An Anthropologist on Mars: Seven Paradoxical Tales

by Oliver Sacks

That the disposition to autism is biological is no longer in doubt, nor the increasing evidence that it is, in some cases, genetic. Genetically, autism is heterogeneous—it is sometimes dominant, sometimes recessive. It is much more common in males. The genetic form may be associated, in the affected individual or the family, with other genetic disorders, such as dyslexia, attention deficit disorder, obsessive-compulsive disorder, or Tourette’s syndrome. But autism may also be acquired. This was first realized in the 1960s with the epidemic of rubella, when a large number of babies exposed to this prenatally went on to develop autism. It remains unclear whether the so-called regressive forms of autism—with sometimes abrupt losses of language and social behavior in two- to four-year-olds who had previously been developing relatively normally—are genetically or environmentally caused. Autism may be a consequence of metabolic problems (such as phenylketonuria) or mechanical ones (such as hydrocephalus).1 Autism, or autismlike syndromes, may develop even in adult life, though infrequently, especially after certain forms of encephalitis. (Some of my Awakenings patients, I think, had elements of autism, too.)