Depending on the genetics of the cannabis you are smoking, the effect will be different. Even within one strain there is some genetic variation between plants which can produce different psychoactive effects. some cannabis will have a more heavy, medicinal stone to it that will relax you eventually make you very hungry and tired. very useful for people with pain. other cannabis will be a rushing cerebral high, that blasts you into space. this cannabis gives you a racing energetic high. it is the most useful cannabis to most people and is found in the sativa dominant strains. I have hallucinated on several occasions from cannabis. if you hit it hard enough you will be taken on a freight train ride; smoking a potent golden cannabis oil through a heated attachment on a bong lead to the white walls fading to red lol...