Jonah, no substance, with the possible exception of Wonderbread, is harmless, but working out the ill effects of pot are tricky, to say the least. Smoking marijuana, like smoking cigarettes, won’t do your lungs any favors, but that difficulty can be avoided by brownies or (if they were commercially available) vaporizers. On the psychological impact, there is some evidence to suggest that heavy (and note that word) pot use can be enough to tip a schizotypal user over into full fledged schizophrenia. Schizophrenics may also face an additional problem. Often that disease (at least in its earlier stages) is associated with occasional psychotic episodes interspersed with long periods of normality. Again, there is evidence to suggest that prior marijuana consumption makes it far less likely that the patient will revert to normality. So is it potentially harmful? Yes. And what about your frazzled friends? Well, without knowing too much about the social circle of your teen years, I would be surprised if it included many who were potentially (or actually) mentally unstable (wait a minute, what am I saying….), but there is another explanation. Unfortunately, prohibition pushes many people who would otherwise be light users into the full drug culture. Slowness and, er, ‘burniness’ becomes a learned behavior – as does consumption of unhealthily large quantities of pot and, other, far more dangerous substances. And that’s enough to make anyone ’slow’ and ‘burny’. Burny? Burny? What is that word?