The role of the noradrenergic system in autism spectrum disorders

Abstract

Drugs that decrease the activity of one of the chemical messengers in the brain, norpeinephrine, are sometimes helpful for patients with autism-related conditions, or autism spectrum disorders (ASD). Individuals with ASD have decreased flexibility in verbal problem solving. Activity of the norepinephrine system affects performance on such verbal problem solving tasks in individuals without neurodevelopmental diagnoses in experiments using the norepinephrine beta-receptor blocker, propranolol. In individuals without neurodevelopmental diagnoses, response to propranolol depends on how hard the task is, and it is beneficial only for difficult problems. However, in other types of patients with altered norepinephrine or altered flexibility in thinking such as individuals under stress, patients with language loss due to stroke, and individuals in cocaine withdrawal, propranolol also benefits performance for simple problems. Due to decreased flexibility in verbal problem solving in ASD, preliminary evidence suggests that they also respond more favorably to propranolol for simple problems. Future research will be necessary to determine how this cognitive response relates to the clinical response to these agents to better determine if this is a potential mechanism for treatment in ASD.