Attention-Deficit-Hyperactivity Disorder
last authored: Aug 2011, David LaPierre
last reviewed:
Introduction
Attention-Deficit-Hyperactivity Disorder (ADHD), also known as ADD and previously minimal brain disorder, is a well-known, but also controversial disorder.
Prevalence varies amongst country, but is estimated as 6-12% worldwide. It is more common in males and in children, with prevalence falling with age. However, many people are concerned about overdiagnosis. "Rates" in North America are quite a bit higher than in the UK, mediated in part by different diagnostic criteria.
ADHD can be defined as a cluster of suggestive behaviour consistently observed in two or more settings causing significant dysfunction academically, behaviourally, and socially. Deficits are seen in:
- regulation of one's activity to the demands of the situation (hyperactivity)
- behavioural inhibition (impulsivity)
- sustained attention and resistance to distraction (inattention)
There are three subtypes - hyperactive/impulsive, inattentive, and combined.
People with ADHD can also have difficulty self-monitoring.
The Case of Alex R
Alex is a 7 year-old boy sent to his family doctor by the school with concerns about his behaviour. He has been very difficult to control, he is freqently found staring off and not paying attention, and his school work is poor.
- What questions do you ask as you consider a diagnosis of ADHD?
- How do you diagnose ADHD?
- What treatments, if any, do you consider?
Causes and Risk Factors
ADHD is thought to be the most common neurodevelopmental disorder of children and adults.
Specific causes are unknown, but family history is a strong risk factor. Concordance rate is 0.6-0.8 in identical twins, and children of adults with ADHD have a 20-25% risk of also having the disorder.
Other risk factors are believed to include:
- prenatal exposure to alcohol, smoking, and/or cocaine
- prematurity and low birth weight
- increased lead and heavy meal levels exposure
Environmental factors such as the following can exacerbate but does not cause ADHD.
- parental depression or bipolar disorder
- low socioeconomic status
Pathophysiology
There is no single deficit in ADHD; rather, there is an overall decrease in behavioural inhibition affecting four functions:
- prolongation and working memory
- self regulation of affect, motivation, and arousal
- internalization of speech
- reconstitution
Executive function: inability to plan adequately for future events: forward planning and response inhibition.
Imbalance of catecholamine and dopamine pathways.
anterior cingulate
Comorbidities
- anxiety disorders
- depression
- oppositional defiance disorder/conduct disorders
- learning disabilities
- enuresis
- encopresis
- substance abuse
Signs and Symptoms
Diagnosis is made by history, observation, rating scales, and with performance on tests, ie continuous process tasks (CPT).
Many clinicians will depend on three visits to make a diagnosis:
- how are you? send rating scales home for parent and teacher to fill out
- formal child testing
- discussion of plan of action
- history
- diagnostic criteria
- ratings scales
- physical exam
History
The teacher often first suggests something is the matter.
Begin by asking the child what they think.
Evaluate for anxiety symptoms
Ask parents:
- can he follow multistep commands?
- are there places your child can't go?
- how is the child in a quiet place such as church? in a stimulating place such as WalMart?
Developmental history
Family history: academic history, behaviour
Behaviour, academic, and social function must be evaluated.
- family/home evaluation
- school/teacher evalutation
- behaviour rating scales
- emotional lability
Functional inquiry should include:
- headaches
- abdominal pain
Diagnostic Criteria
In order for diagnosis to be made:
1) Six or more symptoms of either category below must be present for 6 months, maladaptive, and inconsistent with developmental level.
2) There must be clear evidence of functional impairment.
3) Some symptoms of impairment must be present prior to age 7.
4) There needs to be impairment in 2 or more settings, including social, academic, and occupation.
5) Not better accounted for by another diagnosis.
As mentioned, there are three subtypes that may be considered:
- hyperactive/impulsive (6/9 criteria)
- inattentive (6/9
- combined (6/9 in both)
Inattentive Symptoms
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Hyperactive/Impulsive Symptoms
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Ratings Scales
Rating scales are mainly to measure degree of dysfunction, NOT make a diagnosis. One of the commonly used tools is the SNAP-IV Rating Scale.
Physical Exam
Assess and track height and weight.
BP
ENT
chest
heart sounds
abdominal
tics
neuro
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Investigations should be guided by clinical suspicion, and could include:
- TSH (thyroid disease)
- CBC (anemia)
Diagnostic Imaging
Differential Diagnosis
Normal child
Normal child in new situation
Child under stress
Anxiety disorders
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Mood disorder
Psychotic disorder
Substance abuse
Medical disorders
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Medications
Allergies (very occasionally)
Mental retardation
Learning disability
Autism spectrum disorder (can co-exist with ADHD)
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Stimulants can improve symptoms caused by many of these conditions; response to medication should therefore not be used in the diagnosis.
Treatments
There is evidence that medications are better than behaviour management, though a combination of the two is best.
Behaviour Management
Educate family regarding what it means to have ADHD and how to maximize treatment response.
Behaviour modification for patient and family can be helpful regarding triggering or stressful situations. Warn parents and teachers not to say "did you take your pill this morning?" It is important to ensure that there is understanding that the medication does not control them.
Emotional management for patient and family is necessary to protect child's self-esteem and to release family from guilt and blame.
Academic accommodations may be required, especially as medications are optimized.
Medications
Commonly used stimulants include methylphenidate and dextroamphetamine. Atmoxetine (Strattera) is a stimulant with delayed onset, lessening the potential for abuse. Second-line agents include the TCAs clonidine or desipramine.
Contraindications include MAOI use, psychosis, glaucoma, cardiac conditions, and liver disorders.
When considering the use of medication, the following steps may be helpful:
- counselling: discuss benefits and risks, follow-up, and the shift from short- to long-acting
- titration: weekly monitoring of behaviours, side effects, and dosing modifications
- maintenance: monitor function, side effects, adherence, changes in activities, and maintenance of growth
- termination: once decided upon
In order to confirm the utility of medication, use two dose-levels and a placebo, arranged by a pharmacy, along with ratings scales filled out by parents, teachers, and physicians. NEVER make a diagnosis based on response to medication.
Common side effects include:
- appetite suppression
- stomach ache and nausea
- weight loss (greatest first 6 months; follow weight and encourage increased intake)
- decreased growth: first of weight, then height.
- initial insomnia (inquire into beforehand)
- tics
- zombie-like behaviour (less common; suggests the wrong dose or the wrong drug)
Sudden death risks have been often discussed but do not appear to be of concern if cardiac history, physical exam, family history are not revealing.
Consequences and Course
There are three general outcome groups.
30% function well.
50-60% have some ongoing difficulty into adulthood.
10-15% have very poor function. This is predicted if conduct disorder is also present, or if there is low IQ or parental pathology.
ADHD increases risk for:
- family/school disruption
- unhappiness
- cigarette smoking
- substance abuse
- higher accident/injury rate
- difficulties with peer interactions
- early death
Resources and References
Topic Development
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