I don't k now what to tell you...lol. psychiatrists ALWAYS say more, more, more. That's been my own experience with my own self. If he starts acting even edgier and can't sit still and says he feels like jumping out of his skin or says his body is racing...take him seriously. Akathesa is NOT a panic attack. It's a bad reaction to medication and it feels horrible. I had it once the day of my son's eighth grade graduation. The doctor gave me Valium and told me to take one an hour so I could sit through the ceremony, and it helped a lot. I never took that medication again.
I had a lot of bad side effects to Lithium. Watch your son. This drug does produce some pretty bad side effects in some people. Sonic was on it for three years and he wet his bed every day of those three years and not once since. That's but one possible side effect. Worse is the stuff I had...I felt like a walking zombie, like I was in some sort of dream. I became suicidal. Guess what the psychiatrist said? "More! More! More!" Being an adult, I didn't listen and I went to somebody new who took a blood level which showed I was at a toxic level. Has your son had a level drawn?
Good luck with all this. I hope it helps him more than it did me or Sonic.