Attention deficit hyperactivity disorder Dr. Varunee Mekareeya, M.D., FRCPsychT Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders in childhood. At least half of children with ADHD have impairing symptoms persisting to their adolescence or adulthood. Three clusters of symptoms include inattention, hyperactivity and impulsivity. ADHD is predominantly a genetic disorder with environmental factors contributing a small role to the etiology of ADHD. Treatment of ADHD involves parent education, psychological interventions, educational intervention and medication therapy. Epidemiology The worldwide-pooled prevalence of ADHD is 5.29 percent. There is both geographical and local variability among studies. Children in North America appear to have a higher rate of ADHD than children in Africa. ADHD is diagnosed three to four times more commonly in boys than in girls. This difference between genders may reflect either a difference in susceptibility or that females are less likely to be diagnosed than males. Between 2 and 5 percent of adults have ADHD. Untreated adults with ADHD often have chaotic lifestyles. Etiology The specific causes of ADHD are not known. Many factors may contribute to, or exacerbate ADHD. They include genetic, executive function, diet and the social and physical environments. Many studies suggest that genes play a large role in about 75 percent of all cases. A large majority of ADHD cases may arise from a combination of various genes which include dopamine 4 and 5 receptor gene, dopamine transporter gene, dopamine beta-hydroxylase gene and serotonin transporter gene. Executive function deficits are met in 30-50 % of children and adolescents with ADHD. Groups with ADHD showed significant impairment on all executive function tasks. The strongest effects were on measures of response inhibition, vigilance, working memory, and planning. Studies suggest that environmental factors such as lead intoxication, cigarette smoking and alcohol use during pregnancy, premature birth and very low birth weight increase the risk of the child to develop ADHD. It is possible that certain food colourings act as a trigger for ADHD symptoms in subgroup of children who have a genetic vulnerability.
Researchs believe that relationships with caregivers have a profound effect on attentional and self-regulatory abilities and may exacerbate ADHD. Pathophysiology Research on children with ADHD has shown a general reduction of brain volume but with a proportionally greater reduction in the volume of the left-sided prefrontal cortex. These findings suggest that the core ADHD features may reflect frontal lobe dysfunction. A 2005 review of published studies suggest that four connected frontostriatal regions play a role in the pathophysiology of ADHD : The lateral prefrontal cortex, dorsal anterior cingurate cortex, caudate, and putamen. There is evidence that people with ADHD have abnormalities in the functioning of dopamine, adrenergic, serotoninergic and cholinergic or nicotinergic system. Clinical features The key behaviors of ADHD are inattention, hyperactivity and impulsivity. Children with ADHD must have these behaviors for 6 or more months. Their behaviors are more severe than other children of the same age. Children who have symptoms of inattention may: - Be easily distracted, miss details, forget things, and frequently switch from one activity to another - Have difficulty focusing on one thing - Become bored with a task after only a few minutes, unless they are doing something enjoyable - Have difficulty focusing attention on organizing and completing a task or learning something new - Have trouble completing or turning in homework assignments, often losing things (e.g., pencils, toys, assignments) needed to complete tasks or activities - Not seem to listen when spoken to - Daydream, become easily confused, and move slowly - Have difficulty processing information as quickly and accurately as others - Struggle to follow instructions. Children who have symptoms of hyperactivity may: - Fidget and squirm in their seats - Talk nonstop - Dash around, touching or playing with anything and everything in sight - Have trouble sitting still during dinner, school, and story time
- Be constantly in motion - Have difficulty doing quiet tasks or activities. Children who have symptoms of impulsivity may: - Be very 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 turns in games - Often interrupt conversations or others' activities. Some people with ADHD have difficulties with social skills, such as social interaction and forming and maintaining friendships. About half of children and adolescents with ADHD experience rejection by their peers. Adolescents with ADHD are more likely to have difficulty making and keeping friends due to impairments in processing verbal and nonverbal language. Associated features and disorders Associated features may include low frustration tolerance, temper outbursts, bossiness, stubbornness, mood lability, demoralization, dysphoria, rejection by peers and poor selfesteem. People with ADHD also have associated disorders. The combination of ADHD with other conditions can greatly complicate diagnosis and treatment. Some of the associated disorders are: - Oppositional defiant disorder and conduct disorder, which occur with ADHD at a rate of 50 percent and 20 percent respectively. About half of those with hyperactivity and ODD or CD develop antisocial personality disorder (ASPD) in adulthood. - Learning disorder. - Mood disorders (especially Bipolar disorder and Major depressive disorder). Boys diagnosed with combined ADHD subtype have been shown to be more likely suffer from a mood disorder. - Anxiety disorders, have been found to occur more commonly in people with ADHD. - Communication disorders. - Borderline personality disorder, which was according to a study on 120 female patients treated for BPD associated with ADHD in 70 percent of cases. - Obsessive-compulsive disorder.
Diagnosis - Substance use disorders. People with ADHD are at a significantly increase risk of developing substance-related problems. The most commonly misused substances are alcohol and cannabis. - Restless legs syndrome, is often due to iron deficiency anemia. - Sleep disorders such as obstructive sleep apnea syndrome. Insomnia is the most common sleep disorder found in ADHD children. Melatonin is sometimes used in children who have sleep onset insomnia. - Tourette s disorder. Among children who have tourette s disorder, many also have ADHD. The onset of the ADHD often precedes the onset of the Tourette s disorder. Most ADHD symptoms usually appear early in life, often between the ages of 3 and 6. ADHD is diagnosed via a psychiatric assessment of the person s childhood behavioural and cognitive development symptoms; this assessment includes ruling out other reasons for the symptoms. In North America, The DSM-IV criteria are often the basis for a diagnosis. Diagnostic criteria for Attention-Deficit/Hyperactivity Disorder A. Either (1) or (2): (1) Six (or more) of the following symptoms of inattention have persisted for at least 6 months to a degree that is maladaptive and inconsistent with the developmental level: Inattention (a) often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities (b) often has difficulty sustaining attention in tasks or play activities (c) often does not seem to listen when spoken to directly (d) often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions) (e) often has difficulty organizing tasks and activities (f) often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as schoolwork or homework)
(g) often loses things necessary for tasks or activities (e.g. toys, school assignments, pencils, books, or tools) (h) is often easily distracted by extraneous stimuli (i) if often forgetful in daily activities (2) Six (or more) of the following symptoms of hyperactivity-impulsivity have persisted for at least 6 months to a degree that is maladaptive and inconsistent with the developmental level: Hyperactivity (a) often fidgets with hands or feet or squirms in seat (b) often leaves seat in classroom or in other situations in which remaining seated is expected (c) often runs about or climbs excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective feelings of restlessness) (d) often has difficulty playing or engaging in leisure activities quietly (e) is often on the go or often acts as if driven by a motor (f) often talks excessively Impulsivity (a) often blurts out answers before questions have been completed (b) often has difficulty awaiting turn (c) often interrupts or intrudes on others (e.g., butts into conversations or games) B. Some hyperactivity-impulsive or inattentive symptoms that caused impairment were present before age 7 years. C. Some impairment from the symptoms is present in two or more settings (e.g., at school [or work] and at home). In the tenth edition of the International Statistical Classification of Diagnosis and Related Health Problems (ICD-10), the signs of ADHD are given the name hyperkinetic disorders (F 90). When a conduct disorder is present, the condition is referred to as hyperkinetic conduct disorder (F 90.1). Otherwise the disorder is classified as disturbance of activity and attention (F 90.0), other hyperkinetic disorders (F 90.8) or hyperkinetic disorder, unspecified (F 90.9). The latter is sometimes referred to as, hyperkinetic syndrome.
Differential Diagnosis Other psychiatric disorders that must be excluded from ADHD included : mental retardation, learning disorders, autistic disorder, oppositional defiant disorder, conduct disorder, adjustment disorder, depression, anxiety disorder and bipolar disorder. Medical conditions that must be excluded as causing the ADHD symptoms include : hypothyroidism, anemia, lead poisoning, chronic illness, hearing or vision impairment, substance abuse, medication side-effects, sleep disorders and child abuse. Treatment Treatments focus on reducing the symptoms of ADHD and improving functioning. Treatments include medication, various types of psychotherapy, education or training, or a combination of treatment. Medications Medications reduce hyperactivity and impulsivity and improve children s ability to focus, work, and learn. Medication also may improve physical coordination. The most common type of medication is called a stimulant which has a calming effect on children with ADHD. It controls the symptoms for as long as it is taken. Any child taking medications must be monitored closely and carefully by caregivers and doctors. Psychotherapy Different types of psychotherapy are used for ADHD. Behavioral therapy teaches a child how to monitor his or her own behavior. Another goal of behavioral therapy is learning to give oneself rewards of acting in a desired way. Parents and teachers also can give positive or negative feedback for certain behaviors. Therapists may teach children social skills, such as how to wait their turn, share toys, ask for help or respond to teasing; and how to respond appropriately to facial expressions of others. Prognosis In the United States, 37 percent of children with ADHD do not get a high school diploma even though many of them will receive special education services. Less than 5 percent of individuals with ADHD get a college degree compared to 28 percent of the general population aged 25 years and older.
ADHD and crime The police service and other agencies within criminal justice should recognize the importance of ADHD. Some robust statistics catch our attention: - People with ADHD are twice as likely to commit crime. - People with ADHD commit three times as many offences as those without the disorder. - People with ADHD are more susceptible to problematic drug use. - People with ADHD are more likely to attempt to take their own life. - People with ADHD are four times more likely to crash a road vehicle, seven times more likely to be at fault. Most states in USA use a graduated licensing system, in which young drivers learn about progressively more challenging driving situations. Parents should make sure that their teens, especially those with ADHD, understand and follow the rules of the road. Repeated driving practice under adult supervision is especially important for teens with ADHD. Reference 1. Attention Deficit Hyperactivity Disorder(ADHD). [Internet]. Available from: http:///www.nimh.nih.gov/health/publications/attention-dificit-hyperactivitydisorder/complete-index.shtml 2. Boon-yasidhi V. Attention Deficit Hyperactivity Disorder: Diagnosis and Management. J Psychiatr Assoc Thailand 2012; 57 Suppl 4: 373-386. 3. Attention deficit hyperactivity disorder. [Internet]. Available from: http://www.en.wikipedia.org/wiki/attention_deficit_hyperactivity_disorder 4. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4 th edition Text rev.(dsm-iv-tr). Washington, DC: American Psychiatric Association; 2000. p.87-93. 5. Hyperkinetic disorders. In: The ICD-10 classification of mental and behavioural disorders: clinical descriptions and diagnostic guidelines. Geneva, Switzerland: World Health Organization; 1992. p.262-266. 6. ADHD and crime generally. [Internet]. Available from: http://www.adhdand justice.co.uk/badge/adhd-and-crime-generally.aspx