Recognizing early signs of autism spectrum disorders (ASDs) and seeking early intervention can make a world of difference in the life of a child with autism. Here, we share what you need to know about spotting signs of autism early.

When do early signs appear?

Research now suggests that children can show signs of autism as early as 1 year old. However, timing varies, as Autumn W., an occupational therapy assistant who works with children with autism, explains: "There is early onset autism (before 2 years of age) and late onset (where a child meets most milestones on time and seems to be developing normally until a marked regression of skills)."

What are typical signs that a child has autism?

No child with autism is the same. There is a very large spectrum of behavior exhibited by children with autism, and there is no "typical" group of behaviors that all children with autism exhibit. As Jana T. shares: "All autistic children are unique in their own ways. There is no typical behavior of an autistic child."

What are the developmental "red flags" to watch for?

While there isn't a checklist of signs that will indicate your child certainly has autism, Autism Speaksdoes cite each of the following "red flags" as an indicator that a child is at risk for atypical development and should have an immediate evaluation:

• No big smiles or other warm, joyful expressions by 6 months or thereafter.
• No back-and-forth sharing of sounds, smiles, or other facial expressions by 9 months or thereafter.
• No babbling by 12 months.
• No back-and-forth gestures — such as pointing, showing, reaching, or waving — by 12 months.
• No words by 16 months.
• No two-word meaningful phrases (without imitating or repeating) by 24 months.
• Any loss of speech or babbling or social skills at any age.

What are other possible signs?

In addition to the milestones noted above, there are many possible signs and symptoms of autism, which include social, communication, and behavioral differences.

As Autumn W. relays: "In early onset [autism], there will be a marked delay in several milestones, particularly in speech. The child may avoid eye contact and resist being held. The child may develop an irregular gait (toe walking, walking on insteps, or never relinquishing a 'high guard'). Autistic children often fixate on objects, exploring every aspect of the object. Most autistic children will self-stimulate (i.e., rocking back and forth, visual stimulation by waving their hand in front of their face, tapping, hitting themselves, and repetitive auditory stimulation). Oftentimes, they appear to be in their own world, oblivious to their environment."

Other signs readers highlight include echolalia (repeating sounds without understanding them); sensitivity to sounds, light, textures, touch, and smells; lack of empathy/understanding emotion; or movements like flapping arms, rocking, rubbing hands or fingers together, and head banging.

What are signs of late onset autism?

In addition to early onset signs, it's important to look for signs of regression from typical development. According to the American Academy of Pediatrics, approximately one quarter of children with autism will seem to have normal development until about 18 months, after which they will:

• Stop talking (if they had begun speaking words).
• Stop waving goodbye.
• Stop turning the head when the name is called.
• Withdraw into a shell and seem more distant and less interested in surroundings.

These changes may occur gradually or suddenly.

For a detailed list of possible signs of ASDs, refer to this overview of autism spectrum disorders by the American Academy of Pediatrics.

Finally, trust your gut, advises Stacy H.: "Go with your gut! Push for the evaluations! Who knows — maybe you are just overthinking things and worrying too much, but then again, maybe you are dead-on. That evaluation could make a world of difference in early intervention and really change your child's life!"