Attention Deficit Hyperactivity Disorder
From Ask Dr Wiki
This article was prepared by Margo Benjamin, M.D., faculty member of Weill Cornell Medical Center and New York Presbyterian Hospital
Contents |
Key Criteria For Diagnosis of ADHD
Children with ADHD typically present with a triad of symptoms:
- Hyperactive
- Impulsive
- Inattentive
The DSM-IV-TR defines hyperactive as "fidgets/squirms/leaves seat/talks excessively" and the classic description is that the child appears "as if driven by a motor". Impulsivity can manifest in a variety of ways - the most typical are blurting out answers in the classroom setting, having difficulty waiting during turn taking activities and intrusive with others during conversations. The term "inattentive" refers to the inability to pay close attention to details, difficulty following instructions, and difficulty organizing tasks and activities.
Symptoms begin prior to age 7 years, last at least six months and occur in two or more different environments (ex: home and school). The symptoms must impair functioning in academic, social or occupational activities and must be excessive for the developmental level of the child to fit criteria for making the diagnosis.
Three subtypes of ADHD are described in the literature.
- Predominantly Hyperactive-Impulsive Type
- Predominantly Inattentive Type
- Combined Type
Prevalence of ADHD is 3-5%; up to 10% has been reported, depending on the source. There is a gender preponderance of males (3M:1F) in the hyperactive subtype.
Assessment of ADHD
As part of the assessment of a child who presents with ADHD symptoms, it is important to rule out other possible causes such as head trauma, lead poisoning, neurological disorders and medication side effects. The differential diagnosis also includes mood disorders, pica, thyroid dysfunction, lyme disease, substance use disorders, pervasive developmental disorders, mental retardation, fetal alcohol syndrome and primary sleep disorders. The physical examination should include baseline height and weight, hearing and vision screenings and a baseline heart rate, blood pressure and 12 lead EKG.
Laboratory Data
Baseline bloodwork including cbc, complete metabolic profile, TSH (or complete TFT's if child is needle phobic and there is a family history of thyroid dysfunction), lead level, and phenytoin/phenobarbitol/theophylline levels in children taking these medications.
Rating Scales
Rating Scales used in the assessment of children with ADHD symptoms include the Diagnostic Interview Schedule for Children, Child Behavior Checklist Parent and Teacher versions, Conner's Parent and Teacher Scales, Social Skills Rating System, and The Behavior Rating Inventory of Executive Functioning.
Neuropsychological Testing
Neuropsychological testing is helpful in delineating cognitive strengths and weaknesses. A typical battery includes measures of intelligence (WISC-IV), academic achievement, tests of executive function and tests of memory, attention and concentration.
Neuroimaging Studies
Although neuroimaging is not used as a diagnostic tool, differences have been noted in the brains of children diagnosed with ADHD compared to those without the diagnosis.
MRI SCAN
- Decreased anterior frontal lobes
- Decreased basal ganglia and cerebeller vermis
PET SCAN
- Decreased insular and hippocampal areas
It is worth noting that a low concentration of norepinephrine in the right dorsal and orbital regions of the prefrontal cortex are thought to account for many of the symptoms of ADHD. There is also some speculation that certain in utero variables increase the risk of later development of ADHD including exposure to alcohol and tobacco, and third trimester complications - toxemia, eclampsia, postmaturity and extended labor.
Comorbid Diagnoses
Attention Deficit Hyperactivity Disorder has a tendency to co-exist with other psychiatric diagnoses. [Oppositional Defiant Disorder]/[Conduct Disorder], and learning or language problems are the most common comorbid diagnoses with ADHD 45 -84% of children and adolescents with ADHD will have symptoms of oppositional defiant disorder or conduct disorder. Oppositional Defiant Disorder is defined as having four or more symptoms for a minimum of six months which impairs social/occupational functioning (see DSM IV TR for details). The most common symptoms seen with ODD are: often loses tempter, argues with adults, refuses to comply with rules, deliberatly annoys others. In Conduct Disorder the symptoms last at least 12 months and include aggression to people or animals, destruction of property, deceitfulness and/or theft, and serious violation of rules. Up to 35% of patients with ADHD have a coexisting learning or language (expressive and/or receptive) problem.
Other comorbid diagnoses with ADHD are anxiety disorder (27 - 30 %), depression (15 - 30%) and tic disorders. Tic disorders in the general population have a prevalence rate of 21%. Tourettes + ADHD has a prevalence rate of 21 - 54%. In the [MTA Study (1996) the combination of ADHD + all tic disorders occurred in 10% of the 579 children studied.
There is controversy regarding the comorbidity of ADHD with bipolar disorder. The controversy lies both in the identification of bipolar disorder in children and the overlap of ADHD and bipolar symptoms - irritability, mood lability, impulsivity, hyperactivity and dysomnia.
In addition to the above comorbidities it is important to note that ADHD can effect children/adolescents and the adults they become on many levels, academically and socially - and can contribute to injuries, substance abuse risk, motor vehicle accidents, legal problems, occupational and vocational difficulties.
Evidence for Genetic Factors
Family aggregation studies, adoption studies and twin studies have shown some evidence of a genetic vulnerability for increased risk of the development of ADHD. For example, in twin studies monozygotic twins showed a 61% - 81% concordance, while dizygotic twins showed a 0% - 29% concordance rate.
Treatment of ADHD
The treatment of ADHD involves behavioral treatment, parental counseling and medications. In terms of behavior, ADHD effects executive functioning including verbal and nonverbal working memory, emotion regulation and planning. Treatment is therefore focused on improving these, as well as decreasing hyperactivity and distractibility.
In 1996 the National Institute of Mental Health (NIMH) conducted a collaboative multisite multimodal treatment study of children with ADHD (the MTA Study). Five hundred seventy nine children whose ages ranged from 7 - 9.9 years with ADHD (combined type) were randomly assigned to one of four tratment groups for fourteen months in a double blind study.
- Medication management
- Intensive behavior modification
- Both medication and behavioral modification
- Community treatment (control group) - usually medication alone
Outcomes were assessed in multiple domains and included the core symptoms of ADHD co-occuring problems in social skills, parent-child relations, oppositional defiant behavior, anxiety and academic achievement. All four groups improved over time. Children treated with either Medication alone or with therapy had a better outcome in regards to the core symptoms of ADHD, compared to those treated with behavioral intervention alone and the community treatment control group. The group that received combined treatment showed greater benefits than the community treatment group across other domains such as disruptive behavior, social skills and parent-child relationship. Unlike studies done with antidepressants which have shown that the best outcomes occur with the combination of therapy and medication, it appears that the groups on medication with and without therapy did equally as well.
Stimulant Medications
The most common FDA approved medications used for the treatment of ADHD are the stimulants. Stimulants are usually the first choice of treatment because of the 60+ years of clinical experience and therefore more is known about stimulant use in children with ADHD than any other medication. Overall, stimulants have a fast onset (generally within 30 minutes of administration), are easy to titrate and a positive response can be predicted essentially after the first dose.
Methylphenidate (Ritalin, Focalin, Methylin, Ritalin SR, Metadate ER, Metadate CD, Ritalin LA, Concerta, Focalin XR, Ritalin Patch) inhibits the reuptake of dopamine and norepinephrine through inhibition of the dopamine transporter system. Therefore an increased amount of dopamine and norepinephrine is available in the synaptic cleft. Most of these are 50:50 racemic mixtures of l and d threo methylphenidate, with the exception of focalin which is pure D threo (and twice as potent in terms of dosing). The long acting forms are either in a wax based (Metadate ER), methylcellulose base (Methylin ER) or beads with a bimodal delivery system. Concerta has a unique delivery system which is based on osmotic pressure.
The amphetamines (Dexadrine, Dextrostat, dexadrine spansules) diffuse into storage vessicles and cause the release of dopamine to the cytoplasm and blocks reuptake into the vessicle.
Mixed amphetamine salts include Adderall and Adderall XR. During the summer of 2005 case reports were disclosed which showed sudden cardiac death in 15 children being treated with Adderall products in the United Kingdom. The United States response was to include a warning on the label, while the Canadian response was to suspend marketing of the XR form of Adderall (Canada had never marketed the immediate release form). Canada reinstituted the XR marketing in August 2005 with revised package inserts reflecting safety concerns including sudden cardiac death. In November 2005 the United States added a boxed warning regarding the risk of increased suicidal ideation in children and adolescents taking Adderall products.
- common side effects of stimulant medications include rebound, insomnia, irritable mood, tics and decreased appetite which can lead to weight loss and decelerated growth in some children.
-Rebound is a phenomenon seen in some children on stimulants which refers to the increased hyperactivity and impulsivity that can occur after the medication is metabolized (the short acting stimulants last about four hours, the long acting forms vary but generally last 3-8 hours with the exception of Concerta which lasts up to 12 hours).
-Children on stimulant medications can have trouble sleeping, particularly those being dosed in the afternoon to cover the second half of the day and late afternoon (around homework time).
-Generally speaking it is believed that stimulants do not themselves cause tics, but rather they "uncover" tics that were already present but not noticeable prior to the stimulant trial.
-Children on stimulant medications should be closely monitored for appropriate growth pattern. Gastrointestinal upset (which usually leads to decreased appetite) after dosing can be minimized by administering the medication with food.
Nonstimulant Medications
Atomoxetine (Strattera) is a non stimulant medication that works by blocking the norepinephrine pump on the presynaptic membrane which increases the availability of intrasynaptic norepinephrine. The main side effect commonly associated with atomoxetine is gastrointestinal distress, which can interfere with appetite. The efficacy of this medication does not appear to be equal to the other medications available in my experience with it.
Antidepressant medications as a class, are used as "second line" treatment for the ADHD disorders. The two types used are buproprion and tricyclics (SSRI's are not used to treat ADHD). Buproprion (Wellbutrin, Wellbutrin SR and Wellbutrin XL) blocks the reuptake of norepinephrine and dopamine. Tricycylic antidepressants (Nortriptyline) work by inhibiting the reuptake of norepinephrine and serotonin. The major side effect/adverse reaction that can be seen with use of buproprion is seizures (has to be carefully monitored and is contraindicated in patients with known seizure disorders). Tricyclics although generally well tolerated can have significant side effect/adverse reactions. Most important to monitor are the cardiovascular side effect risks which include sudden cardiac death, arrythmias, and hypertension. Tricyclics side effect profile alsoincludes the anticholinergic symptoms associated with its use including dry mouth, sedation, dry eyes, blurred vision, urinary retention, constipation and cognitive dysfunction.
Antihypertensives used for the treatment of ADHD are clonidine (Catapress) and guanfacine (Tenex). Clonidine stimulates presynaptic alpha 2 adrenergic receptors in the brain stem which decreases plasma norepinephrine. Guanfacine stimulates alpha 2 autoreceptors to down regulate sympathomimetic outflow from the brain stem. An extended release form of this drug is pending. Prior to starting clonidine or guanfacine a baseline ECG, heart rate and blood pressure should be obtained. The BP and heart rate should be monitored closely during the titration of these medications, to reduce the risk of hypotensive symptoms (dizziness and presyncopal or syncopal events). These medications are particularly useful in children with ADHD and aggressivity, tics or insomnia. They are not recommended for children with known cardiac disease, those with family history of cardiac disease or depression.
In rare cases other medications are used to treat ADHD including atypical neuroleptics, modafinil (Provigil), MAOI inhibitors (selegiline) and cholinergic enhancing medications (Donazepil and Tacrine). The atypical neuroleptics work by influencing the dopamine system, modafinil exerts its effect via the hypothalamus-orexin system in mediating wakefulness and vigilance.
Behavioral Interventions
- Behavioral Modification
- Parental Counseling/Psychoeducation
- Individual psychotherapy
- Family Therapy
- Social skills Training
Behavioral modification using rewards such as "token economies" whereby a child can earn a "prize" each time he displays (or doesn't display) the targetted behavior. At the end of a week the smaller prize is traded in for a larger one. After being successful for a defined amount of time regarding a specified behavior, the plan can be revised to incorporate new target behaviors.
Parental counseling/psychoeducation is an important piece of the therapeutic treatment plan for a child with ADHD. Assisting parents with creating behavioral modification plans and teaching them other methods of helping their child reach their highest potential academically (with the school's support) are invaluable tools that can be imparted to parents.
The MTA study results indicated that individual psychotherapy although useful, is most efficacious when combined with a medication intervention.
Family therapy with ADHD children can help educate family members about the disorder amd facilitate effective ways of communicating behavioral expectations from the child.
Social Skills training is an effective therapeutic intervention for children with ADHD. In social skills groups, children learn "in vivo" appropriate ways of interacting with others which often times focuses on improving frustration tolerance and impulse control.
Adult ADHD Diagnosis And Treatment
The prevalence of ADHD in the adult population is 4-5%. Adult ADHD results from persistance of symptoms into adolescence and adulthood. Approximately 30 - 80% of children with the disorder carry it into adolescence, while up to 65% of children with ADHD carry it into their adult years. The criteria for diagnosing ADHD in adults is the same as it is for children. If the adult presenting with ADHD symptoms does not have a history of being diagnosed during childhood, it is important to try to ascertain the academic and family history and to rule out other psychopathology.
The treatment of ADHD in adults is the same as that for children with the disorder. Stimulants can be used, but be aware of the abuse potential. Although stimulants are frequently used, the FDA has approved only atomoxetine and D threo mehtylphenidate (Focalin) in adults. Unlike children and adolescents, the adult patient with ADHD is able to make significant gains with individual therapy. Also consider vocational evaluation, counseling or training for adults with ADHD.
References
American Academy of Child and Adolescent Psychiatry (2007). Practice parameter for the assessment and treatment of attention-deficit/hyperactivity disorder.
Barkley, Russell A. Attention Deficit Hyperactivity Disease - A Handbook for Diagnosis and Treatment 3rd Edition. New York: The Guilford Press 2006.
Martin, Andres MD, MPH, Bostic Jeff MD, EdD Child and Adolescent Psychiatric Clinics of North America Psychopharmacology. Pennsylvania: W.B.Saunders Co 2006.
Selowitz, Mark ADHD The Facts. New York; Oxford University press Inc. 2004.
Steiner, Hans, Editor Handbook of Mental Health Interventions in Children and Adolescents - An Integrated Development Approach. California: Jossey-Bas Publication; 2004.
Janicak, Philip G. M.D., Davis John M., M.D., Preskorn, Sheldon H., M.D., Ayd, Frank J. M.D. Principles and Practice of Psychopharmacotherapy, 3rd Ed. Pennsylvania: Lippincott Wiliams and Wilkens; 2001.
American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, Washington, DC, American Psychiatric Association, 2000.
