Attention Deficit/Hyperactivity Disorder (ADD/ADHD)

Attention Deficit Disorder (ADD) is a neurological disorder that affects children from the first months of their lives, through their school years, and into adolescence and adulthood. It may be accompanied with hyperactivity and is then known as Attention Deficit Hyperactivity Disorder (ADHD). The hallmarks of ADD are difficulties with attention, impulsivity and hyperactivity, which can be in varying proportions. Individuals with the disorder have difficulty paying attention, tend to act quickly without thinking things through, rarely learn from past mistakes and have trouble sitting still for lengthy periods.

INCIDENCE
Until recently, Attention Deficit Disorder was considered a disorder of childhood only. It is now recognised that up to 70 % of all children with ADD continue to exhibit symptoms of the disorder as adults. The condition does not always resolve in childhood as previously thought. When ADD persists into adulthood it is often associated with secondary problems such as anxiety, depression, gambling, drug and alcohol abuse. Management of the problem in childhood decreases the risk of these secondary problems occurring later in life.

The onset of symptoms must occur before the age of seven and persist for six months or longer. In other words, a child cannot suddenly develop ADD; rather the signs must have been present for a relatively long time. No two individuals with ADD present exactly the same profile i.e. a child may have poor concentration and be impulsive without being hyperactive. Since there is no “gold standard” for testing ADHD (the diagnosis made is a differential diagnosis and one of exclusion) it is necessary to pay careful attention to the developmental history of the child and to the family medical history. Recent technological advancements such as continuous performance tests (CTP’s) and the quantitative electroencephalograph (qEEG) are now being used as an adjunct to the behavioural descriptors of the DSM-IV and to select the most appropriate neurofeedback training protocols.

Incidence
ADHD and ADD are present in all populations with varying prevalence. The incidence of ADD is worldwide and figures vary because of differing criteria used for diagnosis and methods of evaluation. Research (1991) suggests that ADD affects 10-20% of the school-age population The ratio of males to females in the general population is 3:1; in clinical populations it varies from 6:1 to 9:1 due to a referral bias. The condition is often recognised later in life for girls. ADHD referrals contribute up to 30-40% of all clinic referrals. There is a greater prevalence in adopted and foster children due to the higher prenatal risk factors (addictions – nicotine, alcohol, illicit drugs, gambling & mental illness) associated with ADHD among those who give their children up for adoption or have their children removed from their homes.

Worldwide the incidence is:
Australia 3-5% China 11%
USA 3-8% Italy 12%
Germany 8% New Zealand 13%
United Kingdom 10% Spain 16%
(Dr Anna Orgill 1995)

Research with twins in Australia (Levy and Hay 1995) indicates a 91% concordance of ADHD in monozygotic (identical) twins. Similar studies worldwide (Biederman et al 1992; Faraone et al 1993; Gillis 1992; Dykman & Ackerman 1991) also reflect the same ratio. Dizygotic twins have the same concordance as other siblings. The concordance for other siblings is between 30 and 40% depending upon who you believe.

However, two recent studies (2010) suggest that ADHD could be potentially misdiagnosed in nearly 1 million children in the USA simply because they are the youngest in their kindergarten class. The first study by Dr Todd Elder, assistant professor of economics at Michigan State University, looked at a sample of nearly 12,000 children from the Early Childhood Longitudinal Study Kindergarten Cohort (June 2010). His results found that “the youngest children were significantly (60%) more likely to be diagnosed with ADHD and to be prescribed behavior-modifying stimulants such as Ritalin than their older classmates”. According to Dr Elder, “the “smoking gun” was that the diagnoses depended on the children’s age relative to classmates and the teacher’s perceptions of whether they had symptoms”. He continued to say that there was “a big difference between a five-year-old and six- year old” and urged teachers and medical practitioners to take that into account when evaluating children for ADHD.

Furthermore Elder stated that, “medicating such children inappropriately was a cause for concern not just because of the effect of long term stimulant use on their health but also because it costs a lot of money and he estimated about 320 to 500 million US dollars is being wasted on unnecessary medication of young children for ADHD, of which 80 to 90 million is funded by Medicaid”. Finally, his study estimated that the overall misdiagnosis rate in the USA is approximately 1 in 5. This suggests that around 900,000 of the 4.5 million children currently diagnosed with ADHD have been misdiagnosed.

The second study (August 2010) which included researchers from North Carolina (NC) State University, Notre Dame and the University of Minnesota drew very similar conclusions to those of Elder’s study. Dr Melinda Morrill, a research assistant professor of economics at NC State and co-author of the study, found that children who were born after the cut off date for kindergarten were 25% less likely to receive a diagnosis for ADHD when compared to their “relatively young-for-grade” peers” (i.e. those born just before the cutoff date). Misdiagnosis in five year olds was due to lack of maturity and not because of “underlying biological or medical reasons,” said Morrill.