Analysis of DNA and lifestyle data from a representative group of 2,500 U.S. middle- and high-school students tracked from 1994 to 2008 in the National Longitudinal Study of Adolescent Health has revealed that lower academic performance was associated with three dopamine gene variants. Having more of the dopamine gene variants (three rather than one, say) was associated with a significantly lower GPA.
Five years ago I reported on a finding that primary school children exposed to loud aircraft noise showed impaired reading comprehension (see below). Now a small Norwegian study has found that playing white noise helped secondary school children with attention problems, but significantly impaired those who were normally attentive.
A study following over 300 Mexican-American children living in an agricultural community has found that their prenatal exposure to organophosphate pesticides (measured by metabolites in the mother’s urine during pregnancy) was significantly associated with attention problems at age 5. This association was stronger among boys, and stronger with age (at 3 ½ the association, although present, did not reach statistical significance — perhaps because attention disorders are much harder to recognize in toddlers).
While brain training programs can certainly improve your ability to do the task you’re practicing, there has been little evidence that this transfers to other tasks. In particular, the holy grail has been very broad transfer, through improvement in working memory. While there has been some evidence of this in pilot programs for children with ADHD, a new study is the first to show such improvement in older adults using a commercial brain training program.
A national Swedish study involving the 1.16 million children in a national birth cohort identified nearly 8000 on the country's Prescribed Drug Register as using a prescription for ADHD medication (and thus assumed to suffer from severe ADHD). These children were significantly more likely to come from a family on welfare benefits (135% more likely), to have a mother with only the most basic education (130% more likely than those with mothers with university degrees), and to come from a single parent family (54% more likely).
A rat study shows how Ritalin improves concentration and, it now appears, speed of learning. The study reveals that it does this by increasing the activity of dopamine at two specific types of neurotransmitter receptors in the amygdala. The dopamine receptor tagged “D2” appears to control the ability to stay focused on a task, while the D1 receptor underlies learning efficiency. The finding may help the development of better-targeted drugs.