Autism Spectrum Disorder has been rising in the United States (an increase of 40% since 2000 according to the CDC) since Dr. Kanner discovered it in 1943. This is rise doesn’t have a certain contribution however due to its ever changing standards that qualify someone in the spectrum.
In majority, Autism is mainly caused by genetic factors that can predestine a child to impaired social and communication behaviors but maybe even heightened intelligence. However, in a paper published in 2013 that looked at environmental factors associated with Autism, stress seemed to stick out like a sore thumb.
How can stress cause a neurological disorder? The paper talks a lot about how prenatal stress can influence the development of the baby and even cause changes that previously would not have been a factor. They still think that genetics is the leading cause but that stress may play a role in increasing the risk.
An important system in the body is the HPA axis or hypothalamic-pituitary-adrenal axis that is responsible for the neuroendocrine adaptation component of the stress response. The stressor signals to the hypothalamus to start a cascade of hormones to be processed until a certain blood concentration of cortisol this protection is seemingly achieved and the cortisol exerts negative feedback to the hypothalamus.
One study looked at autistic children versus typical children cortisol circadian rhythm. They found that both groups showed expected circadian variation with higher cortisol concentration in morning than in the evening samples. The children with autism, but not typical children, showed a more variable circadian rhythm as well as statistically significant elevations in cortisol following exposure to a novel, nonsocial stimulus.
The HPA axis can also modulate the immune system in response to a stressor, with high levels of cortisol resulting in a suppression of immune and inflammatory reactions. This helps to protect the organism from a lethal over activation of the immune system, and minimizes tissue damage from inflammation.
With repeated exposure to stressors the HPA axis can become sensitized and no longer function correctly under stressed conditions causing dys-regulation of the immune system at a critical time in development.
Stress is a mainstay in our society nowadays, with economics being its pusher. Taking time to relax while pregnant should be kept in mind, since many implications of stress are now being realized.
Are We Too Stressed?
Interesting. If autism is related to maternal stress, have any correlations of autism and socioeconomic status been found? Do autism diagnoses go up with the children who were gestated during stressful events, like 9/11 or the economic crisis, and then down in more peaceful times? In less stressed countries, is autism less prevalent?