Just a postscript: When I mentioned drugs, I meant any drug, not just drugs like heroin. Most drugs can have a vast number of side effects. Many of the side effects are rare but your son just might be one of those people who react badly to a drug that seems safe enough for most people.

When he gets to a medical professional, it would be helpful if he could describe the hand tremors, asking himself how often they happen.Does anything seem to trigger them? How long do they last, or are they constant?