How tall is he? What are his symptoms? Does anything make them better or worse? Are they consistent? Are they getting worse? Is he aware of anything which might have triggered them? Is his stress increased at home or school since 1 year ago? Any medical problems? Any surgeries? Any other medications including over-the-counter pills and herbs? Any family medical history?
Can you answer my each questions so that I can understand his condition?
His symptoms seems to be depression in addition to anxiety. Nortriptyline is a medication called TCA. It could cause a lot of side effect. He should take different kind of anti-depressant such as SSRI, SNRI, Remeron, Wellbutrin which have less side effects. It is not usual that a psychiatrist prescribes nortriptyline at first. If his doctor is not a psychiatrist, he should see a psychiatrist who will prescribe appropriate medication and provide psychotherapy.
No. But most doctor know it. Yes. He should see a psychiatrist. It is not a GI problem.