None. The doctor who published a paper years ago linking the vaccine MMR (that had a small amount ofthimerosal- a mercury salt) with autism (not add) has since been exposed as a fraud. "anti-vaccine" people have tried to connect vaccines to other disorders, but all scientific research studies have disproved any causal links between vaccines and and autism or any other related conditions.
Less mercury now. The amount of mercury in vaccines is zero, in most current vaccines. Many never had it in the first place. Http://www. Fda. Gov/biologicsbloodvaccines/safetyavailability/vaccinesafety/ucm096228 sadly, the refusal of parents to accept vaccines for their children has caused many deaths, many times, over the decades: http://www. Who. Int/bulletin/volumes/86/6/08-030608/en/ the recent scare is only one.
Mercury & ADHD. High mercury levels in the blood was found to be associated with add, according to study from hong kong, where consumption of deep sea fish is high.
Possibly, but... Mercury poisoning can cause a variety of physical problems and behavioral and mental changes, some of which may look like adhd. However, it is not a "cause" of adhd, even though there may be many overlapping symptoms. Any heavy metals, lead being the most common, can cause mental changes that look like adhd. Adhd is a chronic disorder probably present from birth.
No. There have been no suggestion that the amount of mercury present in past vaccines can cause or worsen adhd. Lead poisoning can cause adhd symptoms, and it is quite likely that mercury poisoning could too--but that would be at much higher doses and is a direct toxic effect on brain function.
No. A number of medical societies looked at whether thimerosol is linked to adhd or autism, and no link was found. The type of mercury is different from that found in the environment and does not build up in the body the way environmental mercury does.