Progress toward treatments for synaptic defects in autism. Nat Med. 2013 Jun;19(6):685-94
Delorme R, Ey E, Toro R, Leboyer M, Gillberg C, Bourgeron T
... There is currently no cure for ASD; however, results from mouse models indicate that some forms of the disorder could be alleviated even at the adult stage. Genes involved in ASD seem to converge on common pathways altering synaptic homeostasis. We propose, given the clinical heterogeneity of ASD, that specific 'synaptic clinical trials' should be designed and launched with the aim of establishing whether phenotype 'reversals' could also occur in humans....
In other words, we seem to be able to make adult "autistic mice" better, so maybe we can make adult humans "better", hopefully with a different outcome than Flowers for Algernon. To put it mildly, this will be a long and tricky road.
My #1 is 16, so it's not impossible that sometime in his life, depending on his particular neurobiology, there might be a medication that might, among other things, increase his IQ score.
It won't be in the next 20 years though.