Regarding the Positive Effects of Propranolol in Autism

Copyright 2013, James Michael Howard, Fayetteville, Arkansas, U.S.A.


It is my hypothesis that increased maternal testosterone is involved in the mechanism of autism and the increase in incidence of autism.  The basic disorder of autism resides in changes in growth and development of the brain caused by differential absorption of dehydroepiandrosterone (DHEA).  The positive effects of propranolol may be demonstrated to directly affect availability of DHEA.

I think increased maternal testosterone exposure increases androgen receptors which absorb dehydroepiandrosterone (DHEA) for gene activity.  This effect stimulates increased connectivity of brain regions at the expense of other regions because of super-stimulation of androgen receptors at times of brain growth and development of the brain in utero.  Therefore, these regions exhibit increased connectivity, again, at the expense of other areas of brain connectivity.

Once formed, these areas of increased connectivity will use DHEA at the expense of other regions for neuronal activity.  Therefore, DHEA should be low in an autistic individual.  This has been demonstrated.

It is my hypothesis of 1985 that cortisol (stress) evolved to counteract the positive effects of DHEA on neuronal function.  That is, cortisol reduces initial motivation produced by DHEA to continue during “fight or flight” circumstances.  An increased cortisol to DHEA ratio also reduces the effects of DHEA in tissues other than the brain.  Therefore, in individuals of low DHEA, events which increase cortisol will adversely affect the positive effects of their low DHEA.  I suggest this is why autistic children are so negatively affected by disruptions of their routines.  … a high DHEA to cortisol ratio is positive.

Propranolol is proven to significantly increase the DHEA to cortisol ratio (Journal of Endocrinological Investigation 1998; 21(3):148-153).

I suggest positive effects of propranolol in autistic individuals results from an increase in DHEA.  This could increase function of brain areas that normally do not have access to DHEA.

(If you are interested in my explanation of autism in detail, please visit: “A Possible Explanation of Autism based on Elevated Maternal Testosterone:  A Mechanism that may Explain Differential Growth and Development,” at:  At this link, you may also reach my other links regarding autism.)