Autism Spectrum Disorder (ASD) is a complex neurobiological disorder that typically appears during the first three years of life and lasts throughout one's lifetime.  ASD is the result of a neurological disorder that affects the normal functioning of the brain and impacts communication, social interaction, behavior and one's senses.  Individuals with ASD typically have a hard time understanding verbal and nonverbal communication and learning appropriate ways to relate to others.  Autism is a spectrum disorder that is defined by a certain set of behaviors; however individuals with ASD can exhibit any combination of these behaviors and the degree of severity will vary.  Although autism is not curable, there are many treatment options available.  Studies have shown that with early diagnosis and interventions, the outcome for someone who lives with ASD can be improved significantly.

ASD was one of five disorders that fell under the umbrella of Pervasive Disorder Not Otherwise Specified (PDD-NOS).  The five disorders were: Autistic Disorder, Asperger’s Disorder, Retts Disorder, Pervasive Development Disorder (PDD) and Childhood Disintegrative Disorder.  These subtypes of PDD-NOS, are no longer included in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and are no longer used in the classification of Autism Spectrum Disorder. 

As you explore the causes of autism, you are likely to come across many controversial theories.  It is important to understand, that the exact cause of autism is simply not known.  Research has pointed to several possible factors, including genetics (heredity), metabolic or neurological factors, environmental factors, certain types of infections, and problems occurring at birth, but no known cause has been detected.  Further research is still very much needed.