Envision a rainbow or an umbrella. Individuals with autism spectrum disorder—a group of complex disorders of brain development—can fall along any point of that arc, depending on whether their difficulties are mild, moderate, or severe. Traits the disorders share, in varying degrees of severity, include difficulty with social interaction, verbal and nonverbal communication skills, eating behaviors, and exhibiting repetitive behaviors, according to Autism Speaks and the American Speech-Language-Hearing Association.
People on that broad spectrum can have motor coordination and attention problems, intellectual disabilities or gifted abilities, and, in some cases, accompanying physical problems ranging from gastrointestinal issues to sleep difficulties.
Following are the five classifications that fall under autism spectrum disorder, listed from mild to severe:
Asperger’s syndrome. A high-functioning form of austism in which individuals lack social and communication skills but possess normal intelligence and verbal skills. A distinct characteristic of children with Asperger’s is that they tend to be obsessive with an activity or object, making them oblivious to their surroundings.
Pervasive developmental disorder—not otherwise specified (PDD-NOS). A catch-all diagnosis meaning that a child may show symptoms of autism but does not fall into another category on the spectrum.
Autistic disorder or classic autism. These individuals exhibit more severe symptoms than those with Asperger’s and PDD-NOS. They lack intuitive social skills, which can make them react adversely to being touched and making eye contact. They tend to exhibit more severe cases of repetitive behavior, gestures, and unresponsiveness. They can be prone to hurting others and causing self-injury.
Childhood disintegrative disorder. Children with this disorder show a pronounced loss of motor, language, and social skills, and a dramatic loss of vocabulary skills. Other medical conditions associated with it are loss of continence, seizures, and low IQ.
Rett syndrome. A severe form of autism in which children show deteriorating mental, social, and communication skills. These children are unresponsive, avoid social contact, and can stop talking completely. Reduced muscle tone causes difficulty, and children often have other medical conditions ranging from scoliosis to heart problems to sleeping problems.
About one in 68 American children is identified as on the spectrum, according to the U.S. Centers for Disease Control and Prevention, and studies show that autism spectrum disorder is four to five times more common in boys than girls.
While researchers have not found one definite cause of any of the forms of autism, scientists have identified more than 100 genes or mutations that increase the risk that a child will develop autism, according to Autism Speaks. Most cases, though, involve a complicated combination of genetic risk and environmental factors.
Medical experts say autism can’t be definitively diagnosed until around 18 to 24 months, but research indicates that infants may show early signs like no back-and-forth sharing of sounds, smiles, or other facial expressions by nine months or no babbling or back-and-forth gestures like pointing by 12 months. Some children develop normally, then begin to lose their speech or social skills and develop autism in the early toddler years. A comprehensive guide and video can help parents determine their next steps.
Above all, if you suspect something is not right with your child at any time, talk to your doctor and research your state’s early intervention services to have your child screened for autism. Research shows that early diagnosis and intervention are key to the best outcomes.