I've recently read a very interesting summing up of the evidence surrounding stem cells and the production of new neurons ('neurogenesis') in the adult brain. I wanted to do a thread on it but I haven't quite got my head around it all just yet. The basic opinions of the author of the piece I've read (which I found very convincing) are as follows:-

1. Contrary to previous opinion, the adult mammalian brain is definitely capable of producing new brain cells throughout life in certain areas, chief among these is the hippocampus (which is involved in memory). Most of the evidence is from neurogenesis in adult rodents.

2. There is less evidence of this occurring in higher primates (including man) however the author considers the evidence to be sufficient to say that yes, this does occur in man as well.

3. There is huge potential for using this in neurological rehabilitation in the future, however, there is probably not enough evidence and understanding of it to use it effectively right now.

4. What evidence there is suggests that depression will reduce neurogenesis, and that exercise, an 'enriched (stimulating) environment' and new learning will increase it. It may be that these factors have to take place within a specific time frame in relation to each other.

There is no mention of dietary supplements contributing to this process (though they are a good idea generally). On looking at your son's current symptoms, I would not advise that he exercises, is stimulated or tries to learn anything new at the moment. When he has rested long enough to tolerate these things, they would be a good idea.