There are several types of autism, which has varied symptoms. It is believed that autistic spectrum disorder (ASD) can be divided into three types. These are the Aspergers' syndrome, Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), and Autistic Disorder Not Otherwise Specified (ADOS). The ASD type is the first and the most severe type. It was found to have symptoms similar to those of schizophrenia.
ASD, Aspergers' syndrome, PDD-NOS and ADOS are the three types of autism spectrum disorder. These are the four diagnostic labels given to a wide group of neurodevelopmental illnesses. They are commonly referred to as pervasive developmental disorders and affect as many as one in every 150 children. These four types of autism spectrum disorder are used for different purposes. For example, ASD is used as the name for the developmental disability that affects approximately one in every 50 children. Also, Aspergers' syndrome is used for this developmental disorder that affects approximately one in every 60 children. On the other hand, PDD-NOS and ADOS are used for these developmental disorders that affect approximately one in every 100 children.
Different factors can cause autism spectrum disorder in children. It is known that genetics, biological abnormalities and brain abnormalities are the major causes of autism spectrum disorder. However, environmental factors like exposure to toxins and other toxins can also contribute to this condition. In some cases, other environmental factors autism signs may trigger autism symptoms, which may also lead to the development of autism spectrum disorder. These causes and triggers can be from the patient's early childhood to his or her adulthood. Autism spectrum disorder can also develop due to genetic abnormalities in other relatives of an individual. However, the most common causes of autism spectrum disorder in children are environmental factors.