps because of the struggles those with ADHD face. 


Up to 30% of children and 53% of adults with ADHD may also have an anxiety disorder. Some anxiety disorders include generalised anxiety disorder, social anxiety, and obsessive-compulsive disorder (OCD).

People with ADHD may find it difficult to keep up with daily tasks and make and maintain relationships so this could increase anxious feelings as a result.

Likewise, people with ADHD are more likely to experience an anxiety disorder compared to those without ADHD. 

Tic and Tourette syndrome

Less than 10% of those with ADHD have tics or Tourette syndrome but over 60-80% of those with Tourette syndrome have ADHD.

Tics include sudden, rapid, involuntary movements or vocalisations. Tourette syndrome is rarer but most severe, involving making involuntary noises, or movements on an almost daily basis for years. 

Learning disorders

Up to 50% of people with ADHD have a learning disorder whereas 5% of children without ADHD have a learning disorder, making this a common condition.

Types of common learning disorders include dyslexia and dyscalculia and can involve problems with how individuals acquire or use new information. 12% of children with ADHD have speech problems compared with 3% of those without ADHD.

These extra challenges can make it harder for a child to manage at school and can worsen feelings of anxiety and depression. 


Treating ADHD often required medical, educational, and psychological intervention. This comprehensive approach is sometimes called ‘multimodal’ and depending on the age of the individual, may include:

  • Parent training

  • Medication 

  • Skills training

  • Counselling 

  • Behavioural therapy

  • Educational supports

  • Educational regarding ADHD


Medications for ADHD can come in either stimulant or non-stimulant types. Stimulants can help people with ADHD as these individuals are believed to have chronically under aroused brains. A type of stimulant includes methylphenidates which are found in Ritalin.  T

his type of stimulant is known as a dopamine reuptake inhibitor. This means that they stop dopamine from being absorbed back into the neuron which released it, meaning there is more circulating the brain. Amphetamines are another type of stimulant found in Adderall and Vyvanse.

These stimulate the neurons so that they release more dopamine. Both types of stimulants increase levels of dopamine to a more ‘neurotypical’ level so there is less need to find stimulation from the environment, making it easier to focus.

Stimulants are more commonly prescribed for ADHD, but they can come with some potential side effects such as addiction in higher doses, sleep problems, or heart problems. 

Non-stimulant medication is not as prescribed as stimulant medications and are more often useful for those with severe anxiety. As the name suggests, these do not stimulate the central nervous system in the same way the stimulants do.

Most popular non-stimulant medication for ADHD is Wellbutrin (Bupropion) which is a norepinephrine-dopamine reuptake inhibitor (NDRI), a type of antidepressant. Likewise, Strattera (Atomoxetine), a selective norepinephrine reuptake inhibitor (SNRI) which is also a type of antidepressant. NDRIs block the action a specific transporter protein, increasing the amount of norepinephrine and dopamine in the brain.

SNRIs increase the levels of norepinephrine in the brain by blocking the reuptake of this type of neurotransmitter so there is more circulating the brain. 

Behaviour therapy

For some, behaviour therapy can help people with ADHD learn the skills required to control their symptoms and help them manage tasks.

The goal of behaviour therapy is to replace negative behaviours with positive ones. This therapy can teach people strategies to improve problem areas like organisation, focus, impulse control, or anything else that is an issue for those with ADHD.

Many find that behaviour therapy can help them effectively manage their ADHD symptoms without the use of medications. Although behaviour therapy does not affect brain chemistry, it can teach people skills that make it easier to navigate at school, work, home, and in relationships. 

For children, behaviour therapy usually uses the whole family approach to change behaviours. This therapy can also investigate how negative actions are responded to in a child’s home.

Sometimes the parents can be unintentionally reinforcing negative behaviours, therefore a whole family approach can ensure the primary people in the child’s life know how to manage negative behaviours and reinforce positive ones. 

Cognitive behavioural therapy

According to the Centers for Disease Control and Prevention (CDC), behavioural therapy, as well as cognitive behavioural therapy (CBT) are helpful in reducing symptoms in children with ADHD. 

With adults, they are usually advised to have CBT which is similar to behaviour therapy but includes the negative and unhelpful thoughts which go alongside their behaviours.

CBT can help people to recognise how their own thoughts affect their behaviours so they are able to reframe these thoughts, so they have more positive or realistic ones and thus more control over their symptoms. 

CBT involves working with a therapist to notice any thought and behavioural patterns, challenge negative thoughts, cope with stress, deal with stressful obligations, and learn new ways to manage everyday life.

As well as helping with ADHD, CBT can help people to manage other conditions which may coexist alongside their ADHD, such as mood and anxiety disorders. 

How to cope with ADHD

Alongside medicative and therapeutic treatments, there are some ways in which individuals with ADHD can implement into their lives to help manage or cope with their symptoms and to navigate everyday life:

  • Having a consistent schedule with structure and regular expectations. 

  • Making lists of things which need doing on a daily basis and adding to them when new ideas emerge.

  • Keeping a calendar and setting reminders to minimise the chance that important events or appointments get forgotten.

  • For a child – they can write down homework assignments and keep everyday items such as toys and backpacks in assigned spots, so they are less likely to get lost. A parent of a child can also establish structure around meals, homework, and playtime.

  • Break tasks into manageable pieces and ensuring regular break times where possible can help with feeling overwhelmed. Taking breaks when studying or working and leaving the room, going for a walk, or doing another task, can help to let out energy and help with feelings of boredom and lack of focus.

  • Simplify and organise life – e.g., assign specific quiet places to read or undertake a hobby to take a break from everyday chaos.

  • Reduce unnecessary distractions – distractions such as TV and video games could encourage impulsive behaviours and can be better regulated. 

  • Undertaking regular exercise which can help to burn energy and stimulate the brain in a healthy way. This can help to focus attention on specific movements and decrease impulsivity, help concentration, and decrease risk of anxiety or depression.

  • Regulate sleeping patterns – cutting down on sugar, caffeine, and screen-time as much as possible can help with establishing a sleep pattern as a lack of sleep can exacerbate inattention, hyperactivity, and recklessness. 

  • Promoting wait times – pausing to consider actions can encourage thoughtful responses.

  • Breathing exercises in times of feeling overwhelmed or when the brain is having multiple thoughts at once can help to calm down.

  • Other relaxation exercises such as yoga, tai chi, mindfulness, meditation, and spending time outdoors can help calm overactive minds and ease symptoms.

ADHD in females

ADHD is a condition which is more commonly diagnosed in males than females, typically three times as many males are diagnosed.

This may have led to some stereotypes that ADHD is a condition associated with boys who cannot keep still and are disruptive. However, it is likely that there are many girls and women who are not diagnosed because their symptoms of ADHD are being missed.

The discrepancy that males are diagnosed more than girls on a ratio of 3:1 highlights that a large number of girls with ADHD are likely to remain unidentified and untreated.

This leads to implications that without a diagnosis, girls are likely to suffer more long-term social, educational, and mental health outcomes. 

Much of the available evidence on ADHD often draws on predominantly male-based samples due to the presumably higher prevalence of ADHD in males. However, it seems to be the case that girls with autism display their symptoms differently to boys.

Girls often tend to display less severe symptoms of ADHD than boys, especially when it comes to hyper-activity and impulsivity. More girls with ADHD may fall more into the predominantly inattentive presentation of ADHD.

ADHD symptoms in adults onboarding mobile app page screen set. Hyperactive kid signs walkthrough 5 steps graphic instructions with concepts. UI, UX, GUI vector template with linear color

The inattention symptoms may present as being easily distracted, overwhelmed, lacking in effort, and motivation.

The less overt symptoms of ADHD in girls means that they are less likely to be obvious to others, meaning that they are less likely to get a referral for an evaluation.

Symptoms of ADHD may become more obvious in females later in life, often during periods of social or educational transitions or when trying to navigate the world of work. 

A 2020 consensus summarised key point for the detection of ADHD in females:

  • Females present with both inattentive and hyperactive-impulsive symptoms

  • Symptom severity may be lower in females than in males, particularly for hyperactive-impulsive symptoms

  • Low mood, emotional lability or anxiety may be especially common in females with ADHD

  • Emotional regulation problems may be more severe/common in girls with ADHD

  • Girls with ADHD are vulnerable to bullying

  • There is an increased school drop-out and academic underachievement

  • They tend to have decreased self-esteem and self-concept

  • They may not show as many behavioural problems commonly associated with males

  • Compensatory behaviours may mask behaviours and impairments

  • Dysfunctional strategies such as drinking alcohol or drug use may be used to cope with emotional problems, social isolation, and rejection (Young et al., 2020).

In many cases, girls with ADHD may also daydream frequently and be hyper-talkative rather than hyperactive.

Some girls and women with ADHD become competent at camouflaging their struggles using compensatory strategies which may result in an underestimation of their underlying problems. Often their strategies have an adaptive or functional purpose such as enabling them to remain focused or sustain attention for periods of time.

Not all strategies are helpful such as avoiding specific events, settings, or people, not facing up to problems, spending too much time online, or not seeking help when needed. 

It’s not uncommon that females with ADHD are treated for anxiety or depression in the first instance.

Since some of the symptoms of ADHD and other conditions can be similar, if females have less severe ADHD symptoms or they are masking their symptoms, this could be mistaken for another condition. Likewise, they may actually have a co-existing condition, but this overshadows their ADHD, so it goes unnoticed. 

One of the benefits of females being diagnosed with ADHD is that it can lift the shame and guilt they may have felt about their symptoms. They can understand more about why they acted in certain ways in the past and can seek treatment or management options for their symptoms.

Similarly, before a diagnosis, girls may have been given labels such as ‘chatterbox’, ‘drama queen’ or ‘tomboy’. Having a diagnosis of ADHD can help free them from these labels that may have been attributed to them. 

To conclude, it is important not to discount ADHD in females because they do not display the behavioural problems commonly associated with males.

It is necessary to move past the idea that ADHD is a behavioural disorder and attention must be given to the more subtle and/or internalised presentation that is common in females. 

Fact Checking

Content is rigorously reviewed by a team of qualified and experienced fact checkers. Fact checkers review articles for factual accuracy, relevance, and timeliness. We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. Content is fact checked after it has been edited and before publication.

Cite this Article (APA Style)

Guy-Evans, O. (2022, May 20). Everything You Need to Know About ADHD. Simply Psychology. www.simplypsychology.org/ADHD.html


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