PARENTS are being warned that common head lice treatments can increase their child’s risk of severe behavioural issue.
Early exposure to pyrethroids, a common insecticides found in household items, can affect developing brains causing autism, researchers from University of Toledo, US, found.
Headlice treatments can increase children’s risk of autism and ADHD
The neurological issues, which also includes attention deficit hyperactivity disorder (ADHD), are triggered by a chemical change in the brain, they said.
Lead author, Dr James Burkett, said: “Our study adds to the evidence that these chemicals might not be as safe for children and pregnant women as we once believed.”
Around 700,000 Brits live with autism, according to the National Autistic Society.
The lifelong condition affects people in different ways, often causing difficulties with social communication and interaction.
Autistic people are also more likely to prefer strict routines, such as eating the same food every day, be sensitive to sound light or touch and be highly focused on interests or hobbies.
Scientists are not sure what exactly causes the disorder, but a family history, older parents and pregnancy or birth complications can all increase the risk.
Meanwhile, some 2.6million Brits live with ADHD, according to ADHD UK.
Up to five per cent of school-aged children and four per cent of adults may be battling with symptoms ADHD, the NHS says.
The disorder, which is often diagnosed in childhood, often sparks symptoms of inattentiveness, hyperactivity and impulsiveness.
Previous research found higher rates of brain development problems in places where the insecticide was frequently used, sparking interest in a possible link between the chemicals and autism.
Pyrethroids are present in many consumer products in the UK, including animal shampoos.
The latest research, published in PNAS Nexus, suggested even low-level exposure to the chemical can affect developing brains.
It studied the offspring of female mice who were exposed to small doses of the pyrethroid insecticide deltamethrin before, during and immediately after pregnancy.
The researchers found those mice exhibited increased hyperactivity and repetitive behaviours, less vocalisation and were more likely to fail basic learning tests compared to controls.
The young mice also experienced disruptions in their dopamine system, a chemical involved in helping us feel pleasure.
“These are all similar to symptoms human patients with neurodevelopmental disorders might have,” Dr Burkett said.
He added: “This research represents a piece of the puzzle. It is not definitive proof that the pesticide is unsafe or directly causing autism in humans.
“It may, however, suggest that the safe level of the pesticide needs to be revisited for pregnant women and children.”
Pyrethroids are present in many US head lice treatments.
The chemical was removed from treatments in the UK in 2014 after mounting evidence suggested headlice in Britain were resistant to the treatment.