The few double blind studies that have been conducted confirm what real doctors suspected - these people are suffering from nothing more than extreme hypochondria. When MCS suffers were exposed to distilled water, but told that it contained trace elements of one of the chemicals they were afraid of, they had horrible reactions. Exposing them to water that was doped with their chemical de jour, but telling them it was pure water, evoked no reaction. Real doctors direct sufferers of MCS to real psychotherapists, who might be able to help them find relief. But most MCSers respond by writing off the real doctors as quacks, then seeking out real quacks and throwing money at them.
Quacks often prescribe homeopathy , a make believe cure for a make believe disease.
Sometimes it even works, temporarily. All cures are temporary, though, because a permanent cure would mean the MCSer would have to find another way to get attention. Evidently minorities are either too busy working or too realistic to suffer from it. Wealthy woman have other ways of getting attention and poor women, who can't afford high priced quacks, don't bother with it either. Most men prefer getting attention by shows of strength instead of shows of weakness, so hypochondria isn't nearly as common among us.