Etiology of ADHD


Etiology of ADHD

Scientific research over the years has documented a number of solid finding about individuals with ADHD including the support for brain based differences and genetic components (Geid, Blumenthal, Molloy & Castellanos). Research using electroencephalogram (EEG) recordings demonstrated that people with ADHD have different electrical activity in their brains. These differences in EEG recordings patterns are associated with problems in sustaining attention and inhibiting responses, and the differences seem to lessen when stimulant medications are used. Blood flow to the brain was also studied; results suggested that individuals with ADHD have decreased blood flow in areas of the brain that are involved in attention and inhibition (i.e. prefrontal regions, striatum and limbic systems). Preliminary results from positron emission tomography (PET) scans (which measure metabolism of glucose in the brain) suggested differences in the brain of people with ADHD. Findings of decreased blood flow and decreased glucose metabolism suggest lower levels of brain activation. Early studies of the brain structure used computerized tomography(CT) scans and had mixed findings. More recent research used quantitative magnetic resonance imaging (MRI) scans, and suggested possible structural abnormalities in the prefrontal striatal areas of the brain(Geidd et al; 2001), although further study is needed to confirm these findings.

Assessment/Diagnosis of ADHD

In assessing ADHD, we use Conners 3 which is a unique tool in the field of psychological assessment because it is built from clinical experience, has a solid statistical foundation, and takes into account relevant theoretical research. Information derived from Conners 3 is combined with other forms of assessment and clinical interview to make a diagnosis.

Media coverage often suggests that ADHD is over-diagnosed. The Conners 3 helps clinicians determine if a child or adolescent is having more difficulty in a given area than other children or adolescent of the same age. This developmentally- referenced guideline helps reduce over-diagnosis by allowing for a direct comparison of an individual’s behavior with characteristic behavior found in a normative sample.

The Conners 3rd EditiontTM is the product of 40 years of research on childhood and adolescent psychopathology. It is a thorough and focused assessment of Attention-Deficit/Hyperactivity Disorder(ADHD) and its most common comorbid problems and disorders in children and adolecents. It is a revision of the Conners’ Rating Scales-Revised(CRS-R; Conners, 1997), and integrates the same key elements as its predecessor with a number of new features, such as Validity scales, assessment of executive functioning, and strengthened linkage to Diagnostic and Statistical Manual for Mental and Behavioral Disorders (DSM-IV-TR; American Psychiatric Association, 2000). The Conners 3 is a multi-informant assessment of children and adolescents between 6 and 18 years of age that takes into consideration home, social, and school settings. Raters include parent, teacher and the child in concern (if he/she is 7 years or above)

The Conners 3 helps in developing an individualized treatment plan. Results from the Conners 3 will be used to help form individualized intervention plans for children, including individualized Education Programs (IEPs). Elevated Conners 3 scores suggest specific behaviours that require intervention.

It also helps in monitoring an individual’s response to treatment. The Conners 3 (particularly the Short and Index forms) can be re-administred frequently to monitor whether an individual child is responding to a particular treatment plan. Results from re-administration may indicate the need for modifications that would make the intervention more effective.

Evaluating an intervention program is another goal that the Conners 3 can be used to achieve. It helps to evaluate the effectiveness of an entire treatment program, such as one that might be implemented in at home and in school.

Brief History of ADHD

There is speculation about a possible reference to ADHD in many historic and literary documents including writings by Hippocrates and Shakespeare. The first known documented description of ADHD as a disorder was in 1902, when Dr. George still gave a lecture about a group of children with a “defect in moral control” (still 1902, p. 1008). These children reportedly demonstrated poor self-control, over-activity and fidgetiness among other symptoms. The following is a sequential timeline of the various diagnostic terms that have been used to describe the core cluster of features currently labeled “ADHD”.

1937: Dr. Charles Bradley published the results of his study involving children with “organic brain syndrome” who showed improved behavior and school performance in response to Benzedrine (dextroamphetamine sulfate; Bradley 1937).

1952; original diagnostic and statistical manual (DSM; American Psychiatric Association[APA],1952) used the term minimal brain damage(MBD) or hyperkinetic syndrome.

1957 hyperkinetic impulse disorder (Denhoff laufer and Solomons, 1957) attributed symptoms to cortical overstimulation.