It's great to see research being conducted into the effect of flame retardants on kids social and behavioural outcomes.
A pilot study conducted by Oregon State University in 2017 http://oregonstate.edu/ua/ncs/archives/2017/mar/flame-retardant-chemicals-may-affect-social-behavior-young-children found "that the children who had more exposure to certain types of the flame retardant were more likely to exhibit externalizing behaviors such as aggression, defiance, hyperactivity, inattention and bullying".
"Flame retardants are found throughout the built environment in furniture, mattresses, carpeting, electronics, vehicles and more. The chemicals are added to the products and are not bound in the material, which causes them to be released into indoor environments."
What you can do to reduce your child's exposure to flame retardants is:
WASH new clothes and bedding and dry them in full sun before you wear them
BUY clothes, toys, furniture and cars that are second hand and have had time to off gas before they reach you and your family
PURCHASE organic mattresses or cots and beds
PREVENT small children from chewing on toys and clothing
REPAIR tears in upholstered furniture
WET mop and wet dust your home
WIPE and clean down the interior of your car often as seats and dashboards contain flame retardant chemicals
USE air purifiers with HEPA filters in kids bedrooms and the living room