Vitamin B6

I would simply concentrate on providing a balanced and non-processed set of foods for an 8 year old.  I have NEVER read any better advice.

I mean I do take B6 everyday and have done so for years and it helps me tremendously. I have not had any of these ‘detrimental side effects’ that people speak of. The only side effects I have had is feeling genuinely better and less anxious. So it’s a win for me. I am an adult so I take quite a high dose as your son is a child I would agree with bunny and recommend you speak to a nutritionist or some other kind of professional to determine what dose of B6 would be appropriate for your child. I am not qualified to tell you what dose would be effective for your son. Only a qualified experienced professional would know this information. For me B6 lessens my sensory sensitivity and enhances my self confidence and ability to approach others in social settings. It also seems to help me read social cues better as my mind seems to be a bit more rational and slower enough to process better what people are saying. The science behind it goes something like this - it enhances GABA levels which causes a reduction in anxiety. 

I've replied, including some links for your reference, but the post has been placed in spam quarantine, so will appear in due course, once it's been released by the mods.

The gist is that I suggest you consult your son's GP because a) we can't give medical advice here and b) there can be detrimental side effects.