Over recent years, many theories about the causes of autism have been put forward, yet at present we have no definitive answer as to the question. Commonly known as Autistic Spectrum Disorder, or ASD, and covering many different degrees of symptoms experienced by sufferers, the condition affects lots of children every year, who continue to have the symptoms into adulthood.
Research in the Contributing Factors
Research has shown that it is likely that several different factors contribute to a diagnosis of ASD, often involving a complex mix of causal elements. Doctors are also now able to divide ASD into two types – primary ASD and secondary, though the latter is far less common (around 10% of cases). While secondary ASD is thought to be triggered by underlying medical conditions, primary ASD does not seem to link back to a pre-existing medical complaint. Such complaints, in the case of secondary ASD, include Fragile X syndrome, tuberous sclerosis and Rett syndrome, all of which are rare conditions, particularly the latter.
Is There a Genetic Link?
In terms of primary ASD, there are four main factors that researchers point to, though they often disagree about which factors might form the primary causes of the condition. The first factor, genetics, however, draws a general consensus of opinion. There is evidence of ASD running in families, with particularly high instances of both children in a pair of twins developing it (60%). No specific autism gene has yet been discovered, though, and there is no test currently available to screen for ASD.
A popular line of enquiry has been into the environmental factors involved. Whilst most researchers accept that genetics probably play a part, some think that environmental factors form the triggers that turn a person’s susceptibility for ASD into full ASD symptoms. These factors include the mother smoking or having a bacterial or viral infection during pregnancy, the father being over 40 at the child’s conception, exposure to pesticides, and air pollution. Research into air pollution and pesticides is on-going, but there is already convincing evidence that the first three factors listed do make an impact on a child’s likelihood of developing ASD.
Neurological factors have also been looked into, focusing on the amygdala – the part of the brain that matches your emotions to the situation you’re in. Findings have suggested that connections between the amydala and other parts of the brain are jumbled up, therefore resulting in the emotional and physical sensations often experienced by people with ASD. Other research, into mirror neurones, points to ASD sufferers being more susceptible to motor neurone dysfunction, leading to difficulties with language and interactions with others.
People often talk of psychological factors contributing to ASD, and mention an idea known as the ‘theory of mind’, which describes being able to put yourself in someone else’s shoes. It’s thought that children with ASD do not develop this ‘theory of mind’, or at least not fully, which then leads to difficulties in understanding others’ and their own emotional states.