I am sorry for the confusion, now I see your whole question.
The symptoms that you describe your son having sounds as though it very likely may be either depression or bipolar disorder with a strong anxiety component. Because of his "overreaction" to the antidepressant he tried, this very well may be bipolar disorder since this often happens if bipolar disorder patients are treated too aggressively with antidepressants not balanced with a mood stablizing medication to prevent the extreme "highs". I understand that this must be very difficult to deal with since your son sounds like a very intelligent young man.
This is probably bipolar II disorder rather than bipolar I since it does not sound as though your son has had full blown manic episodes (except perhaps with the use of the antidepressant). Bipolar II is usually characterized by primarily depressed mood with occasional hypomanic episodes (elevated mood, enegery, perhaps some racing thoughts but not to the extreme of severe manic episodes). The best treatment for this is usually a low dose antidepressant along with a mood stabilizing medication such as valproic acid, lamotrigine or lithium. Counselling and sometimes anxiety medications such as clonazepam or antipsychotic medications like seroquel may also be needed.
Though I cannot recommend a specific doctor in California for you personally, I suspect that his university would have on-staff counsellors or psychologists who would be able to refer him to a local psychiatrist to confirm his diagnosis and begin treatment. If he goes to a university affiliated with a medical school (there are many in California), he also could contact the Psychiatry department there and set up an appointment.
The following link may be helpful, though since you have a background in Psychiatry you may not need this! Please let me know if you have further questions.