Autism isn't defined by a single individual symptom. Sometimes, even professionals may find it hard to diagnose the disorder. However, there is an autism symptoms checklist, and if you have a child who has multiple of the symptoms on this list, you may want to ask for your child to be evaluated and screened.

1. Speech Differences and Delays

The autism symptoms checklist starts with speech. Almost all autistic children have speech and language problems. However, what these problems are can vary greatly. Some of the things to look out for include:

– Severely delayed speech

– No speech at all

– Odd sounding language use

– Flat, monotonous voice

– Repeating phrases or words picked up from television

2. Unusual or Delayed Play Skills

Autistic children have different interactions with playmates and toys. Some of the things to look out for include:

– Lining toys up in a specific order, rather than playing in an imaginative way with them

– Preferring their own company almost exclusively

– Demanding that playmates do things in a very specific, and soon predictable, way

3. Unusual Reactions and/or Physical Behaviors

The next element on the autism symptoms checklist is about physical behaviors. These are often very different from other people. Some common signs and symptoms include:

– Self-stimulation through flapping or rocking, often in an effort to calm down

– Low response to external stimuli, including pain

– Avoiding eye contact with others

– Having abnormal responses to pain, touch, taste, smell, sound, and light

4. Common Physical Symptoms

Children with autism also often experience certain specific physical symptoms, including:

– Problem sleeping

– Issues with fine and gross motor skills

– Intestinal and stomach problems, including an increase in GI problems, diarrhea, constipation, vomiting

– Delays in coordination

– Clumsiness

5. Less Common Signs of Autism

There are a number of symptoms that are often seen with autism, although the link between the disorder and these behaviors has not been exactly determined. Some of the things to look out for include:

– Having an above average ability to read or count, although they often do not understand what they are reading

– Responding in unique ways to numbers, letters, colors, or sound

A very small percentage of autistic people are so-called "autistic savants", who usually have incredible abilities such as performing complex calculations, memorizing information, playing the piano, and more. This type of autistic behavior was explained more clearly in the movie "Rain Man", where Dustin Hoffman played Raymond, the autistic older brother of Tom Cruise.

It is very important to understand that having any, or even many, of these symptoms does not necessarily mean that your child is autistic. Rather, the autism spectrum is very wide, and almost every individual will have some signs of autism. Additionally, two people with autism are completely different, with them ranging from being able to live fully independently in adulthood, to not being able to look after themselves at all and requiring permanent care. If you do have any concerns about your child, you should make an appointment with your physician for a referral to a specialist.