A new viral tool can selectively control different types of neurons that dampen brain activity in rodents, monkeys and people.

Autistic people who are hyperactive or have difficulty controlling their own impulses are the most likely to show ongoing self-injury.

The severity of autism tracks closely with that of attention deficit hyperactivity disorder.

The brains of autistic children show few differences from those of children with attention deficit hyperactivity disorder, or even of controls.

Heightened sensory perception in toddlers with autism may predict sleep problems at around age 7.

Traits linked to autism and attention deficit hyperactivity disorder tend to co-occur even in adulthood.

Differences in sleep and circadian rhythm may distort the results of autism studies.

Researchers have used light to manipulate neurons that dampen brain activity in rhesus macaques.