Wrong.
Meet the Cannabinoids -
http://www.sclabs.com/education/the-cannabinoids.html
Tetrahydrocannabinol (THC)
The most abundant and widely known cannabinoid in marijuana, THC is the cannabinoid responsible for the main psychoactive effects patients are familiar with. The compound is a mild analgesic and cellular research has shown the compound has antioxidant activity. THC is believed to interact with parts of the brain normally controlled by the endogenous cannabinoid neurotransmitter anandamide.
Cannabidiol (CBD)
With respect to the medical potential of the cannabis, CBD may hold the most promise for many serious conditions. CBD is a non-psychoactive cannabinoid that is believed to reduce the psychoactive effects of THC. Smokers of cannabis with a higher CBD/THC ratio are less likely to experience anxiety. CBD may also inhibit cancer cell growth 
Cannabinol (CBN)
A psychoactive cannabinoid that comes about from the degradation of THC, there is usually very little CBN in a fresh plant. CBN potentiates the effects of THC. The degradation of THC, into CBN, is often described as creating a "couch lock" effect.
Cannabigerol (CBG)
A nonpsychoactive cannabinoid, CBG has antibacterial effects and can alter the overall effects of Cannabis.
Tetrahydrocannabivarin (THCV)
THCV is found in largest quantities in Cannabis sativa strains. It is currently being developed as a treatment for metabollic disorders including diabetes. THCV has been shown to block the psychoactive effects of THC.
Cannabichromene (CBC)
More common in tropical cannabis varieties. Effects include anti-inflamatory and analgesic.
Tetrahydrocannabinolic Acid (THCA)
THCA is the main constituent in raw cannabis. THCA converts to D9-THC when burned, vaporized, or heated for a period of time at a certain temperature. THCA holds much of the anti-inflammatory properties, as well as anti-proliferative (inhibiting the cell-growth in tumors/ cancer cells,) as well as anti-spasmodic (suppresses muscle-spasms.)
Cannabidiolic Acid (CBDA)
CBDA, similar to THCA, is the main constituent in cannabis that has elevated CBD levels. THCA and CBDA hold most of the anti-inflammatory properties that cannabis has to offer.