The premise is that drug and alcohol abuse is associated with an increase in autism incidence rates.
There are no formal studies proving or disproving a link, however, there is anecdotal evidence suggesting an abnormally high incidence of autism among members of substance abuse recovery groups.
Will power is a general term that denotes the application of coping skills which decrease substance abuse rates.
Therefore, if reducing substance abuse incidence results in lowered incidence of Autism, the application of will power would reduce Autism - in SOME cases.
Link to the study please.