Symptoms and severity vary greatly, and some symptoms are evident in children and adults without ASD. The spectrum of ASD includes autistic disorder, childhood disintegrative disorder, pervasive developmental disorder-not otherwise specified, and Asperger syndrome.

Autism spectrum disorders affect both communication and social skills. The severity of symptoms can vary greatly. Possible signs and symptoms include:

-not speaking or very limited speech
-poor play skills
-loss of words the child was previously able to say
-difficulty expressing basic needs and wants
-poor vocabulary development
-problems following directions or finding objects
-repeating what is heard (echolalia)
-difficulty answering questions
-robotic speech production and/or speech that is high-pitched
-poor eye contact
-overly focusing on a topic or object (perseveration)
-difficulty making friends
-crying, laughing, becoming angry at inappropriate times
-sensory integration disorder (being either very sensitive or not sensitive enough to touch, light, or sounds)
-rocking, hand flapping, or other self-stimulating movements
-inattention to the environment (sounds and things around the child)
-excessive difficulty with changes in routine
-unusual attachments to objects
-no fear of real dangers
-feeding difficulties
-sleep problems