Hi Carol,
Most of the supplements sometimes recommended for anxiety should not be taken while on antidepressants. Specifically, avoid Tryptophan (L-Tryptophan), 5-HTP and St Johns Wort.
Your son could try fish oil/omega-3 and inositol, and possibly curcumin (not recommended for smokers).
But clear it with your son's physician first.
The only non pharmaceutical treatments with a proven track record are the cognitive behavior therapies such as
CBT and
Rational Emotive Behavior Therapy (REBT)
HTH
Ian
NOTE: I am not a doctor, and more importantly, I'm not
your son's doctor so the above advice is necessarily of a general nature which may or may not apply to him. Always consult a health provider before acting on anything you've read here.
Posted by Carol