There are two main categories with which to asses the cause of autism. The first is the psychogenic theory which places the blame of autism upon the parents, leaving all the responsibility of the child with the disease upon the parents but in fact this has been shown to be false because there is no proof for this theory and evidence exists that points to the biological theory.
The Biological theory is the second theory which stresses the possibilities of autism being the result of autism resulting in severe abnormalities in the brain possibly caused by genes passed down from the child's parents, complications during pregnancy or birth resulting in brain damage or viral infections. 1
The evidence for the biological theory is that autism is found to often be accompanied by neurological symptoms, mental handicap, minor congenital abnormalities (or birth defects), difficulties within the pregnancy or labour and certain medical conditions (for example, epilepsy). Further supporting evidence is the fact that autism is found to occur at the ratio four to one in males which supports the idea that autism has a biological cause and that it is equally common in all areas of culture, so it does not have a psychogenic cause since each society is different. Autism is also linked with other conditions including chromosomal or genetic conditions, metabolic conditions, viral infections and or congenital anomaly syndromes.
When studied on an individual basis, no apparent medical condition may be observed but if studied in groups various medical conditions are found to be linked, implying that in all cases there is a biological cause which caused the autism. These are instances in which medical conditions in association with the central nervous system are shown to be the cause of autism.
Some of these medical conditions are genetic including fragile x syndrome, phenylketonuria, tuberous sclerosis, neurofibromatosis, and other chromosomal anomalies.
Viral infections which effect the central nervous system and can be the cause are as follows : congenital rubella, congenital cytomegalovirus, and herpes encephalitis.
The metabolic medical conditions associated with autism are abnormalities of purne synthesis and abnormalities of carbohydrate metabolism.
The last group of medical conditions found in autism are the congenital anomaly syndromes including Cornelia de Lange syndrome, Noonan syndrome, Coffin Siris syndrome, William's syndrome, Biedle-Bardet syndrome, moebius' syndrome and Leber's amaurosis. This last group of symptoms are identifiable physical abnormalities that are present from birth. 2
All these conditions share the common feature of being associated with brain damage or malfunction. The Genetic factors, viral infections, pregnancy or birth complications and other causes all lead to brain damage which leads to a common pathway (or part of the brain) that may than lead to autism or a mental handicap, in between these two things is overlap which is where a connection can be found. Abnormalities have been found in past post-mortem (after death) studies within the frontal lobes which control planning and control, the limbic system which controls emotional regulation or in the brain stem and fourth ventricle, or in the cerebellum which controls motor co-ordination.
Doctors are discovering specific enzyme errors and disease entities within a subgroup of patients with autism through the detection of enzyme defects by biochemical methods. New information has been discovered that shows how sensory input has a role to play in selecting which group of neurons survive into adult life to form underlying cognitive and personality structures. 3
It is now known that if something has gone wrong with the genetic information encoding the components of the central nervous system, mental retardation may result. Ten to twenty per cent of all autistic cases are currently believed to have underlying genetic disease. This figure has been arrived at by population-based twin and family studies.
The first of these twin studies was that of Folstem and Rutter in which they found that thirty six percent of monozygotic twins had autism and zero percent of same sex dizygotic twins had autism. These findings showed the considerable influence of a genetic component to autism.
Vaccines may play a role in the causation of autism. The evidence includes both clinical research studies and thousands of parent reports linking autism to a vaccine. This theory is highly suppressed though for fear that it may encourage parents not to get their children vaccinated, which does more harm than good. "There seems to be an epidemic where the prevalence of autism is increasing at alarming rates throughout the US, the U.K. and elsewhere in the world." 4
There are several theories as to how this brain damage came about, one being that candida albicans, a yeast-like fungus common in all humans that causes Thrush and vaginal yeast infections when it beings to grow too rapidly. Research has been done that has shown that candida is able to produce toxins which disrupt the immune system on a long-term basis severely and there is a possibility that they can possibly even attach the brain, possibly leading to many mental disorders including depression, schizophrenia and even possibly autism.
Along with the information gathered to back up this theory, there is a possibility that a small percentage of individuals suffering with autism have developed it as a result of a severe candida infection, in these cases, if this infection were cleared, the autistic symptoms would show drastic improvement. This is theorized that the child has the candida infection passed from their mother who has had long term yeast infections or something along that line. Nystatin, Ketoconosal (Nizerol) and a regulated diet excluding certain foods (refined sugars and carbohydrates mostly) are the best approaches at treating candida but these drugs may have side affects. Keep in mind that this theory, as well as most of the theories in regard to autism are just that : theories. They have not been proved.