A case study is where one or a handful of people are intensely investigated and the facts of the case are reported. Case study research is both good and bad. It is good because it (1) delves deep into the complexity of one individual and (2) it can be an example of something that occurs more widely in the population. The downside is that can (1) be unrepresentative or misleading and (2) makes it difficult to draw conclusions about the implication for other people.
A recent Spanish case study published in 2011 by Juan Garcia and others is an example of what is both good and bad about case study research in ASD. Garcia documented the case of a mother of an ASD child who (1) consumed 1200mg of horsetail (Equisetum arvense), a herbal remedy that aids in weight loss one year prior to conception and (2) consumed 20g-40g of ethanol or 2-3 standard drinks per day for the first 9 days after conception and then 1 standard drink per day for a further 2 weeks and then stopped consumption during pregnancy.
The combination of the herbal remedy and the alcohol resulted in a measurable vitamin B deficiency. In addition, the consumption of alcohol during the early developmental stage resulted is known to have impacts on the embryos neuronal development. To fix the vitamin B deficiency the mother was supplied with vitamin B supplements 9 weeks into the pregnancy. If vitamin B deficiency was a contributor to ASD then this intervention proved inadequate.
Based on this information it would be relatively easy to conclude that the alcohol and the diet pills resulted in the birth of an ASD child. The news media may jump to this conclusion and quickly report “a new link found to ASD”. The results however are much more inconclusive. If the case of vitamin B deficiency and alcohol was a clear determinate then why wouldn’t the children of alcoholics automatically have ASD? It turns out that these children have foetal alcohol syndrome and although some features overlap this condition lacks the critical ASD features.
The bottom line
In summary this article is a clear warning that potential parents should get a full assessment before embarking on a pregnancy. They need to eliminate alcohol and ensure vitamin B levels are correct before pregnancy starts.