Attention deficit hyperactivity disorder in adults (adult ADHD)

• Disease Site
• Incidence
• Predisposing Factors
• Macroscopic Features
• Natural History
• Clinical History
• Clinical Examination
• Specific Investigations
• Prognosis
• References

Disease Site

Attention deficit hyperactivity disorder (ADHD) is a neurobehavioural syndrome characterised by hyperactivity, impulsivity and/or inattention.^1-4 While these symptoms are experienced by all people from time to time, they are severe and persistent in those with ADHD, and therefore interfere with these individuals’ normal functioning.^1,2,4,5

Individuals who suffer from ADHD often have difficulty functioning in social, academic and occupational environments. They may struggle to follow directions, remember information, concentrate, organise tasks or complete work within time limits.^1-4

Although best known as a condition of children in preschool and early school years, the presence of ADHD is increasingly recognised in some adults as a remnant of their childhood condition. Adult ADHD was first observed in 1976, and first included in the Diagnostic and Statistical Manual of Mental Disorders as a condition distinct from the childhood disorder in 1987.⁶

Incidence

Between 30% and 70% of children with ADHD will continue to display symptoms of the disorder in adulthood.² Conservative prevalence rates estimate that nearly 1 in 20 adults in the general population have ADHD.⁷ The National Comorbidity Survey Replication (NCSR), a nationally represented household survey in the United States, estimated the prevalence of ADHD at 4.4% in adults aged 18–44.⁷ Based on Australian population figures, it is estimated that over 360,000 Australians between the ages of 18 and 44 have ADHD.⁸

In 2003, less than 0.1% of the adult population were prescribed stimulant medication for ADHD. This represents a rate of 7 per 10,000 adults and highlights the significant under-diagnosis of the disorder.⁹

It is interesting to note that the adult condition is equally prevalent in men and women.¹⁰ However, for every adult female on stimulant medication, there are 1.7 adult males on stimulants.⁹ This shows the condition is undertreated in women.

As there is no evidence to suggest differences in the rate of remission between men and women, it may also reflect under-diagnosis of ADHD in girls.¹⁰

 

For more information on ADHD in children, see Childhood ADHD.

 

 

Predisposing Factors

ADHD is a persistent condition that arises in early childhood. Adults who were diagnosed with or have experienced the symptoms of ADHD as are more likely to have ADHD as adults.² There is, however, no evidence of adult onset.⁶ The following is a summary of predisposing factors of ADHD for children which has the potential to extend to adulthood.

Genetic factors

There is a large body of evidence from genome-wide linkage studies to support the hereditary nature of ADHD with an average concordance rate of 0.76.¹¹ Furthermore, it is believed that the genetic influence is more strongly associated in the cases that persist to adulthood compared to those which subside during adolescence. While it is clear that the aetiology of ADHD has a strong genetic component and many genes have been linked to the condition, the extent of neurotransmitter gene involvement is still largely unknown, such as which of these are indicated in certain ADHD subtypes.¹²

ADHD is a complex trait which makes identifying specific genes associated with the disorder difficult. For example, recent studies have looked at the genes associated with different ADHD subtypes, revealing that the interactions between certain genes in specific environments for specific ADHD subtypes are thought to display variations. So far, there have been over 215 genes associated with ADHD, yet none of the gene variations currently studied have presented as sole mediators of the disorder.¹¹

That being said, there have been some noticeable genes that have been identified as predisposing factors to the disorder. Genetic research to date has focused largely on dopaminergic genes, due to the hypothesised influence of dopamine in behavioural disorders and as a target for ADHD treatment. Increased levels of dopamine activity are also seen during neuroimaging of the ADHD brain. Polymorphisms of the dopamine transporter (DAT) gene, as well as the D4 and D5 receptor genes, have been linked to the aetiology of ADHD.¹²

Decreased serotonin is associated with poor arousal and, accordingly, a subset of serotonergic genes have also been identified as promising candidate genes, including the serotonin transporter gene and the serotonin 2A receptor gene.¹²

Environmental and family factors

Children who have a genetic predisposition are more likely to express symptoms of the disorder when exposed to certain environments.⁵

Exposure to cigarettes, alcohol and other substances (e.g. cocaine) during pregnancy, may increase the risk of ADHD. Preschool children with higher levels of lead in their bodies are also at a higher risk of developing ADHD.²

Chaotic parenting may increase the risk of developing ADHD, but the relationship between ADHD and parenting may result from both negative aspects of the child influencing the parents’ behaviour, as well as the parents influencing the child’s behaviour. The behaviour of parents who are more demanding, aversive, negative, controlling, intrusive, disapproving, power assertive, and less rewarding has been shown to exacerbate ADHD symptoms.⁵

Children from lower socioeconomic classes have higher rates of ADHD, and are more likely to be undertreated for their disorder. The increased rates of ADHD in poorer children is thought to relate to varying exposure to risk factors (e.g. in utero tobacco exposure, childhood lead exposure, complications of pregnancy and delivery). In addition, the heritable nature of ADHD and its negative impact on social, academic and career outcomes may cause ADHD sufferers to cluster in lower socioeconomic groups.¹

Addressing these predisposing factors should form part of future health prevention strategies.

Congenital factors

Studies have shown a possible link between the use of cigarettes and alcohol during pregnancy, and the risk of ADHD in offspring. Maternal substance abuse (e.g. cocaine, nicotine) may also be associated with ADHD-like symptoms.²

Pregnancy and delivery complications (e.g. prematurity) have been linked with increased rates of ADHD.¹

Acquired brain injury can also increase the risk of ADHD.¹³

Brain structure factors

Some studies suggest that ADHD is caused by a compromised structure in areas of the brain that relate to inhibition and attention. Studies show that the brain circuits linking the prefrontal cortex, striatum and cerebellum are malfunctioning in children with ADHD.¹⁴

Another study, a case-control study of ADHD children matched by age and sex to non-ADHD controls, reported reduced brain size amongst ADHD children, mainly in the posterior but also in the anterior regions of the brain. The study used magnetic resonance imaging to map regional brain size and grey matter abnormalities. It also reported prominent increases in grey matter in the posterior temporal and inferior parietal cortices bilaterally.¹⁵

Neurophysiological factors

ADHD symptoms may be a result of cognitive deregulation, where the child’s behaviour results from insufficient forethought, planning and control, leading to impulsive responses and higher error rates.⁵

Another explanation of the impulsive response is the ‘delay aversion’ hypothesis, in which the child makes a more impulsive response because it allows the faster completion of a task, and therefore avoids delay.⁵

In a situation where the child is not in control (e.g. in a classroom where he/she is expected to behave in a certain way), the child could achieve control by either daydreaming (inattention) or by fidgeting (hyperactivity).⁵

Dietary factors

ADHD has been linked to the intake of food additives, food colourings and refined sugar. These substances have been shown to exacerbate ADHD symptoms. Diets that exclude foods containing substances which exacerbate behavioural problems, such as the Australian-developed FAILSAFE diet, have been used as treatment for ADHD since the 1980s.¹⁸ While the association between diet and ADHD symptoms is clear, dietary interventions alone have proven insufficient to treat the symptoms of ADHD, and are best used in combination with pharmacological and educational interventions.⁵

Children with iron deficiency have more severe symptoms of ADHD than those without iron deficiency.¹⁷

Macroscopic Features

There are noted differences in the brains of individuals with ADHD,¹⁰ with abnormalities in brain structure and functioning directly impacting behaviour. Meta-analysis of ADHD research, which included more than 6,000 participants, indicated that many with ADHD have impairment of executive functioning, specifically in response inhibition, vigilance, working memory, and some areas of planning.¹⁹ In addition, adults with ADHD suffer from difficulties with sustained attention and concentration, internal restlessness and agitation, impulsivity in cognition and behaviour, rapidly changing moods, and irritability.²⁰

Natural History

ADHD in adults persists from childhood. Some adults grow up with ADHD that was diagnosed in childhood, while others remain unaware that they have the disorder.² Adult ADHD shares many characteristics with the childhood disorder, although adults are often more capable of controlling behaviour and masking difficulties. A child who is always ‘on the go’ may grow up to become an adult who is less obviously hyperactive, but who experiences intense feelings of restlessness and problems relaxing. Therefore, they are more prone to overworking themselves. Other adults may display impatience when in queues or while driving, and impulsiveness in quitting jobs and spending. They may often complain of losing things (e.g. keys, wallets), of being late for appointments, or of forgetting important things (e.g. picking up children or paying utility bills).¹⁸

These symptoms lead to higher rates of divorce, traffic offences, substance abuse and over-eating. However, up to 30% of adults with ADHD direct their excess energy towards work and attain success in challenging professions and entrepreneurship.¹⁸

Core behavioural symptoms of ADHD

The behavioural symptoms of ADHD can be classified by three core symptoms: inattention, hyperactivity and impulsivity.¹⁰

Inattention

Inattention is not commonly a symptom that patients report as their presenting problem, as they often develop strategies to reduce or overcome the resultant impairment in their daily functioning.²⁵ Recognition of this symptom is usually poor, and it is usually recognised – if at all – by partners or family members rather than the patient.²

Adults with ADHD are no longer in school, so a common protective strategy is avoiding situations that require sustained attention in order to avoid inducing stress. Inattention may present as neglect, poor time management, poor concentration, and difficulties with motivation and arousal (difficulty starting, completing, or switching tasks).²⁹

Hyperactivity

Hyperactivity presents differently in adults as opposed to children. Symptoms of hyperactivity without inattention are less common. Instead of excessive running and climbing, behavioural hyperactivity may translate into excessive or rapid thoughts, or a constant or chronic restlessness or agitation. Many adults transform this into purposeful behaviour, such as being constantly busy, talking excessively, choosing an active job, working two jobs, or working long hours. Constant movements (e.g. leg twitching, picking at hair and the inside of their mouth, teeth grinding) are also symptoms of chronic restlessness or hyperactivity in ADHD.²⁵

Impulsivity

Impulsivity can present not only in behaviour (e.g. difficulty waiting, low frustration tolerance, impatience), but also in cognition and emotional reactivity. Impulsive thinking may present as making decisions without all the required information, jumping to conclusions, and acting without thinking of the consequences. Impulsivity may also lead to poor inhibition of emotional reactions. Such behaviours can present as poor problem solving, speeding whilst driving, impulsively spending money, and interrupting conversations. They can cause difficulty in interpersonal relationships, in the workplace, and in the criminal justice system.²⁷

Other behavioural symptoms associated with ADHD

Feeling overwhelmed

Presentation often involves feeling overwhelmed by demands, tasks that involve working memory, general life pressures, relationship problems (both interpersonal and intimate), difficulties with stress management, or feeling that “things just aren’t right”.²⁵

It is common for adults with ADHD to present with a lack of focus, inattention, restlessness, stress and/or emotional sensitivity, difficulty setting goals and achieving them, disorganisation, and constant turmoil or patterns of crisis in their daily functioning.²⁹

Poor working memory

ADHD can cause difficulties with working memory, behaviourally shown by forgetting instructions; difficulty recalling information that was just read; forgetting or being late to appointments, meetings or social plans; and losing or misplacing items (e.g. wallet, keys etc). Problems with accessing working memory are common, which presents as difficulty or inconsistency recalling information or memories of events.²⁹

Difficulties with social relationships

An adult with ADHD may present with difficulties in their social relationships, and may have poor personal insight into the underlying cause.²⁹ They may talk excessively, interrupt conversations, or display interpersonal impulsivity; this results in frustration and annoyance in the other party.³⁰

Sleep problems and arousal

It is now recognised that individuals with ADHD may have chronic difficulties with sleep, particularly in getting to sleep, lethargy upon awakening, and maintaining alertness during the day despite adequate hours of sleep. Feeling lethargic in the morning and late afternoon is common, as is a tendency to consume stimulants (e.g. nicotine, caffeine, sugar) to combat the lethargy. Important clinical features include difficulty regulating sleep and arousal, which some individuals may self-medicate with drugs and/or alcohol.³¹

Mood regulation

Affective lability or emotional dysregulation, a common symptom experienced by children with ADHD, can persist into adulthood. In fact, as many as 20–30% of adult ADHD cases are accompanied with reports of mood disturbances,²⁰ including low mood or dysphoria and feelings of overexcitement. Mood disturbances can be autonomous, or can occur in response to environmental stimuli.²⁹

Presentation can often include contact with the criminal justice system, substance use disorders, and significant difficulty in interpersonal relationships and personal finances. At times, rapid speech, irritability, agitation, and flightiness of thoughts and behaviours may be apparent; these symptom patterns are distinguishable from hypomania, in which patterns last for a significantly longer period with inappropriate affect and displays of heightened mood.²⁵ Adults with ADHD will tend to experience rapidly changing moods.²¹

Feelings of dysphoria in adult ADHD often appear as discontent or boredom, rather than clinical depression or anhedonia. However, clinical depression can be comorbid with ADHD.^25,27

Anger management

Affective lability is also congruent with difficulty controlling anger. Anger outbursts are often excessive and explosive, but individuals usually calm down relatively quickly between outbursts. Some individuals may ‘hyperfocus’ on their anger (due to the dopaminergic release) and have difficulty ‘letting go’, thus maintaining the anger episode. Some individuals with ADHD are chronically irritable, frightened when they lose control, and have difficulty understanding and making assessments of their outbursts.²⁵

Anxiety

The physiological agitation or restlessness that is so common with adult ADHD, when coupled with worry or fear cognitions, presents as an anxiety disorder. In addition, working memory overload and difficulty managing and organising daily routines and tasks can lead to feelings of anxiety and panic.²⁵ This vulnerability to the development of an anxiety disorder is shown in prevalence rates. Research shows that 20–30% of adults with ADHD are diagnosed with comorbid anxiety disorders such as generalised anxiety disorder (GAD), obsessive compulsive disorder (OCD) or post-traumatic stress disorder (PTSD).²⁰ All adults presenting with difficulty managing stress and anxiety, and who also exhibit impulsivity and inattention, should be screened for ADHD.

Substance abuse

It has been identified that a significant overlap exists between adults with ADHD and substance abuse, with comorbidity prevalence rates estimated between 15% and 40%.^20,32 The exact nature of this overlap requires further investigation, although the literature indicates this connection may be mediated by conduct disorder.^33,34 It has been indicated that ADHD is a strong risk factor for the development of substance use disorders.³² Adults with ADHD who use substances are more likely to develop a substance use disorder.³⁵ It has even been suggested that the combination of ADHD and substance use disorder actually increases the severity of both disorders.³⁶ The prevalence of ADHD within substance use disorders is indicated to be anywhere from 11% to 50%.³⁷ Therefore, all treatment seekers for drug and/or alcohol problems that display inattention and impulsivity should be screened for ADHD.

Problem gambling

Research shows that up to 1 in 3 problem gamblers meet the criteria for ADHD. Evidence suggests that, in certain individuals, neurological dysfunction causing impulsivity and difficulty sustaining attention is a precursor to the development of problem gambling. Individuals with comorbid ADHD and problem gambling are likely to have significantly more difficulty controlling gambling urges, due to high impulsivity and difficulty with response inhibition. In addition, gambling provides immediate reward and reinforcement, which acts as a relief or escape from perceived negative mood states (e.g. chronic boredom, low self-esteem, low mood, anxiety).³⁸

Clinical History

Approximately 75% of adults with ADHD present to front-line health professionals with problems that masquerade as other disorders, commonly resulting in the diagnosis of ADHD being missed or deemed irrelevant.^10,20

Identifying ADHD symptoms

To determine whether or not a patient is experiencing adult ADHD, symptom history should be assessed. A number of self-rating scales now exist for assessing symptom histories in adults with ADHD.¹⁰ However, it may also be necessary to obtain information from sources other than the patient, including school reports cards¹⁰ and interviews with the patient’s parents, or other relatives or long-term friends who may have witnessed the patient’s behaviour as a child.² At least some symptoms of ADHD must have been experienced during childhood for the condition to be diagnosed in an adult.¹⁰

It is also necessary to assess the degree of functional impairment arising from ADHD symptoms in various settings, such as the patient’s work, home and social life.¹⁰ Adult ADHD symptoms may be most apparent at work, as opposed to at school for children.² However, as with diagnosing the condition in childhood, functional impairment must occur in at least two different environments and impair functioning to a clinically significant degree for a diagnosis of ADHD to be made. The symptoms must also occur independently of the symptoms of other developmental (e.g. schizophrenia) and mood (e.g. anxiety disorder) disorders.¹⁰

Development history

The patient’s developmental history, including prenatal, childhood and educational history, should be taken. Prenatal history should investigate:¹⁰

• Maternal substance use;
• Pregnancy complications, including diabetes and preeclampsia;
• Complications of childbirth, including cord around the neck, breech delivery and lack of oxygen.

Childhood behaviour and experiences

Childhood history should investigate:¹⁰

• Serious trauma requiring hospitalisation;
• Verbal, physical and emotional abuse;
• Exposure to violence or other serious emotional trauma;
• Loss of consciousness.

Educational history

Educational history should investigate:¹⁰

• Academic achievement, including grades throughout primary and secondary school, consistency of achievement, teachers’ comments, repeating a grade, dropping out, and tertiary education;
• Disciplinary misconduct, including suspension or expulsion;
• History of learning disability, special difficulty with reading, writing or maths, or learning assistance.

Family psychiatric history

The patient and their family’s psychiatric history should also be investigated. Practitioners should enquire about a history of psychiatric conditions including:¹⁰

• ADHD;
• Depression;
• Anxiety;
• Psychosis;
• Tics;
• Substance abuse;
• Learning disability;
• Behavioural problems;
• Suicidal or self-harming behaviour.

Red flags

Other “red flags” that should raise suspicion of ADHD in adult patients include:⁴⁸

• A history of poor educational achievement, including failure to meet educational goals;
• Poor occupational functioning or frequent changes in employment;
• Workers’ compensation claims;
• Poor driving performance;
• Accidental injuries or risk-taking;
• Poor satisfaction with interpersonal relationships;
• Chronic credit or money management problems;
• Teen pregnancy and sexually transmitted diseases;
• Substance dependence and abuse disorders;
• Trouble organising a household or raising children;
• Poor emotional self-control;
• Depression.

It may also be useful to ask patients about the following symptoms, commonly experienced by adult ADHD patients:⁴⁸

1. Easily distracted by extraneous stimuli;
2. Impulsive decision making;
3. Difficulty stopping activities or behaviours when appropriate;
4. Often starting projects or tasks without reading or listening to directions or instructions carefully;
5. Poor follow-through on promises or commitments made to other people;
6. Trouble completing tasks in the right order;
7. Likely to drive a car much faster than other people do. Or if they do not drive, an equivalent behaviour is difficulty engaging in leisure activities or doing fun things quietly;
8. Difficulty paying attention to tasks and leisure activities;
9. Difficulty organising tasks and activities.

This information will be collected for educational purposes; however, it will remain anonymous.

Clinical Examination

Physical examination and psychological testing should be performed to rule out differential diagnoses and assess the presence or absence of comorbidities, health problems arising as consequences of ADHD, and contraindications to treatment. The patient’s weight should also be taken as this may change with treatment.¹⁰

Medical conditions that can mimic the symptoms of ADHD include, but are not limited to:

• Past acquired brain injury (e.g. serious head injury);¹⁰
• Sleep disorders;¹⁹
• Seizures;¹⁰
• Some endocrine disorders (e.g. hypothyroidism hyperthyroidism).¹⁰

Health problems which might arise as a result of ADHD include:¹⁰

• Substance abuse;
• Smoking;
• Poor nutrition;
• Fractures;
• Poor sleep hygiene, that is behavioural and environmental factors which may interfere with sleep.

Treatment is contraindicated in patients with hypertension and glaucoma.¹⁰

Diagnosing ADHD

Diagnosing ADHD in an adult can be difficult, because patients will typically not recognise the symptoms of ADHD. Most will simply feel unable to function in a way that allows them to accomplish tasks in everyday life. While general practitioners and other health professionals play an important role in recognising the symptoms of ADHD, performing preliminary assessments, and referring patients, diagnosis must be made by a specialist with expertise in attention deficit.²

Assessing symptoms

The diagnosis of ADHD in adults is based on similar criteria to childhood ADHD. Diagnosis usually begins with an assessment of current symptoms the patient has experienced in the past six months. This assessment is typically carried out using the DSM-IV criteria, which categorise symptoms as those of inattention or hyper-activity/impulsivity (discussed above). These criteria allow for diagnoses of three different types of ADHD:¹⁰

1. ADHD characterised predominately by inattention;
2. ADHD characterised predominately by hyperactivity/impulsivity (relatively rare in adults); and
3. ADHD with combined inattention and hyperactivity symptoms.

According to these criteria, patients should be asked to rate how often they have experienced various symptoms of ADHD, using the rating scale: 0 – never or not at all; 1 – sometimes or somewhat; 2 – often or pretty much; 3 – very often or very much. In order for a diagnosis of ADHD-inattentive or hyperactive to be made, the patient must have rated the frequency of at least six (three for patients over 50 years) of the inattention or hyperactivity symptoms as occurring “often” or “very often” in the past six months. In order for a combined ADHD diagnosis, the patient must rate at least six items on both of the scales as occurring “often” or “very often”.¹⁰

The symptoms are:¹⁰

Inattention

• Not paying close attention and making careless mistakes;
• Finding it difficult to pay attention;
• Finding it difficult to following verbal instructions;
• Not finishing tasks;
• Disorganisation;
• Avoiding doing things that require a lot of concentration;
• Misplacing things;
• Being easily distracted;
• Being forgetful.

Hyperactivity/impulsivity

• Fidgeting;
• Finding it difficult to sitting still;
• Being restless and jittery;
• Having trouble doing things quietly;
• Being always “on the go”;
• Talking too much;
• Acting before thinking things through;
• Getting frustrated when having to wait;
• Interrupting.

Validated screening instruments

There are a number of brief screening instruments that consist of sound psychometric properties:

• Conners’ Adult ADHD Rating Scales (CAARS);³⁹
• Brown Attention Deficit Disorder Scale (BADDS);⁴⁰
• Adult ADHD Self-Report Scale (ASRS): This 18-item self-report scale reflects the DSM-IV emphasis on symptoms, is widely used, and has been validated in the National Comorbidity Replication Survey.⁴¹ Subsequently, a six-item ASRS screen has been shown to out-perform the full version;⁴²
• Barkley Adult ADHD Quick Screen, based on the DSM-IV checklist for ADHD symptoms;²⁷
• Jasper/Goldberg Adult ADHD Screening Examination.⁴³

It may also be useful to have someone who knows the patient well enough to be aware of their behavioural patterns (e.g. someone they live with or spend considerable time with) complete the screening instrument.¹⁰

Differential diagnosis: Distinguishing adult ADHD from other conditions

Co-morbid psychiatric conditions

Accurately diagnosing ADHD can be difficult, and one factor complicating the diagnosis is the high prevalence of co-morbid psychiatric disorders in adult ADHD patients. Co-morbid psychological conditions (e.g. depression, anxiety, substance abuse disorders) are experienced by up to 90% of adult ADHD sufferers and present a major challenge to accurately diagnosing the condition.²⁸ Their risk of substance use disorders is increased by 4–5 times,^22,23 of developing an anxiety related disorder by 2–4 times, and of mood disorders by 2–6 times.^23,24 The majority of adult patients present with no prior knowledge of ADHD or the significant impact it may have on their daily functioning.² This may mean that ADHD is missed as a potential differential diagnosis.

Front-line health practitioners must therefore be cognisant of the high rate of co-morbidities between adult ADHD and other psychological conditions, so that they can appropriately institute screening and referral. While ADHD affects the quality of life of adult sufferers and many are aware that they have difficulty functioning normally, few adults recognise their symptoms stem from ADHD. Most patients who receive a diagnosis of ADHD do so after presenting with a co-morbid psychological condition.⁴⁶

Screening patients presenting with psychological complaints for ADHD

All patients presenting with psychological complaints should be screened for ADHD.⁴⁶ Evidence suggests the diagnosis of ADHD is often missed in these patients. For example, an American survey reported that the majority of cases who met the criteria for ADHD had not received treatment for ADHD, although many had received treatment for other psychological conditions.⁴⁷

As the study and recognition of adult ADHD is still a relatively new area, doctors have limited resources and references to use in the diagnosis of this condition. Differentiating it from other disorders that may have similar symptoms can therefore be challenging. Standard diagnostic criteria for ADHD tend to be based on the childhood form of the disorder and some of the specific behaviours commonly listed as symptoms – such as ‘climbs excessively’ – are irrelevant to adulthood.⁴⁸

A useful tool for recognising ADHD in adults is the acronym S.C.R.I.P.T, which means being alert to the possibility of ADHD in adults who exhibit problems with:⁴⁸

• Self-Control;
• Responsibilities and restlessness;
• Impulse-control;
• Persistence toward tasks and goals;
• Time management and organisation.

Specific Investigations

Electronic testing and neuropsychological tests may be performed to improve the practitioner’s overall picture of the patient’s condition; however, they have limited diagnostic value when used alone.¹⁰

Prognosis

30-70% of children with ADHD will continue to have troublesome symptoms of inattention or impulsivity as adults.² Adult and childhood ADHD appear to share a common neuropathology, and demonstrate similar responses to treatment.⁵ A meta-analysis of nine methodologically sound studies of stimulant therapy in adults showed 57% and 58% response rate to treatment respectively for methylphenidate and dextro-amphetamine.¹⁰

Studies have indicated that people diagnosed with ADHD tend to achieve poorer results in school, are less likely to graduate from high school or university, and are less likely to continue postgraduate study. Accordingly, ADHD is associated with lower employment rates and lower income for the individual which manifests on a national scale as loss of workplace productivity.²¹

References

1. Froehlich TE, Lanphear BP, Epstein JN, et al. Prevalence, recognition, and treatment of attention-deficit/hyperactivity disorder in a national sample of US children. Arch Pediatr Adolesc Med.2007; 161(9): 857-64. [Abstract | Full text]
2. National Institute of Mental Health (NIMH). Attention deficit hyperactivity disorder (ADHD): NIH Publication No 3572 [online]. Bethesda, MD: National Institutes of Health, US Departmnet of Health and Human Services; 3 April 2008 [cited 24 December 2008]. Available from: URL link
3. Royal Australasian College of Physicians, Paediatrics & Child Health Division. Medication management for attention deficit hyperactivity disorder: A brief guide for parents and non health professionals [online]. Auckland, NZ: Kidshealth; 10 July 2006 [cited 24 December 2008]. Available from: URL link
4. Attention deficit and hyperkinetic disorders in children and young people: A national clinical guidline [online]. Edinburgh: Scottish Intercollegiate Guidelines Network; 29 June 2001 [cited 24 December 2008]. Available from: URL link
5. NSW Health Pharmaceutical Services Branch. Criteria for diagnosis and management of attention deficit hyperactivity disorder in children and adolescents [online]. North Sydney, NSW: NSW Health; 1 February 2008 [cited 24 December 2008]. Available from: URL link
6. Adler LA, Chua HC. Management of ADHD in adults. J Clin Psychiatry. 2002; 63(Suppl 12): 29-35. [Abstract]
7. Kessler RC, Adler L, Barkley R, et al. The prevalence and correlates of adult ADHD in the United States: Results from the National Comorbidity Survey Replication. Am J Psychiatry.2006; 163(4): 716-23. [Abstract | Full text]
8. Pink B. 2008 Yearbook Australia. Canberra, ACT: Australian Bureau of Statistics; 23 January 2009 [cited 21 September 2009]. Available from: URL link
9. Salmelainen P. Trends in the prescribing of stimulant medication for the treatment of attention deficit hyperactivity disorder in adults in NSW. NSW Public Health Bulletin Supplement. 2004; 15(Suppl 3): 5. [Abstract| Full text]
10. Weiss M, Murray C. Assessment and management of attention-deficit hyperactivity disorder in adults. CMAJ. 2003; 168(6): 715-22. [Abstract| Full text]
11. Wallis D, Russell HF, Muenke M. Review: Genetics of attention deficit/hyperactivity disorder. J Pediatr Psychol. 2008; 33(10): 1085-99. [Abstract]
12. Larsson H, Lichtenstein P, Larsson JO. Genetic contributions to the development of ADHD subtypes from childhood to adolescence. J Am Acad Child Adolesc Psychiatry. 2006; 45(8): 973-81. [Abstract]
13. Gerring JP, Brady KD, Chen A, et al. Premorbid prevalence of ADHD and development of secondary ADHD after closed head injury. J Am Acad Child Adolesc Psychiatry. 1998; 37(6): 647-54. [Abstract]
14. Daley D. Attention deficit hyperactivity disorder: A review of the essential facts. Child Care Health Dev. 2006; 32(2): 193-204. [Abstract| Full text]
15. Sowell ER, Thompson PM, Welcome SE, et al. Cortical abnormalities in children and adolescents with attention-deficit hyperactivity disorder. Lancet. 2003; 362: 1699-707. [Abstract]
16. Swain A, Soutter V, Loblay R, Truswell AS. Salicylates, oligoantigenic diets and behaviour. Lancet. 1985; 2: 41-2.
17. Konofal E, Lecendreux M, Arnulf I, Mouren M. Iron deficiency in children with attention-deficit/hyperactivity disorder. Arch Pediatr Adolesc Med. 2004; 158(12): 1113-5. [Abstract| Full text]
18. Lamberg L. ADHD often undiagnosed in adults: Appropriate treatment may benefit work, family, social life. 2003; 290(12): 1565-7. [Abstract]
19. Willcutt EG, Doyle AE, Nigg JT, et al. Validity of the executive function theory of attention-deficit/hyperactivity disorder: A meta-analytic review. Biol Psychiatry. 2005; 57(11): 1336-46. [Abstract]
20. Goossensen MA, van de Glind G, Carpentier PJ, et al. An intervention program for ADHD in patients with substance use disorders: Preliminary results of a field trial. J Subst Abuse Treat. 2006; 30(3): 253-9. [Abstract]
21. Biederman J, Faraone SV. The effects of attention-deficit/hyperactivity disorder on employment and household income. MedGenMed. 2006; 8(3):12. [Abstract| Full text]
22. Weiss G, Hechtman L, Milroy T, Perlman T. Psychiatric status of hyperactives as adults: A controlled prospective 15-year follow-up of 63 hyperactive children.J Am Acad Child Psychiatry. 1985;24(2):211-20. [Abstract]
23. Biederman J, Faraone SV, Spencer T, et al. Patterns of psychiatric comorbidity, cognition, and psychosocial functioning in adults with attention deficit hyperactivity disorder. Am J Psychiatry. 1993; 150(12): 1792-8. [Abstract]
24. Biederman J, Newcorn J, Sprich S. Comorbidity of attention deficit hyperactivity disorder with conduct, depressive, anxiety, and other disorders. Am J Psychiatry. 1991; 148(5): 564-77. [Abstract]
25. Resnick RJ. The Hidden Disorder: The Clinician’s Guide to ADHD in Adults. Washington DC: American Psychological Association; 2000. [Book]
26. Brown TE, McMullen WJ Jr. Attention deficit disorders and sleep/arousal disturbance. Ann NY Acad Sci. 2001; 931(1): 271-86. [Abstract]
27. Barkley RA. Attention-Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment (2nd edition). New York: Guilford Press; 1998. [Book]
28. Togrerson T, Gjervan B, Rasmussen K. Treatment of adult ADHD: Is current knowledge useful to clinicians? Neuropsychiatr Dis Treat. 2008;4(1):177-86. [Abstract| Full text]
29. Adler LA. Clinical presentations of adult patients with ADHD. J Clin Psychiatry. 2004; 65(Suppl 3): 8-11. [Abstract]
30. Murphy K, Barkley RA. Attention deficit hyperactivity disorder in adults: Comorbidities and adaptive impairments. Compr Psychiatry. 1996;37(6): 393-401. [Abstract]
31. Brown TE, McMullen WJ Jr. Attention deficit disorders and sleep/arousal disturbance. Ann NY Acad Sci. 2001; 931(1): 271-86. [Abstract]
32. Wilens TE. Attention deficit hyperactivity disorder and substance use disorders. Am J Psychiatry. 2006; 163(12): 2059-63. [Full text]
33. Costello EJ. Psychiatric predictors of adolescent and young adult drug use and abuse: What have we learned? Drug Alcohol Depend. 2007;88(Suppl 1):S97-9. [Abstract]
34. Flory K, Lynam DR. The relation between attention deficit hyperactivity disorder and substance use: What role does conduct disorder play? Clin Child Fam Psychol Rev. 2003; 6(1): 1-16. [Abstract]
35. Davids E, von Bünau U, Specka M, et al. History of attention-deficit hyperactivity disorder symptoms and opioid dependence: A controlled study.Prog Neuropsychopharmacol Biol Psychiatry. 2005; 29(2): 291-6. [Abstract]
36. Levin FR, Evans SM, McDowell DM, et al. Buproprion treatment for cocaine abuse and adult attention-deficit/hyperactivity disorder. J Addict Dis. 2002; 21(2): 1-16. [Abstract]
37. Kalbag AS, Levin FR. Adult ADHD and substance abuse: diagnostic and treatment issues. Subst Use Misuse. 2005; 40(13-14): 1955-81, 2043-8. [Abstract]
38. Blaszczynski A, Nower L. A pathways model of problem and pathological gambling. Addiction. 2002; 97(5): 487-99. [Abstract]
39. Conners CK, Erhardt D, Sparrow EP. Conners’ Adult ADHD Rating Scales, Technical Manual. New York: Multi-Health Systems; 1999. [Book]
40. Brown TE. Brown Attention-Deficit Disorder Scales. San Antonio: Harcourt Brace and Company; 1996. [Book]
41. Adler L, Kessler R, Spencer T. Adult ADHD Self-Report Scales (ASRS) [online]. Havard School of Medicine; 7 January 2004. [cited 21 September 2009]. Available from: URL link
42. Kessler RC, Adler L, Ames M, et al. The World Health Organization adult ADHD self-report scale (ASRS): Ashort screening scale for use in the general population. Psychol Med.2005; 35(2): 245-56. [Abstract]
43. Jasper L, Goldberg I. Jasper/Goldberg Adult ADD/ADHD Screening Quiz [online]. Psych Central; 24 September 2007 [cited 21 September 2009]. Available from: URL link
44. MTA Cooperative Group. A 14-month randomized clinical trial of treatment strategies for attention-deficit/hyperactivity disorder. Arch Gen Psychiatry. 1999; 56(12): 1073-86. [Abstract| Full text]
45. ADDults with ADHD (NSW) Inc. About us [online]. 2007 [cited 22 September 2009]. Available from: URL link
46. Barkley RA, Newcorn J. Assessing adults with ADHD and comorbidities. Prim Care Companion J Clin Psychiatry. 2009;11(1):25. [Full text]
47. Kessler R, Adler L, Barkely R, et al. The prevalence and correlates of adult ADHD in the US: Results from the National Comorbidity Survey Replication. Am J Psychiatry. 2006;163(4):716-22. [Abstract| Full text]
48. Barkley RA. Attention Deficit Hyperactivity Disorder in Adults: The latest assessment and treatment strategies. Sudbury, MA: Jones and Bartlett Publishers; 2010. [Book]