What does the Awakening look like in autistic adults?

Treatment of an adult with autism with rifaximin does not have as impressive an awakening response as seen in young children or even teens. I’m not certain why but suspect that by this age the parents have through trial and error learned that certain eating, medication, and environmental factors had already dampened the impact of propionic acid to a certain degree, or they are presently experiencing bacterial overgrowth from bacteria that do not produce propionic acid.