Autism spectrum disorders: a lifetime of difference

Autism Spectrum Disorders (ASD) are developmental disorders characterised by limitations in social interaction, communication and imagination. They are often associated with stereotypical or rigid behaviour patterns. The term ‘spectrum’ is used to reflect the fact that the disorder takes different forms in each individual with ASD. Most ASD cases can be classified into one of the following three groups: childhood autism, PDD-NOS (pervasive developmental disorder – not otherwise specified) and Asperger’s disorder. In childhood autism, depending on their age, affected individuals make little or no contact with the outside world. Conversely, those with PDD-NOS or Asperger’s disorder are characterised not so much by a lack of contact, but more by dysfunctional interactions with those around them.
The causes of ASD are unknown. What is clear, however, is that ASD is largely hereditary, with a higher incidence among boys/men than among girls/women. Environmental factors also appear to be implicated in these disorders, but the exact mechanism involved has yet to be elucidated. Approximately half of those with ASD also suffer from some form of intellectual disability.