10 years later, hopefully I can add a more definitive answer: Yes, you can smoke hops in a joint and yes you can receive pleasant, calming effects from it. The same heat that decarboxylates humulone in hop tea to calm you down is applied when lighting it on fire. Just be careful not to burn off the active ingredient that gives you that calming GABA response.
Normally when we dry hop in secondary fermentation, we are effectively substituting heat for time, and it will naturally decarb over time, that's why it works in brewing if you let it sit long enough. Decarboxylating is just a fancy way of saying "decaying" - and it means what it sounds like:
"de" remove "carb" carbon "oxylate" via oxygen aka break down carbon-based living material releasing co2 in the process, this is a layman's understanding what "decay" is! Many plant-based compounds and foods require decarboxylation to get the maximum desired effect - even broccoli.
You usually need to decarb herbs delicately and over as much time as possible, as with cannabis, mushrooms, etc. to get the most out of the ingredient; for example with Amanita Muscaria you can never get more than 30% decarb conversion from ibotenic acid -> muscimol I don't know the % with hop but it seems lossy (anecdotally), it's feels 3x stronger when brewed as a tea.
But if you're determined to smoke it, if the smoke smells just like a hop - bitter and stinky, you're smoking it correctly, that means the humulone is decarboxylating nicely and imparting the chemistry you're looking for. If your hop is dried when you got it, it's already mostly decarbed so burn it very gently from far away! Toast it, with a light golden brown on top, don't burn it black.
Because the effects are so subtle and it doesn't burn that well, I would either A) If in a joint mix the hops with other herbs like chamomile, damiana, rose petal, and/or cannabis to get a more even burn and a fuller psychedelic effect or B) Smoke it in a glass cannabis style pipe holding the flame 2 inches or so above the finely ground hop petals, as the edges burn easily and it won't work if it's burned. Just lightly toast it! It totally works though, it feels calming like hop tea if you've ever made that, or tried Celestial Seasoning's Tension Tamer - the effect is nearly identical.