In the British Journal of Psychiatry, Dr. P. Liddle and Dr. T. Barnes wrote that schizophrenia may really be two or three separate conditions. The positive symptoms are entirely different from symptoms of autism, but the negative ones may partially overlap with autistic symptoms. Confusion of the two conditions is the reason that some doctors attempt to treat autism with neuroleptic drugs such as Haldol and Mellaril. But neuroleptics should not be the first-choice medications for autism, because other, safer drugs are often more effective. Neuroleptic drugs have very severe side effects and can damage the nervous system.
Over ten years ago, Dr. Peter Tanguay and Rose Mary Edwards, at UCLA, hypothesized that distortion of auditory input during a critical phase in early childhood development may be one cause of handicaps in language and thinking. The exact timing of the sensory processing problems may determine whether a child has Kanner's syndrome or is a nonverbal, low-functioning autistic. I hypothesize that oversensitivity to touch and auditory scrambling prior to age two may cause the rigidity of thinking and lack of emotional development found in Kanner-type autism. These children partially recover the ability to understand speech between the ages of two and a half and three. Disintegrative disorder children, who develop normally up to two years of age, may be more emotionally normal because emotional centers in the brain have had an opportunity to develop before the onset of sensory processing problems. It may be that a simple difference in timing determines which type of autism develops. Early sensory processing problems may prevent development of the emotional centers of the brain in Kanner-type autistics, while the acquisition of language is more disturbed when sensory processing difficulties occur slightly later.
Research has very clearly shown that autism is a neurological disorder that reveals distinct abnormalities in the brain. Brain autopsy research by Dr. Margaret Bauman has shown that those with both autism and disintegrative disorder have immature development of the cerebellum and the limbic system. Indications of a delay in brain maturation can also be seen in autistic children's brain waves. Dr. David Canter and his associates at the University of Maryland found that low-functioning children between the ages of four and twelve have EEG readings that resemble the brain-wave pattern of a two-year-old. The question is what causes these abnormalities. Studies by many researchers are showing that there may be a cluster of genes that can put a person at risk for many disorders, including autism, depression, anxiety, dyslexia, attention deficit disorder, and other problems.
There is no single autism gene, though most cases of autism have a strong genetic basis. If a person is autistic, his or her chances of having an autistic child are greatly increased. There is also a tendency for the siblings of autistic children to have a higher incidence of learning problems than other children. Studies by Susan Folstein and Mark Rutter in London showed that in 42 percent of the families surveyed, either a sibling or a parent of an autistic child had delayed speech or learning problems.
Genetics, however, does not completely control brain development. Studies of identical twins by Folstein and Rutter show that sometimes one twin is severely autistic and the other has only a few autistic traits. MRI (magnetic resonance imaging) brain scans of identical twin schizophrenics have shown that the more severely afflicted twin has greater brain abnormalities. The brain is so complex that genetics cannot tell every little developing neuron exactly where it should be connected. There is a 10 percent variation in brain anatomical structure that is not controlled by genetics. Brain scans of normal identical twins by Michael Gazzaniga, at the Dartmouth Medical School, showed an easily observable variation in brain structure, but twins' brains are more similar than the brains of unrelated people. Likewise, the personalities of identical twins are similar. Studies at the University of Minnesota by Thomas Bouchard and his colleagues of twins reared in different families show that basic traits such as mathematical ability, athletic ability, and temperament are highly inheritable. A summary of these studies concluded that roughly half of what a person becomes is determined by genetics and the other half is determined by environment and upbringing.
Other theories suggest that if a fetus is exposed to certain toxins and viruses, these may interact with genes to cause the abnormal brain development typical of autism. If either parent is exposed to chemical toxins that slightly damage his or her genetic material, that could increase the likelihood of autism or some other developmental disorder. Some parents suspect that an allergic reaction to early childhood vaccinations triggers autistic regression. If this is true it is likely that the vaccine interacts with genetic factors. Another possibility is immune system abnormalities which interfere with brain development. However, there is still too much that is not known, and neither parent should be held responsible for an autistic child. Scientific studies and interviews with families indicate that both the father's and the mother's side contribute genetically to autism.
The Autistic Continuum
Countless researchers have attempted to figure out what factors determine the difference between high- and low-functioning autism. High-functioning children with Kanner's or Asperger's syndrome usually develop good speech and often do well academically Low-functioning children are often unable to speak or can say only a few words. They also have trouble learning simple skills such as buttoning a shirt. At age three, both types have similar behaviors, but as they grow older the difference becomes more and more apparent.
When my speech therapist held my chin and directed me to look at her, it jerked me out of my private world, but for others forcing eye contact can cause the opposite reaction — brain overload and shutdown. For instance, Donna Williams, the author of Nobody Nowhere, explained that she could use only one sensory channel at a time. If a teacher had grabbed her chin and forced eye contact, she would have turned off her ears. Her descriptions of sensory jumbling provide an important bridge to understanding the difference between high-functioning and low-functioning autism, which I would describe as a sensory processing continuum. At one end of the continuum is a person with Asperger's or Kanner's autism who has mild sensory oversensitivity problems, and at the other end of the spectrum is the low-functioning person who receives jumbled, inaccurate information, both visually and aurally.
I was able to learn to speak because I could understand speech, but low-functioning autistics may never learn to speak because their brains cannot discriminate among speech sounds. Many of these people are mentally retarded, but a few individuals may have a near-normal brain trapped inside a sensory system that does not work. Those who escape the prison of low-functioning autism probably do so because just enough undistorted information gets through. They do not totally lose contact with the world around them.
Twenty years ago, Carl Delacato, a therapist who worked with autistic children, speculated that low-functioning individuals may have «white noise» in their sensory channels. In his book The Ultimate Stranger, he described three kinds of sensory processing problems: hyper, hypo, and white noise. Hyper means oversensitive, hypo means undersensitive, and white noise means internal interference.
In questioning many people with autism, I soon found that there was a continuum of sensory abnormalities that would provide insight into the world of nonverbal people with autism. I imagine that the extent of sensory jumbling they experience would be equivalent to taking Donna's sensory problems and multiplying them tenfold. I am lucky in that I responded well when my mother, teachers, and governess kept encouraging social interaction and play. I was seldom allowed to retreat into the soothing world of rocking or spinning objects. When I daydreamed, my teachers yanked me back to reality.