I replied to your other thread already. I think I get it now - hydrocodone is a painkiller.
I see you confirm your son experiences learning difficulties. It is the major step forward in my life, the one biggest helpful event and enlightenment when I discovered in my 40s that I have those. I recommend he join neurodiversity groups.
Some people with those experience small seizures. It has happened that the reaction to having a seizure is described as a psychotic episode. I'm not trying to push this idea eaxactly, just pointing out it has been known. By coincidence I received an alert to this link only the other day.
Donna Williams’ Blog Blog Archive My Experiences With Atypical Epilepsy
It just so happens that in my 50s I decided to ask my GP to prescribe me an anticonvulsant that is known for helping with nerve pain (noises resulted in pains in my hands - some people take it for shingles apparently) and is also reputed to help with depressions and agitations of mood (which it has proved to do for me in the months I have been taking it). It is interesting that there is this pain killing effect in ths drug and one or two similar ones like it, besides their other 'uses' and that for me the benfits are in all three areas.
I think the irritation of the constant effort of having to re-gather what is going on affects the moods.
We neurodiverse people are very different from each other of course. Also unfortunately doctors specialising in neurology and metabolism are often behind the forefront of knowledge.