Are there people who can't get high on marijuana?

Question

I smoked my head off and can't feel anything. And my friends can get high just by breathing all the smoke in the room :)

Someone told me that I need to try more and get used to it, and it will happen at some point. On Yahoo Answers I read that there's a small percentage of people who are immune to THC.

So which one is it? Will I ever be able to get high?

Edited to show notability: Here are some of the places the question is being asked (and often answered without the rigour we expect here): A B C D

Answer 1

There is evidence that cannabis sensitivity varies considerably:

CONCLUSIONS: Genetic variation in AKT1 may mediate both short-term as well as longer-term effects on psychosis expression associated with use of cannabis, possibly through a mechanism of cannabinoid-regulated AKT1/GSK-3 signaling downstream of the dopamine D(2) receptor.

Whether one can sensitize oneself has not, as far as I can tell, been studied, but generally repeated exposure to a substance will desensitizes you.

Incidentally, cannabis is thought to be correlated with psychosis risk and other mild but measurable cognitive deficits (even when not high):

Compared to controls, cannabis users showed significant impairments on quality of decision-making (Cambridge Gamble task), and executive planning (One Touch Stockings of Cambridge task).

In the absence of evidence that all negative side-effects depend on the ability to get high (psychosis: yes; executive planning: I don't know), and in the absence of evidence that one could gain sensitivity, it might be prudent to avoid taking large doses for long periods of time in an attempt to achieve an enjoyable psychoactive effect.

Answer 2

Cannabis plants contain 2 main psychoactive substances: THC and CBD. Each has it's own dose response curve which varies between different people. Though you can't be immune to any of them, you can still be less perceptive than most people to one of it or even both. There are many sorts of cannabis, which are divided into 2 large groups by THC:CBD amounts ratio - sativa and indica. Sativa is generally refered to have "High" effect while Indica seems to cause "Stoned" feeling. If you tried just one of them - try another :) I personally recommend you having a sip of "Haze" weed. If this one won't work, just forget about getting high ever.

As a cannabis user with a long length of service I can tell you - everyone can get high of cannabis, provided he smokes enough quantity of right stuff, but most likely it will result in overdose, which has a lot of physiological disadvantages, so I wouldn't recommend trying higher doses.

Also I suggest you'd use a vaporizer to smoke instead of direct flaming methods such as joint or bong. It will exclude a chance of you being intoxicated by products of burning reaction and mistaking it for being high :)