#Today I saw a video on the YouTube channel again. And I found a mental illness, Attention deficit hyperactivity disorder (ADHD). Wow, it was so many kinds of mental illness.
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, or excessive activity and impulsivity, which are otherwise not appropriate for a person's age. Some individuals with ADHD also display difficulty regulating emotions or problems with executive function. For a diagnosis, the symptoms should appear before a person is twelve years old, be present for more than six months, and cause problems in at least two settings (such as school, home, or recreational activities). In children, problems paying attention may result in poor school performance. Additionally, there is an association with other mental disorders and substance misuse. Although it causes impairment, particularly in modern society, many people with ADHD can have sustained attention for tasks they find interesting or rewarding (known as hyperfocus).
Despite being the most commonly studied and diagnosed mental disorder in children and adolescents, the precise cause or causes are unknown in the majority of cases. Genetic factors are estimated to make up about 75% of the risk. Nicotine exposure during pregnancy may be an environmental risk. It does not appear to be related to the style of parenting or discipline. It affects about 5–7% of children when diagnosed via the DSM-IV criteria and 1–2% when diagnosed via the ICD-10 criteria. As of 2015, it was estimated to affect about 51.1 million people globally. Rates are similar between countries and depend mostly on how it is diagnosed. ADHD is diagnosed approximately two times more often in boys than in girls, although the disorder is often overlooked in girls because their symptoms can differ from those of boys. About 30–50% of people diagnosed in childhood continue to have symptoms into adulthood and between 2–5% of adults have the condition. In adults, inner restlessness, rather than hyperactivity, may occur. They often develop coping skills which make up for some or all of their impairments. The condition can be difficult to tell apart from other conditions, as well as to distinguish from high levels of activity that are still within the range of normal behaviors.
ADHD management recommendations vary by country and usually involve some combination of counseling, lifestyle changes, and medications. The British guideline only recommends medications as a first-line treatment in children who have severe symptoms and for medication to be considered in those with moderate symptoms who either refuse or fail to improve with counseling, though for adults medications are a first-line treatment. Canadian and American guidelines recommend behavioral management as a first-line treatment in preschool-aged children, while medications and behavioral therapy together are recommended after that. Treatment with stimulants is effective for at least 14 months; however, their long-term effectiveness is unclear and there are potentially serious side effects.
The medical literature has described symptoms similar to those of ADHD since the 18th century. ADHD, its diagnosis, and its treatment have been considered controversial since the 1970s. The controversies have involved clinicians, teachers, policymakers, parents, and the media. Topics include ADHD's causes and the use of stimulant medications in its treatment. Most healthcare providers accept ADHD as a genuine disorder in children and adults, and the debate in the scientific community mainly centers on how it is diagnosed and treated. The condition was officially known as attention deficit disorder (ADD) from 1980 to 1987, while before this it was known as hyperkinetic reaction of childhood.
| ADHD symptoms |
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| Inattention | Hyperactivity-impulsivity |
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- difficulty paying close attention to details
- has trouble holding attention on tasks
- has trouble organizing tasks and activities
- loses things necessary for tasks
- appears forgetful in daily activities
- has a shorter attention span and is easily distracted
- difficulty with structured schoolwork
- difficulty completing tasks that are tedious or time-consuming
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- unable to sit still
- fidgets, squirms in seat
- leaves seat in inappropriate situations
- takes risks with little thought for the dangers
- "on the go" or "driven by a motor"
- talking more than others
- often answers quickly
- has trouble waiting their turn
- interrupts or intrudes on conversations
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Inattention, hyperactivity (restlessness in adults), disruptive behavior, and impulsivity are common in ADHD. Academic difficulties are frequent as are problems with relationships. The symptoms can be difficult to define, as it is hard to draw a line at where normal levels of inattention, hyperactivity, and impulsivity end and significant levels requiring interventions begin.
According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), symptoms must be present for six months or more to a degree that is much greater than others of the same age and they must cause significant problems functioning in at least two settings (e.g., social, school/work, or home). The criteria must have been met prior to age twelve in order to receive a diagnosis of ADHD. This requires at least 6 symptoms of inattention or hyperactivity/impulsivity for those under 17 and at least 5 for those 17 years or older.
ADHD is divided into three subtypes: predominantly inattentive (ADHD-PI or ADHD-I), predominantly hyperactive-impulsive (ADHD-PH or ADHD-HI), and the combined type (ADHD-C).
A person with ADHD inattentive type has most or all of the following symptoms, excluding situations where these symptoms are better explained by another psychiatric or medical condition:
- Be easily distracted, miss details, forget things, and frequently switch from one activity to another
- Have difficulty maintaining focus on one task
- Become bored with a task after only a few minutes, unless doing something they find enjoyable
- Have difficulty focusing attention on organizing or completing a task
- Have trouble completing or turning in homework assignments, often losing things (e.g., pencils, toys, assignments) needed to complete tasks or activities
- Appear not to be listening when spoken to
- Daydream, become easily confused, and move slowly
- Have difficulty processing the information as quickly and accurately as others
- Struggle to follow instructions
- Have trouble understanding details; overlooks details
A person with ADHD hyperactive-impulsive type has most or all of the following symptoms, excluding situations where these symptoms are better explained by another psychiatric or medical condition:
- Fidget or squirm a great deal
- Talk nonstop
- Dash around, touching or playing with anything and everything in sight
- Have trouble sitting still during dinner, school, and while doing homework
- Be constantly in motion
- Have difficulty performing quiet tasks or activities
- Be impatient
- Blurt out inappropriate comments, show their emotions without restraint, and act without regard for consequences
- Have difficulty waiting for things they want or waiting their turn in games
- Often interrupt conversations or others' activities
Girls with ADHD tend to display fewer hyperactivity and impulsivity symptoms but more symptoms pertaining to inattention and distractibility. Symptoms of hyperactivity tend to go away with age and turn into "inner restlessness" in teens and adults with ADHD.
People with ADHD of all ages are more likely to have problems with social skills, such as social interaction and forming and maintaining friendships. This is true for all subtypes. About half of children and adolescents with ADHD experience social rejection by their peers compared to 10–15% of non-ADHD children and adolescents. People with attention deficits are prone to having difficulty processing verbal and nonverbal language which can negatively affect social interaction. They also may drift off during conversations, miss social cues, and have trouble learning social skills.
Difficulties managing anger are more common in children with ADHD as are poor handwriting and delays in speech, language, and motor development. Although it causes significant difficulty, many children with ADHD have an attention span equal to or better than that of other children for tasks and subjects they find interesting.
In children, ADHD occurs with other disorders about two-thirds of the time. Some commonly associated conditions include:
- Epilepsy
- Tourette's syndrome
- Autism Spectrum Disorder (ASD): this disorder affects social skills, ability to communicate, behavior, and interests. As of 2013, the DSM-5 allows for a simultaneous diagnosis of both ASD and ADHD.
- Anxiety Disorders have been found to occur more commonly in the ADHD population.
- Intermittent explosive disorders
- Learning disabilities have been found to occur in about 20–30% of children with ADHD. Learning disabilities can include developmental speech and language disorders and academic skills disorders. ADHD, however, is not considered a learning disability, but it very frequently causes academic difficulties.
- Intellectual disabilities
- Reactive attachment disorder
- Substance use disorders. Adolescents and adults with ADHD are at increased risk of substance abuse. This is most commonly seen with alcohol or cannabis. The reason for this may be an altered reward pathway in the brains of ADHD individuals. This makes the evaluation and treatment of ADHD more difficult, with serious substance misuse problems usually treated first due to their greater risks.
- Sleep disorders and ADHD commonly co-exist. They can also occur as a side effect of medications used to treat ADHD. In children with ADHD, insomnia is the most common sleep disorder with behavioral therapy the preferred treatment. Problems with sleep initiation are common among individuals with ADHD but often they will be deep sleepers and have significant difficulty getting up in the morning. Melatonin is sometimes used in children who have sleep-onset insomnia.
- Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD), which occur with ADHD in about 50% and 20% of cases respectively. They are characterized by antisocial behaviors such as stubbornness, aggression, frequent temper tantrums, deceitfulness, lying, and stealing. About half of those with hyperactivity and ODD or CD develop antisocial personality disorder in adulthood. Brain imaging supports that conduct disorder and ADHD are separate conditions.
- Primary disorder of vigilance, which is characterized by poor attention and concentration, as well as difficulties staying awake. These children tend to fidget, yawn, and stretch and appear to be hyperactive in order to remain alert and active.
- Sluggish Cognitive Tempo (SCT) is a cluster of symptoms that potentially comprises another attention disorder. It may occur in 30–50% of ADHD cases, regardless of the subtype.
- Stereotypic movement disorder
- Mood disorders (especially bipolar disorder and major depressive disorder). Boys diagnosed with combined ADHD subtype are more likely to have a mood disorder. Adults with ADHD sometimes also have bipolar disorder, which requires careful assessment to accurately diagnose and treat both conditions.
- Restless legs syndrome has been found to be more common in those with ADHD and is often due to iron deficiency anemia. However, restless legs can simply be a part of ADHD and require careful assessment to differentiate between the two disorders.
- People with ADHD have an increased risk of persistent bed-wetting.
- A 2016 systematic review found a well-established association between ADHD and obesity, asthma and sleep disorders, and tentative evidence for association with celiac disease and migraine, while another 2016 systematic review did not support a clear link between celiac disease and ADHD, and stated that routine screening for celiac disease in people with ADHD is discouraged.
Certain studies have found that people with ADHD tend to have lower scores on Intelligence Quotient (IQ) tests. The significance of this is controversial due to the differences between people with ADHD and the difficulty determining the influence of symptoms, such as distractibility, on lower scores rather than intellectual capacity. In studies of ADHD, higher IQs may be overrepresented because many studies exclude individuals who have lower IQs despite those with ADHD scoring on average nine points lower on standardized intelligence measures.
Studies of adults suggest that negative differences in intelligence are not meaningful and may be explained by associated health problems.
Most ADHD cases are of unknown causes. It is believed to involve interactions between genetics, the environment, and social factors. Certain cases are related to previous infection or trauma to the brain.
Twin studies indicate that the disorder is often inherited from the person's parents, with genetics determining about 75% of cases in children and 35% to potentially 75% of cases in adults. Siblings of children with ADHD are three to four times more likely to develop the disorder than siblings of children without the disorder.
Arousal is related to dopaminergic functioning, and ADHD presents with low dopaminergic functioning. Typically, a number of genes are involved, many of which directly affect dopamine neurotransmission. Those involved with dopamine include DAT, DRD4, DRD5, TAAR1, MAOA, COMT, and DBH. Other genes associated with ADHD include SERT, HTR1B, SNAP25, GRIN2A, ADRA2A, TPH2, and BDNF. A common variant of a gene called latrophilin 3 is estimated to be responsible for about 9% of cases and when this variant is present, people are particularly responsive to stimulant medication. The 7 repeat variant of dopamine receptor D4 (DRD4–7R) causes increased inhibitory effects induced by dopamine and is associated with ADHD. The DRD4 receptor is a G protein-coupled receptor that inhibits adenylyl cyclase. The DRD4–7R mutation results in a wide range of behavioral phenotypes, including ADHD symptoms reflecting split attention. The DRD4 gene is both linked to novelty-seeking and ADHD. People with Down syndrome are more likely to have ADHD. The genes glucose-fructose oxidoreductase domain-containing 1 (GFOD1) and cadherin 13 (CHD13) show strong genetic associations with ADHD. CHD13's association with autism, schizophrenia, bipolar disorder, and depression make it an interesting candidate causative gene. Another candidate causative gene that has been identified is adhesion-G protein-coupled-receptor-L3 (ADGRL3). In Zebrafish, knockout of this gene causes a loss of dopaminergic function in the ventral diencephalon, and the fish display a hyperactive/impulsive phenotype.
In order for genetic variation to be used as a tool for diagnosis, more validating studies need to be performed. However, smaller studies have shown that genetic polymorphisms in genes related to catecholaminergic neurotransmission or the SNARE complex of the synapse can reliably predict a person's response to stimulant medication. Rare genetic variants show more relevant clinical significance as their penetrance (the chance of developing the disorder) tends to be much higher. However, their usefulness as tools for diagnosis is limited as no single gene predicts ADHD. Autism spectrum disorders(ASD) show genetic overlap with ADHD at both common and rare levels of genetic variation.
Evolution may have played a role in the high rates of ADHD, particularly hyperactive and impulsive traits in males. Some have hypothesized that some women may be more attracted to males who are risk-takers, increasing the frequency of genes that predispose to hyperactivity and impulsivity in the gene pool. Others have claimed that these traits may be an adaptation that helps males face stressful or dangerous environments with, for example, increased impulsivity and exploratory behavior. In certain situations, ADHD traits may have been beneficial to society as a whole even while being harmful to the individual. The high rates and heterogeneity of ADHD may have increased reproductive fitness and benefited society by adding diversity to the gene pool despite being detrimental to the individual. In certain environments, some ADHD traits may have offered personal advantages to individuals, such as quicker response to predators or superior hunting skills. In the Ariaal people of Kenya, the 7R allele of the DRD4 gene results in better health in those who are nomadic but not those who are living in one spot.
In addition to genetics, some environmental factors might play a role in causing ADHD. Alcohol intake during pregnancy can cause fetal alcohol spectrum disorders which can include ADHD or symptoms like it. Children exposed to certain toxic substances, such as lead or polychlorinated biphenyls, may develop problems which resemble ADHD. Exposure to the organophosphate insecticides chlorpyrifos and dialkyl phosphate is associated with an increased risk; however, the evidence is not conclusive. Exposure to tobacco smoke during pregnancy can cause problems with central nervous system development and can increase the risk of ADHD.
Extreme premature birth, very low birth weight, and extreme neglect, abuse, or social deprivation also increase the risk as do certain infections during pregnancy, at birth, and in early childhood. These infections include, among others, various viruses (measles, varicella-zoster encephalitis, rubella, enterovirus 71). There is an association between long-term but not short-term use of acetaminophen during pregnancy and ADHD. At least 30% of children with a traumatic brain injury later develop ADHD and about 5% of cases are due to brain damage.
Some studies suggest that in a small number of children, artificial food dyes or preservatives may be associated with an increased prevalence of ADHD or ADHD-like symptoms, but the evidence is weak and may only apply to children with food sensitivities. The United Kingdom and the European Union have put in place regulatory measures based on these concerns. In a minority of children, intolerances, or allergies to certain foods may worsen ADHD symptoms.
Research does not support popular beliefs that ADHD is caused by eating too much refined sugar, watching too much television, parenting, poverty or family chaos; however, they might worsen ADHD symptoms in certain people.
The youngest children in a class have been found to be more likely to be diagnosed as having ADHD, possibly due to their being developmentally behind their older classmates. This effect has been seen across a number of countries. They also appear to use ADHD medications at nearly twice the rate as their peers.
In some cases, the diagnosis of ADHD may reflect a dysfunctional family or a poor educational system, rather than problems with the individuals themselves. In other cases, it may be explained by increasing academic expectations, with a diagnosis being a method for parents in some countries to get extra financial and educational support for their child. Typical behaviors of ADHD occur more commonly in children who have experienced violence and emotional abuse.
The social construct theory of ADHD suggests that because the boundaries between "normal" and "abnormal" behavior are socially constructed, (i.e. jointly created and validated by all members of society, and in particular by physicians, parents, teachers, and others) it then follows that subjective valuations and judgements determine which diagnostic criteria are used and, thus, the number of people affected. This could lead to a situation where the DSM-IV arrives at levels of ADHD three to four times higher than those obtained with the ICD-10. Thomas Szasz, a supporter of this theory, has argued that ADHD was " ... invented and then given a name".
ADHD is diagnosed by an assessment of a child's behavioral and mental development, including ruling out the effects of drugs, medications, and other medical or psychiatric problems as explanations for the symptoms. It often takes into account feedback from parents and teachers with most diagnoses begun after a teacher raises concerns. It may be viewed as the extreme end of one or more continuous human traits found in all people. Whether someone responds to medications does not confirm or rule out the diagnosis. As imaging studies of the brain do not give consistent results between individuals, they are only used for research purposes and no diagnosis.
In North America, DSM-5 criteria are used for diagnosis, while European countries usually use the ICD-10. With the DSM-IV criteria, a diagnosis of ADHD is 3–4 times more likely than with the ICD-10 criteria. It is classified as a neurodevelopmental psychiatric disorder. Additionally, it is classified as a disruptive behavior disorder along with oppositional defiant disorder, conduct disorder, and antisocial personality disorder. A diagnosis does not imply a neurological disorder.
Associated conditions that should be screened for include anxiety, depression, oppositional defiant disorder, conduct disorder, and learning and language disorders. Other conditions that should be considered are other neurodevelopmental disorders, tics, and sleep apnea.
Diagnosis of ADHD using quantitative electroencephalography (QEEG) is an ongoing area of investigation, although the value of QEEG in ADHD is currently unclear. In the United States, the Food and Drug Administration has approved the use of QEEG to evaluate ADHD. The approved test uses the ratio of EEG theta to beta activity to guide diagnosis; however, at least five studies have failed to replicate the finding.
Self-rating scales, such as the ADHD rating scale and the Vanderbilt ADHD diagnostic rating scale are used in the screening and evaluation of ADHD.
As with many other psychiatric disorders, formal diagnosis should be made by a qualified professional based on a set number of criteria. In the United States, these criteria are defined by the American Psychiatric Association in the DSM. Based on the DSM criteria, there are three subtypes of ADHD:
- ADHD predominantly inattentive type (ADHD-PI) presents with symptoms including being easily distracted, forgetful, daydreaming, disorganization, poor concentration, and difficulty completing tasks.
- ADHD, predominantly hyperactive-impulsive type presents with excessive fidgetiness and restlessness, hyperactivity, difficulty waiting, and remaining seated, immature behavior; destructive behaviors may also be present.
- ADHD, combined type is a combination of the first two subtypes.
This subdivision is based on the presence of at least six out of nine long-term (lasting at least six months) symptoms of inattention, hyperactivity-impulsivity, or both. To be considered, the symptoms must have appeared by the age of six to twelve and occur in more than one environment (e.g. at home and school or work). The symptoms must be inappropriate for a child of that age and there must be clear evidence that they are causing social, school, or work-related problems.
In the tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) by the World Health Organization, the symptoms of the hyperkinetic disorder are analogous to ADHD in the DSM-5. When a conduct disorder (as defined by ICD-10) is present, the condition is referred to as hyperkinetic conduct disorder. Otherwise, the disorder is classified as disturbance of activity and attention, other hyperkinetic disorders, or hyperkinetic disorders, unspecified. The latter is sometimes referred to the as hyperkinetic syndrome.
In the implementation version of ICD-11, the disorder is classified under 6A05 (Attention deficit hyperactivity disorder) and hyperkinetic disorder no longer exists.
Adults with ADHD are diagnosed under the same criteria, including that their signs must have been present by the age of six to twelve. Questioning parents or guardians as to how the person behaved and developed as a child may form part of the assessment; a family history of ADHD also adds weight to a diagnosis. While the core symptoms of ADHD are similar in children and adults they often present differently in adults than in children, for example, excessive physical activity seen in children may present as feelings of restlessness and constant mental activity in adults.
It is estimated that between 2–5% of adults have ADHD. Around 25–50% of children with ADHD continue to experience ADHD symptoms into adulthood, while the rest experience fewer or no symptoms. Currently, most adults remain untreated. Many adults with ADHD without diagnosis and treatment have a disorganized life and some use non-prescribed drugs or alcohol as a coping mechanism. Other problems may include relationship and job difficulties, and an increased risk of criminal activities. Associated mental health problems include depression, anxiety disorder, and learning disabilities.
Some ADHD symptoms in adults differ from those seen in children. While children with ADHD may climb and run about excessively, adults may experience an inability to relax, or they talk excessively in social situations. Adults with ADHD may start relationships impulsively, display sensation-seeking behavior, and be short-tempered. Addictive behavior such as substance abuse and gambling are common. The DSM-V criteria do specifically deal with adults, unlike those in DSM-IV, which were criticized for not being appropriate for adults; those who presented differently may lead to the claim that they outgrew the diagnosis.
Having ADHD symptoms since childhood is usually required to be diagnosed with adult ADHD. However, a proportion of adults who meet the criteria for ADHD would not have been diagnosed with ADHD as children. Most cases of late-onset ADHD develop the disorder between the ages of 12-16 and can therefore be considered early adult or adolescent-onset ADHD.
| ADHD symptoms which are related to other disorders |
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| Depression | Anxiety Disorder | Bipolar Disorder |
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- feelings of hopelessness, low self-esteem, or unhappiness
- loss of interest in hobbies or regular activities
- fatigue
- sleep problems
- difficulty maintaining attention
- change in appetite
- irritability or hostility
- low tolerance for stress
- thoughts of death
- unexplained pain
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- persistent feeling of anxiety
- irritability
- occasional feelings of panic or fear
- being hyperalert
- inability to pay attention
- tire easily
- low tolerance for stress
- difficulty maintaining attention
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- in manic state
- excessive happiness
- hyperactivity
- racing thoughts
- aggression
- excessive talking
- grandiose delusions
- decreased need for sleep
- inappropriate social behavior
- difficulty maintaining attention in a depressive state
- same symptoms as in the depression section
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Symptoms of ADHD, such as low mood and poor self-image, mood swings, and irritability, can be confused with dysthymia, cyclothymia, or bipolar disorder as well as with borderline personality disorder. Some symptoms that are due to anxiety disorders, antisocial personality disorder, developmental disabilities, or mental retardation or the effects of substance abuse such as intoxication and withdrawal can overlap with some ADHD. These disorders can also sometimes occur along with ADHD. Medical conditions which can cause ADHD type symptoms include hyperthyroidism, seizure disorder, lead toxicity, hearing deficits, hepatic disease, sleep apnea, drug interactions, untreated celiac disease, and head injury.
Primary sleep disorders may affect attention and behavior and the symptoms of ADHD may affect sleep. It is thus recommended that children with ADHD be regularly assessed for sleep problems. Sleepiness in children may result in symptoms ranging from the classic ones of yawning and rubbing the eyes, to hyperactivity and inattentiveness. Obstructive sleep apnea can also cause ADHD type symptoms. Rare tumors called pheochromocytomas and paragangliomas may cause similar symptoms to ADHD.
Reviews of ADHD biomarkers have noted that platelet monoamine oxidase expression, urinary norepinephrine, urinary MHPG, and urinary phenethylamine levels consistently differ between ADHD individuals and healthy control. These measurements could potentially serve as diagnostic biomarkers for ADHD, but more research is needed to establish their diagnostic utility. Urinary and blood plasma phenethylamine concentrations are lower in ADHD individuals relative to controls and the two most commonly prescribed drugs for ADHD, amphetamine, and methylphenidate, increase phenethylamine biosynthesis in treatment-responsive individuals with ADHD. Lower urinary phenethylamine concentrations are also associated with symptoms of inattentiveness in ADHD individuals. Electroencephalography (EEG) is not accurate enough to make the diagnosis.
Hyperactivity has long been part of the human condition. Sir Alexander Crichton describes "mental restlessness" in his book An inquiry into the nature and origin of mental derangement written in 1798. He made observations about children showing signs of being inattentive and having the “fidgets”. The first clear description of ADHD is credited to George Still in 1902 during a series of lectures he gave to the Royal College of Physicians of London. He noted both nature and nurture could be influencing this disorder.
Alfred Tredgold proposed an association between brain damage and behavioral or learning problems which were able to be validated by the encephalitis lethargica epidemic from 1917 through 1928.
The terminology used to describe the condition has changed over time and has included: in the DSM-I (1952) "minimal brain dysfunction," in the DSM-II (1968) "hyperkinetic reaction of childhood," and in the DSM-III (1980) "attention-deficit disorder (ADD) with or without hyperactivity." In 1987 this was changed to ADHD in the DSM-III-R and the DSM-IV in 1994 split the diagnosis into three subtypes, ADHD inattentive type, ADHD hyperactive-impulsive type, and ADHD combined type. These terms were kept in the DSM-5 in 2013. Other terms have included "minimal brain damage" used in the 1930s.
In 1934, benzedrine became the first amphetamine medication approved for use in the United States. Methylphenidate was introduced in the 1950s and enantiopure dextroamphetamine in the 1970s. The use of stimulants to treat ADHD was first described in 1937. Charles Bradley gave the children with behavioral disorders Benzedrine and found it improved academic performance and behavior.
Until the 1990s, many studies "implicated the prefrontal-striatal network as being smaller in children with ADHD". During this same period, a genetic component was identified, and ADHD was acknowledged to be a persistent, long-term disorder that lasted from childhood into adulthood. ADHD was split into the current three sub-types because of a field trial completed by Lahey and colleagues.
